| \¢62- Be ON | Ti 668447 ¢ ‘ Y Pie ~% » \ pone ees \k 5 CARRE oes a ot, \¥ A mS i A ay NY | ~ eee Nd i} ; i gS /i ce tates / f ; oe a jg N 2 {6 / ate P /, Le bd SY DEVELOPMENT AND TEST OF A CABLE -TOWED OCEANOGRAPHIC INSTRUMENTATION SYSTEM Prepared under Contract Nonr 3201(00) Sponsored by the Office of Naval Research ere a Cora Aeon eal Kee perl biG 4 SYSTEMS ENGINEERING DIVISION PNEUMODYNAMICS CORPORATION BETHESDA, MARYLAND WAAL OHM, o ThSthOU toeo O AINA /1alN I Technical Report 6634-4 PRELIMINARY DEVELOPMENT AND TEST OF A CABLE-TOWED OCEANOGRAPHIC INSTRUMENTATION SYSTEM Prepared under Contract Nonr 3201 (00) Sponsored by the Office of Nava] Research December 1962 Reproduction in whole or in part is permitted for any purpose of the United States Government Prepared by: A. P. Clark, Project Manager if NIN cal = Approved by: YAN Cua DN ete , Division Manager a af aye 5) L ¥ Y tat sail 2 a4 TABLE OF CONTENTS Page ACKHOWMEDGMEN LG cveve) aleaislevelisteleieis ielansteteralctal tener iaienete moomoo 2 FOREWORD Give siecleloielel sieiae telels te #el.e)'6) aile\iile) ©)\@) 0) [e/lelelleie el olieleleloveyeielcral eames SUMMARY 2 etateleWatclial alata laine fe FO OOSMO CONGO. oOo coonoUOdDodG ac 3 ENTRODUC TE ON so a's) wel sia'isvaneitehe (eiis/eve elle shevel ce ole ever enenen te eer ae eee GENERA) SYS TEMG DES CREP TLON sic oisreiniclaielete cio erie eens SYNOPSES, OF THE AUNVES TIGA TION: acre cieiciae eile ane eee eS DES EGNEDES CUSSION cr. areteieene erate eiete elie) clellckellellajelielslolelelsisleleloloreysmn lO, GENERAL oie sneha) sieves eels ei5 aie ai sy's, 3 1s) cyorata chenene etcrel ane ees ene emETIO) DREIRISS SS Olyeeatel chanel oiotenel eeveperere ee enor chelalelisieleVelelole)cliciiolels evelenir lO CABLE ciere wie) es © (s)(01(/ ©\(e) oln\ie)ho ve) (01(6)\«)\o\\e) siio)le\ ~) ollsicelie) otaliolel clei el obeisnercrerene lS CABLEGEATRING AND ATTACHMENTS os alee oe) ole eee eee CURED 'S epepeteliat ofe\ si vile lej'e' c's; 26 ere feve!o a moi) ol evenateie cheers ey ERR eT! BAN GCE RGAN DU STOP) nisl sys svevens: olove-wreiter lelete as oe eee ne LG ENS ERUMENT MODULE cts ovess «sie cies a cieveloivicie See ae ee aL eS RESULTS OF HANDLING-SYSTEM INVESTIGATION. .....-ccccccee 20 CENERZaeiersveloretorers oreneneiete rere sjeKetoholalelotelalel sifolelcls/(ototelslcotetotoieiee ZO) ENDLESS =TRACK: WINCH. ccc cvelc-e.0 sieve cieversie el areien le stein EO SHE RING OL LAW Diereparereperaer sper @hs lolol elexeKelleielolel olleliellsjlstelel-ianensienomer) SIPORA GE einlolciele) foneteietonaierereieree Sd00d0CODoGKOOObG5 Sd0 00 t DISCUSSION OF RESULTS vetoterceete oie sie otedeenl ore ehetotece eecse3#ese esoeeee¢se 29 PERE ORMANCE@ cjeteveva sfeloiets che ol vereiohara. oe ee ee 29 COMPONENT PERFORMANCES cre 5 elcverel fatale /e eee iinet oe ee 32 LOWeaSEVemMentSianereve cue ake Sis stores eee ee GENE x Ado iy aye ccc) or erel ss crchegs (sade te ie ee 3B DEDE CS SOM eis sicvele ors aisin s Lie ast o Gun OL om i-i * v TABLE OF CONTENTS (continued) Cablec cic. TOOL OIC IOTRO DO OOO GOO Gomme CICS SEY hoe Ws fey Sie Oucacrc pho ears Soc Se! evptokeyeusiesa ta euaere Fairing Attachments.) csictiews saree DouOmCC MOGUL eS. ccc wie-uo.c)e @ = oie (amsiate) aie eionen steno aicreeme Handling and Storage Bllementsis.\. ee g Le ae CAFO IP ) Ohl As \ ar , “ : i 7 An el 4 i . é Vu ; i i ek nf i ee ere i. f 4 Ae) eae Tc RANG GMa a ihe ] ’ y } SACRE Y tae An 4 a) AALS a a aye rytie Ae “4h . ee: ye oft 8 an : cba na he ae be tie Phe ae : oh Au eal RY ee: in Lam dy pate at na? Ae 113 “ih $ eh ‘sat ee ea pee Dery iol iil ha 1 f ie 4 3 ; wes | i ee , f rie b Ne he: ee Atte la oma Hen Re ’ seach Ge: eolae wiysth to in 13 aie Mh Ags Pb ahiod ves ie Pena % Rie 8 Ry . Bir, lehrm eta, P ay seh LAR seein Radtais a cube ek ae ‘aie | way, Ge pe 1a bia! RMS ESS 3 At oi tet ing Poa ety *) vit fms iar bre a ac shah relay tine ee ) ek p’ n> oh y Pe F Sieh ue ih oo 7 ish | 4a ss tyes ae r | Ne 7: . ' i ieee reba each ig Bi OR ) 1 ailnlene : ; Je ' Wi vibe Lee tae Pere ed sia we wai ot aiden ath dO avin debe fir. f wie “Ws ted win ‘yd Mima a pk) em 9 pee GAS Re Seed OR a a ripe! Li he wy et ‘ 45, wi gu: wile i ey Overt a ne | ta ace fb 4. sehen) . be Lat NPs aes ee RADA wing a barat} each tah o aid! oe fiesuban’ ys bet 1 ‘WD e aay wreedial y Bh deat ane oh: ti Monet, 1, i‘ is? ae Mas! & pint sta ca IEW eR ER! om eres rae a iit | satel fon : se jl i et : ae Rely hf ; : ' vedas : sy. ny , ae ii 4° we dat lt ey f r me seen 'y. ig } Py ah an ay Vi eee Pay ta \) Sar. nm) an o ee Ole, ot i-¥5 FOREWORD This report is the fourth in a series concerned with the development of a ship-towed instrument system capable of measuring selected oceanographic parameters in the vert- ical profile. This system differs from most other "profile" type developments in that measurements may be taken while underway, permitting determination of the "space-wise" variation of oceanic characteristics. Reports previously issued under this contract are: Wm. M. Ellsworth: "General Design Criteria for Cable- Towed Body Systems Using Faired and Unfaired Cable; Systems Eaginees ae Division, Pneumo- Dynamics Corporation, Technical Report 6634-1, October 1960. Wm. M. Ellsworth and S. M. Gay, Jr.: Preliminar Design of a Cable-Towed oe Instru- mentation System; Systems Engineering Division, PneumoDynamics Corporation, Technical Report 6634-2, February 1961. L. W. Bonde: Investigation of a Tractor-Type Winching Machine for Handling Faired Cables and In-Line Instrument Modules; Systems Engineering Division, PneumoDynamics Corporation, Technical Report 6634-3, July 1962. In this report, the development of the submerged towed elements of the system is discussed. A preliminary investigation of a winching device is described. en ji ni ; “ue pe onan vidal ae pied: es aa i nh # Me Bier ws) ‘ ital are. io 0) AF RPO: se W) od ac ap? Tages aS ate deh Willie cer dean my Parl ' : eet said Pay vey : Pt Sue Bey asi be = pd one at. ay dit ah ok ni ay Sibel gt ad SUMMARY The components of a cable-towed oceanographic instru- mentation system have been developed and tested to demon- strate hydromechanical feasibility. As part of the project, a depressor, instrument module, and devices for attaching trailing-type fairing to the tow cable were developed and tested. Designs for these elements are presented. The investigations also included a basic study of specialized winching equipment capable of handling rigid "lumps" spaced intermittently along the cable. Representative elements of the system, including the winching equipment, were tested at sea. The results of the developmental and sea tests verify the hydromechanic feasibility of towing the system to a depth of 5,000 feet at speeds of seven or eight knots. ‘The capability of the winch in handling and storing cabled fa intermittent, rigid "lumps" was also proven. With feasibility established, development should be continued to finalize the design of the winching and handling equipment. Design studies on the data-—transmission system should be initiated. INTRODUCTION In May 1960, under Contract Nonr-3201(00), the Systems Engineering Division initiated a study of the requirements for a cable-towed oceanographic measurement system which would permit simultaneous measurements of selected oceanic characteristics at a number of depths to 5000 feet. The results of this study were presented in two technical reports (ive and (2), the latter of which was concerned with the re- quirements for the towed elements and shipboard handling and storage of such systems. Preliminary requirements for the instrumentation, including a method for sequential interroga- tion of as many as 128 sensors using only a limited number of electrical conductors, were also presented to illustrate the feasibility of transmitting such an amount of data through a cable small enough to permit the use of acceptably sized handling and storage equipment. A recommendation was made that further developmental work be directed toward demonstra- tion of feasibility of hydromechanical specifications, with minor emphasis on instrumentation problems. Hydromechanical feasibility depends on the satisfaction of certain conditions: iho The submerged elements of the system must be towable at the design speed range; *& Numbers in parentheses refer to references given in Appendix V. a. When towed with design values of cable scope and speed, the in situ value of the depth must not be substantially less than 5,000 feet and the in situ value of the cable tension must not be substantially greater than 15,000 pounds. Die The components must be structurally adequate; and lo The tow must be stable. Die Winching equipment must demonstrate satisfactory: a. Inhaul and payout of the faired cable without damage to the fairing or cable; and 19) Englutment and passage of the instrument modules without slippage or damage. It was considered that hydromechanical feasibility could be most effectively demonstrated with an engineering model constructed of full-scale elements of the prototype system. Development and test of representative quantities of each major element of the system was accordingly undertaken. Arrangements were made to test the resulting model at sea with representative winching equipment. The results of this program constitute the subject matter of this report. Since this document is essentially an extension of (2), liberal reference has been made to that report for explanation of the underlying philosophy and design approach. This report presents only component design con- siderations in those few areas where significant changes have been made in philosophy or approach. apie ctnyie 7° oe Ye : @ > a hs o', Belin UN how , ia + Jnite-t.9 vy! i 7 ieee me.” 1% zs . i 1 f “ay Py i Bax 74 j \ ta & i) soe e f es 4 bd % ( ~ ’ \ pad Re ) r t i ti : sé Me hina ares My % hin am) ” WT By Rey r § “et aah ey “ih OT upie Ce GENERAL SYSTEM DESCRIPTION The system, shown diagrammatically in Figure 1, consists of a number of lengths of three-quarter-inch-diameter cable coupled by pipe-like housings. Provision is made for instru- mentation in the central sections of the housings, with cable terminals and appropriate electrical fittings in the end pieces. The cable is covered with a free-swiveling, hydrodynamic fairing to reduce drag and vibration; the instrument modules are also faired. A core-space, to accommodate any suitable electrical cable, is available within the load-carrying cable armor. The cable-fairing-module assembly is retained at proper depth by a depressor, which develops the requisite depressing force by a combination of weight and hydrodynamic reaction. Shipboard handling is accomplished by an endless-track- type winch for systems with rigid instrument modules distri- buted along thefaired cable, or by a twin-load-drum winch for systems lacking modules. The faired cable is delivered to the stowage area under a low tension, permitting storage in multiple layers on a drum or in a well. For convenience, the elements of the system have been grouped as follows: eG : ' Mei b pres jie yieaiy' mie ‘ =” s Briss: a es es ye - [ ae: meer St0— 40. pee apoa sar? 36ers : i = 5 a3 G hl be hb worl! Q@tisay ue ate oe ee @ 7 DO ie Me Se ee iat, So) ASS) ; ‘) ee J ett § Die "ee? aw) “ 7 ’ >| » ott 4 ae | ‘A - - Wwe" 7 —* ee Th) eid ia we » he tei“ : j é 4), , , é a uy 0 foo: as, bgt te st) eS00 heey | OS ee a ey ee ee ae oe pow ie ; te 7 zs 7 aT Sipe y J) oS. % a Bry ft A C a HY oes Seg hs a , is Pipes) hed: 4 ? arpie ari! ho-vis ph J “ ae a 5 ’ » « a B4e U va ~ Pape 4 5 he Be BEE SOL ns Me CA © Kh 9 a OS ae a ae ee eX Omer ee ‘ : } fee Rah Se ay ya ite} ane By a Thal i 4 ey) wine, gn : iy Se Tide S yA mn | 4; ii ! é : ; + ! fae | A & { he ee , 1 =b, GBLane ad = ‘ . e @n%. Fi eg iwRD. . a wile rhs 299 ; 7 a. : =a y. : Re | gd y — Storage Drum Traction Unit Stern Sheave Fairing Terminal Clip and Support — Cable and Fairing _ Instrument Module Depressor Figure 1 - Generalized Arrangement for a Cable-Towed Oceanographic Instrumentation System ~ Towed system: all mechanical elements that are placed overboard; Shipboard-handling equipment: all items necessary for launching, retrieval, and storage of the towed elements; and Instrumentation system: all equipment relevant to the sensing, transmission, storage, and dis- Play of oceanic data. a ne } y uF ; OT. GO 4 i nee, 14 J } ty Meek ati 4 wee bis ne’ Sree See! Levi gy: neat ae ? | ee " Salas ee Sat Die wid hare 5 » 7 ic ee a te yy PORE NOAE. OTe) RY Fae er) Wag aos db SYNOPSIS OF THE INVESTIGATION The elements of the towed system were developed along the lines indicated in (2), and subjected to tests at sea. On the basis of the tests, minor modifications and improve- ments were effected, and the design of the towed elements finalized to the extent possible at this time; the resulting design is presented in the following section. The details of component development are discussed in Appendix I, and the description of the sea trial is given in Appendix II. During the development, a major change in the length of faired cable was found necessary to attain the desired performance; this is discussed in Appendix III. The feasibility of using an endless-track-type winching machine for handling the faired cable and instrument modules was investigated. Comprehensive tests, to determine the effect of cable fairing on the machine's tractive effort, were conducted with a commercially available unit? a sea test was carried cut with a similar, but larger unit. The results of the first tests are reported in (3); the sea test is described in Appendix II of this report. A very limited investigation was made of the problems of passing the towed system over the stern of a vessel and the final storage of the system aboard ship. The results of this investigation and a discussion of the winching problem are given in the section headed “Results of Handling System Investigation." Oe Sub syd a. +; hi. iu. heal 9) 7 7 }! \ rer i' . 5 a iy Jina J s #4 4 i (ioe > ‘ — as 4 é ° ‘ é ‘yar DESIGN DISCUSSION GENERAL As illustrated on Figure 2, the towed-system design resulting from the development and tests to date consists of 8,000 feet of cable covered with a freely-swiveling rubber fairing and additional unfaired cable to permit rigging. The instrument modules are placed "in-line" and serve as electrical and structural links between the seg- ments of cable. The depressor is attached to the botton- most module. In the discussion of the components that follows, the relevant SED Assembly Drawing number for each component is listed to the right of each heading. m DEPRESSOR SED Drawing No. 50068 The depressor, shown on Figure 3, has circular-arc- airfoil wing sections and flat-plate stabilizers. The structural members are fabricated of plate and bar stock, the edges of which are simply rounded where streamlining is required. The structure consists of welded subassemblies bolted together to facilitate proper alignment. The two ballasting weights are cast in halves which are bolted together; each weight is then bolted to the forepart of the structure. If desired, the unit can be disassembled to facilitate shipping and storage. All nuts, bolts, and movable hardware are made of stainless steel. 10 7 Ma ee * y 7) om Yo Lh is af Fi J ‘ oe! ‘ 4 ‘ aa Ss ; ? e Xs an 9 1)') Pind ; . on 4 2 a i] <3) 4 read 4 4 ; ‘s @A yRiei ieee a ae ad ae A) aye Fe ‘eh 2 ij "7 A. nwwes ‘a 7 <3 ’ y ti j " ss Fi ‘ vba i a $ vt 5 we n- Fy » —— sO000 FF 20004T — 200g er. ee, ARE roe. 200 FT- 200 FF- 2ooer Tre 13 A> =m 10 1142-1 i oy C@— oo—/ -/ CABLE ARRANGEIIENT 0,0) Parana Rec (\4) TACT2-sex 12 De C AHOES O12 35-1 ONE APPROX AS SHOWN \ 20006r —S \ —— \ON\Ae=1 +— J \O1 (39-1 CUT FAIRING TO INSIDE \\or came tre \ af t Ege es Oe vera SCALE ~ QUARTER — (01\36-1 262 Lian) DETAIL B SCALE ~ QUARTER NOTES (with CABLE Loaves BeTWeEL 200 -s00Lgs TENSION STRETCH FAIRING To so” Tension 2 PULL TEST CABLE ¢ MODULE To \5,000%, TesT CABLE STOPS TO 300° USING FIXTURE SK 1250 @ ABLE LENGTH TOSUIT FAIRING IN ACCORDANCE WITH NOTE! ane oe ar “ae wry) Depressor Developed for the Cable-Towed Underwater Instrumentation System Figure 3 12 Hei aa «le i an ey Pa 7 a ey * NA r tC) i hag ty oe i) , Bre i f Aw at) " ly ! f ‘ yl i's t i ‘ f ee yy ee 5) ae =a"), : hi i , J imal Ob in Sy ga’ fie ¥ ie > Md tT r j f LP } fhe Ow ry i) ‘ r ; : i if fh, eS ; i *v t f Ay i Sf a ate a ON rll ne )Aefierd es ee High-drag areas, such as occur at the junction of lift- producing surfaces and other structural members, are enclosed in Fiberglas-reinforced plastic fairings. The horizontal and vertical stabilizers incorporate adjustable trim tabs so that the depressor's trim can be maintained or changed. The assembly is finished with International Orange enamel. CABLE The cable is of double-armoured construction with the electrical leads contained in an insulated core. Approxi- mately one-half inch of the overall 3/4-inch-(nominal) - diameter is reserved for the electrical core. The overall breaking strength is approximately 45,000 pounds. These cables were originally developed for the petroleum industry for use in logging deep wells; they may be obtained from several major American cable manufacturers. Details of the core construction have not yet been specified, pending final selection of the data-transmission scheme. CABLE FAIRING AND ATTACHMENTS SED Purchase Specification M.S. = The fairing is David Taylor Model Basin type TF-84. The letters "TF" stand for "trailing fairing," the first numeral designates the ratio of the maximum thickness of the fairing to the diameter of the cable, in tenths, and 13 ee ¥ i , ROLY rue Pc Se" ( p : x ale es 7 @ } Pe tet ey yrdedi Na , ; . i eiehietss wl Sadipche « hires Oy Cede a ck) woe ; ' uN Fe SAAT eyeing Vy Oe Poe | lay | < i fy 4 ; * Si, v ' & } ) A a ee a AOD ee) ro ioe? pe Aes ey Pe ea ee the last digit gives the overall fineness ratio, i.e., the ratio of the overall length of a right-section of the fair- ing plus cable, to the diameter of the cable. A trailing- type fairing with a thickness ratio of 8/10 and a fineness ratio of 4 was selected. The fairing is constructed of a single-durometer rubber; the leading edge is reinforced with a five- or six-ply Dacron tire-cording to provide the necessary structural strength. The ends of the Dacron cording are turned back to form a loop, as shown in Figure 4. The fairing is to be procured in maximum lengths of 200 feet; shorter lengths may be specified, as required, for lesser module spacings. It may be produced from Bureau of Ships Mold G60818. CLIPS SED Drawing No. 101137 The fairing is secured to the cable, at intervals of four inches, by clips which encompass the cable and are free to swivel thereon. It is attached to the ears of the clips by rivets passed through the rubber body aft of the Dacron-cord reinforcement. 14 ha NA) vy i iv WW ; Ai) Loma) lak Mania ah Ria) ; ¥, | ! i | i et Saks f y ‘ ie i ‘ “bad. Ge rs hie Meer ee a ee Ano e Rie is 4) ae b vive ae Oe ln Ree! ORR, Tae ot Bia ies 1 H y yee \ ete Me ee: amelie sath! Oba ARATE eRe ama Fabs ae sh ie a eee Fe kes . : uke fri ree DAs yy pte = | we hia y j <4 we vant yooh aan: fh tht.) Ae ' 1 Mi rhe J aoe na ty ps # Y ee i bien te NCL al rae Vitae Bao AiO nie Ma et » H itis Pa) \ j x f La’ by =~ A ce ne i ¢ f io j uPA y A is a y. y 1 j ¢ ‘ 4 i % ‘ aetehs Mey) pip oy k; ; DVR Lae % ‘ . i PY pgs Lae Apel t GOON hie ue ak . wae see ey eee = adi 8 a de eras LOY aap A ee = oh ee oS an ih Sot bathe int Dacron Cording 200 ft. Figure 4 — Cable-Fairing, Trailing Type, iS ' General Arrangement y PoP hhc ee CC eS RR "ele MGS S7A4h re Bi dg! pur PY ay a or, a ik be a ee) (#2 pie Vey Oe a 7 oa HANGER AND STOP SED Drawing No. 101136 Each section of fairing is terminated at a hanger, to which it is secured by means of a rivet passed through the eye of the loop described above. An alternate hanger, used during sea trials, permits the Dacron cording to be termi- nated without the loop, thus affording a technique for effecting repairs in the event the fairing is ruptured or an eye pulled out. The general arrangement of the developed hanger is shown in Figure 2. The principle of operation is similar to that of the alternate hanger shown on Figure 5. The hanger spans a stop which serves to transmit the hydrodynamic load of the fairing into the cable for those lengths of cable fitted with modules spaced more than 200 feet apart, For module spacings of 200 feet or less, the hanger is attached to the module and is free to swivel with respect thereto. As may be seen on Figure 5, the stop is simply a split, friction-type clamp with sufficient clearance between the halves to permit them to bear on the cable when bolted together. A resilient elastomer pad is placed between the stop and cable to aid in maintaining the clamping pressure when the cable diameter decreases under load. A sand- impregnated polyurethane liner, developed by the David Taylor Model Basin, is used for this purpose. Self-locking bolts are used to secure the two halves. 16 GW hh att LA NA Se TTS TE HR iy w m oe Seer ne yy Re, ee 2 Me ‘ ee i : ~ ps ‘ a fe inyly b Ain vy agi ‘ i fiat prog “ ‘ aves Ms ome fin ‘ie ae | wth Kip Ha My: % ' ’ ar jas AAO O BAKE) , pine be ¢ je 1 1 - v7 j a rer 1, v ha y oe i \ as ‘ st Pe hs wri [ + 4 FP eet | i at $e Te ” * el 4} Ee Af ia “ a 4 7 nl I i : : ae uit é t i ize ‘y Ki ae aw) Fotis) ey) et tS ee - % H GbR ae ‘ het ois A. . : | t i EPs } f Peioy. ta Wise iy ah sg 4 “a Br * ‘ s} - i" 3) — wey ayatad woes woth 8 154 Bi Cea E ; ‘i i : : . Site Mres se hyray ’ v a Hl A i One ee Bent Red iy ’ SA > Pol ph ‘ } i erp f an , i ‘ i i ; 4 ; a f ‘ Ps Al nt : ‘A Wt AS eae %5 — Dacron Cording Section A-A Sand Impregnated — Polyurethane Cable j Liner Fairing —, | Ye Terminal Hanger Double Armor Cable Teflon Washers Section B-B Figure 5 - Stop and Fairing Hanger 17 INSTRUMENT MODULE SED Drawing No. 101139 As previously stated, the instrument module is a pipe- like housing coupling the various lengths of 3/4-inch- diameter cable. In the present design, shown on Figure 6, the body is closed at each end by plug-type bulkheads with O-ring seals. The module shown has an end plug suitable for mounting a pressure sensor. Commercially available, bulk-head-type, single-pin electrical connectors provide the means for transmitting electrical signals. A commercially marketed cable fitting is used to terminate the individual load-carrying wires and transfer the loads to the cable- fitting housing, which may be rotated relative to the cable fitting, permitting attachment to the instrument case without rotation of the case relative to the cable. The cable fairing terminates at each module, which is, itself, faired to reduce drag and vibration. The module at the bottom of the line also serves as the depressor towstaff (Figure 2). 18 ome shh Wwe, Lourlh GEE, fi ety! rer ne teak) “¢ acdgin! evGinie, a yi iseiood wt mwand oie ve © a ‘pduties tweet a i Maju ctnbawtes hipelnquan oot hie coy Oe Bape ed eon a, ee aidan weld bre fake’ mode. aloe net (ae kood werhlin B ; . wy ee a Pe eee Peery a a & Pld Porore seat : of ae pred viien Siesteomee Lane Oem haem NB wise iki nN Uitebeiiteny * BA 098) (224375: it ‘gna nkinens wee hiieanel ay Ath i UiGal ocr ead >snatadr es’ Lome 4) ie hla mays bo idchingd, See Se Edam, wie) od Mbytt gee agi yt iam Ee Imby rgtcctiinl he "iptecos eA ons ut retex boi ee . re twee aaron Se ; Svlivi- Bia Atsrcoy ANA) wiih nent ed ls ghd aati jpn agie eitio ad! 7 wee 7 ws ae tid ie ihe ‘7 eT ey: ee ee, Mee a aaa wiitae vest a0 ) PPTL <4 MD enema pa, ‘Aa ‘4 tins Raee-hy eerie Othe fist of) tk ‘deh id eae aR. oS vente inset ik OD) hi ote ait, : a> Ci DRILL ® *.1e0P Ww=i4 | / 1O\146-10 (i Y, ker / (45) NOTES (713.14, 415 PURGIASE FROM Mecca CABLES SERVICE INC FoR CABLE .755 0.0. , 24wiRES INNGR .cc2 DIA ZawWiIRES COTER C72 DA. OD, \.ces J sovei- 5) ton47-1 Le = Fit CAVITY Goth eNOS LCoAT THOS WITH -1C [-] tonae-\oT TCASLE REF, = SPRING AN, |*S20i4« MLC, CRI WASHER Ton3a9 || -14| Loce NUT Ss pe = “13, THIMBLE : sass = “Tir Ser sceEw se Loc! BALE ROG Pe CERT YARIS 8 a -20 OF Tz & [7] js2) HO|FEMALe soy M-25-Fe ea7 I {2 | |-9 — } —— —+ 2) COM'L “8 ret | | li] torre _ 2/potiai 1 | 1] teso- Fave lens = BACK UP RING | PARKER SEAL CO. 8-233-™ ef: RING [47-747 BUNA H 2H 1O43 PLUG ASSy | ioe FITTING | UG ASSN. Boox UST OF MATERIAL INSTRUMENT MODULE ASS INTERNE DIATE Figure 6 San ae 19 ak v7) re . sly pe ‘ee ee JT)! SAT pan tA a oes ae a5, ti Pde Wa ean rm Haag ne :. aeteh wh ali tn oe ae PS ed ee I ae Ee a al ae ay loading cylinders and the geometry of the linkages connect- ing the pistons and track. This machine did not satisfactorily englut the modules tested although the faired wire rope assemblies did track through the machine without damage to the rope or fairing. Some deformation of the fairing clips was observed, and it was noted that the rope tended toward the edges of the treads when slack was allowed to accumulate at the point of discharge and when proper alignment of the rope was not maintained at the point of entry. The second winch, manufactured by the Western Gear Corporation and marketed under the trade name "Cable Hauler," was tested at sea with full-scale faired cable and a dummy instrument module. This winch, shown on Figure 8, and its installation for test are described in Appendix II. The purpose of the test was to evaluate the proficiency of the machine in handling the faired cable and module, to evaluate a roller-and-guide technique for orientation and direction of the fairing, and to determine the tractive effort attain- able with faired cable. The details of the tests are given in Appendix II. The winch satisfactorily handled the faired cable assembly, and englutted and passedthemodule, as shown on Figure II-2. The roller and guide assembly satisfactorily performed its intended function. The maximum measured line pull was just over 10,000 pounds, with pressure of 110 psig 23 ‘a Pamir wally f 4 f jig » are. ‘ , 4 a, iki mo 7 tw, fal : i 1 Big PERT AAR Ty nv Hers aa a a) er Bub. 2 f° 8 ay Zi Oye ate iy Rt » Trak %y ; ey © Ay i] ’ pint Ow we ‘3 Tah an Mae kes hh eS Beer am. y Yeu rte real a } 4 > at vo ws ee Wee Ng *y 8 ne gy? © i» : Osea O24). Bo eet are te nie le . ht DE AVR AMay rai ore 0, 2 us ge all a : : “e. p ak AA ee g eanbta »JeTNeH eTqed, uotT,ZeATOdi0D zeeH urs Asam hen a 7 ae re applied to the track-loading air cylinders. Slippage at this load occurred when the air pressure was reduced to 90 psig. From these data, and the geometry of the machine, * a value for wp of 0.29 was computed. STERN SHEAVE Three methods of passing the cable, with in-line modules, over the stern have been considered: de Single, large-diameter sheave Use of a single, conventional sheave would necessi- tate a sheave about twenty feet in diameter to pre- clude excessive local stress in the individual cable-armour wires near the fitting which secures the cable to the module. Ds Tandem-sheave arrangement Excessive sheave diameter could be avoided by trans- ferring the cable between two tandem-mounted sheaves, avoiding contact between modules and sheaves as shown in Figure 9a. The diameters of such sheaves need not exceed the minimum requirement for rea- sonable cable life (3 feet for #-inch-diameter cable). — The lack of agreement with the value of / given in Table l for equivalent conditions may be attributed to inexactitude in the pressure measurement, the use of double armoured cable rather than wire rope, and friction in the mechanical elements of the track loading system. The use of double . armoured cable should yield a real increase in the value of 4», due to the lay of the outer wires; whereas the in- crease due to friction in the mechanical linkages is present only because the measurement was taken with de- creasing pressures. 25 . » i, ; ; . ; ig ia ee 7 n wat i, } a ; ae any, i y Us i) Ay v7 ‘va, ~ P wai} ie Pe Oe ae ; a ; wii XY , } | ; j dj ey , Mpg Pn oa Mi Tw coh <3 ’ ie iy 2 ee ‘ i a 4 7 ” Pot ays - ‘ i ae ‘ if u. ne \ a - -@ a v j — ~~ mH ; ’ N f ne Fives WAOUddY @) RESIS BsIAO sAGOW SNISSva doa INSWS9NVERV SDINVNA(JONNSN |} NONSIAIG SNGSNIONS SWALSAS TwitaLww JO 1SI7 NO1id!1u3S30 SNOISIASY i ay. ) va ith : y a eo if We QALR 7, j ‘ 1 it ui 4 i encTOh ide hues Al inhi, = Pei _STORAGE As shown in Figure 9a, an actuation system would be required to transfer the load from one sheave to the other. Single sheave with lift-over device The cable could be passed by a single sheave, about seven feet in diameter, straddled by a segment of a larger sheave functioning as a cam (Figure 9b). On the periphery of the cam would be a receptacle for the module, at each end of which a groove would sup- port the cable in such a way that the axis of the cable near the module would coincide with the axis of the module itself. The cable would be led about a segment of decreasing radius so that it would exit from the cam on a line tangent to the periphery of the sheave. The sequence of action required to lift a module over the sheave is shown in Figure 9b. An actuator would be required to engage the cam. As discussed in (2), storage could be accomplished in several ways. Cable sections could be decoupled at each medule and the cable layed out in deck wells or reeled onto a multiplicity of small drums. Alternatively, it might be stored as a unit in a well or on a single drum where the problem of fleeting the module-encumbered cable onto the storage reel could be avoided by traversing the reel rela- tive to the winch. 2N7 ; I ¢ i, f : - i peivis alison ©, Tio e ot 29 Rae ids et oe toh see wept ? | | a Peei kao, ods oe) nae ‘tt ARE us nme ” pes ; OF Feta eeiy Renee Ao, ate newne . a ¢ ot. enoe iba Gwiatie gi \ vaseatel Mau a. ¥ aeeheat ne > HIF RE Rpia, ox? bagespnae os hetidiidmeonag oa Jef; “apie! vt ay aM nent ene ves F ; ‘ I fh a 64 ie i IC am Peary G's Tio diagbon weds oh eta tue wm ditt DAES ey! the aT ae +8 Biel i RD eae: itd ‘ea set ‘ veh ol ” te a A) ATPL AM Lea GRah i Yo y aid hah Fig Aa, Ae old Mk SS CBee ee, BO ta i Wt Me 7 ie 2 He” rad Oot hea pete SP acy or wading Poidectbs Bee a toni toler Lene eit: phdeaer dee vd), Gab fav) wt beige hoe OR ety se oth ‘ae i . se : fe Loney | Faas iy j a - ee ee ee 74, SUPPORT SHEAVE DRIVE UNIT FIG, Se SYSTEMS ENGINEERING DIVISION ARRANGEMENT FOR PNeumo Dynamics PASSING MODULE) uae OVER STERN BETHESDA 14, MARYLAND > Aah eee : = 5. 28 DISCUSSION OF RESULTS GENERAL The objectives of the present project could best be accomplished by investigation of only those factors repre- senting potential problem areas in the realization of the design goals. In each such instance, analysis or appro- priate testing of the specific elements was performed. These individual results must be appropriately weighted to determine overall system feasibility. PERFORMANCE During the course of these studies, it was determined that the resistance of the faired cable might be as much as fifty percent greater than that assumed for the preliminary design. The effects of such an increase in the resistance are discussed in Appendix III. It is pointed out therein that the depth objective can be attained, A spite of the higher resistance, by increasing the scope of faired cable. Effecting such an increase without exceeding the limi- tation of one-third the cable breaking strength depends on the validity of the assumed hydrodynamic-loading functions. Two sets of computation, one by Whicker (4) and the other by Eames (5), are available for estimation of the hydrodynamic forces acting on faired cable, and for prediction of result- ing geometries. Whicker's formulation is the more general; Eames’ results represent a special case. If the loading 29 we inhe BES Bor! tse ar Hg se Caines wan gee yhonS ht a W" i epbemayaeee + NP teh) Oe Yh agate hers S . eect (9 me we: jie a ated ol a ‘i - . r ence an geass yale prc te ne bt rita IT ee okt a ihe ae OI 7) | 1) ane ee eee al Ba Babs d eet ce eee » ba 2m Aug gna a Setamesae WAW | ae Hee mn avin grat hey OPE: gh eahh OP 8 my eve > ws apie 8 Robes mies baat Seer 5 | 2)! im 3 pe ltas yl Bert in eo PO gy oD had i He igtaisaple ME nate Oe OS OS > OF © O&O SS OF SO SS & & OS ww OO we ow Sw Page III-4, the significant curves are those which illus- trate variation of scope with towing speed. 31 iT . + | didn dethew? wiver Same wary ,aatsotn gee thy | 1 oa a Oe Le ee 6 ee ee ee eee is ¢ Mi Seay AV s 7 ree, Pr he i. al? alan, a A +e i1hGo2 © ame wey Ges iguiais snot" 12 eiuan st? AN Sie Wh) SAO cad FH Midian g. i.e + eee Ge aioe ees ny Ka oe 6 ee , 72: ele pei @ ERS BF eR aes fone ) Leeleusheay AW vibe rere G A BPE BHD VPRkS sewn wie 2eAlas FS i a? > 4 ae: ALLL wes eae Be [eth Wks ae anepemed Pa dracear 6. whole stetts ws fe ¥ ' @ i t x 4 ° @ - » Dhue ~~ ey ty > i rT? eM Lay fo be At 4 “ee ON jin ee AEROS & * af * ay} Ree wor + i ‘ A ie Wig ov Bia J at ‘he wit ‘ "i thy M ven 7 + oe, .'. yt ‘ Q P AP eat ou Plt. nes hie 8 ie Vie, Be 46 a“ ; web J POEs KE UF Behe r | t me cy ert hx ‘ ¢ ii le ANS ats 3 My o) care othe ne Me PG) by nay) A he : aN are. Wb aye UN Bieriiy er % Spud ng MACY Sh t yA AS td nrg Heyy) Tate " Say Lt Wise dat, ioe ult aks teak ety n pat 5 Fete aes i : pdand >) as eee we i ee ee tha eet eenee, 2 MOR Lay HIRES. di ge pet ae iM "he. + i Oa TORT? ‘ i ge eee yh ed aa 5 i eb hes } a * NG Fs id ey } yy Lin i arts List iy ge ye! wt: panel dane! “ «ea TY ew ¥, significant results. The high seas in which the tests were conducted caused the tensions to fluctuate continuously, so that only 5 range of tensions could be observed. Ideally, such a test should be conducted on a smooth sea, The rough seas did, however, remove any doubts concerning the dynamic stability of the system. COMPONENT PERFORMANCE Towed Elements General The sea trial served to demonstrate the structural and hydrodynamic adequacy of all elements of the system except for the instrument modules (which were not subjected to maximum hydrostatic or tensile loads), the stops and the cable. The adequacy of the first two components was demon- strated by other tests, reported in Appendix I, however. The cable is certainly adequate for the static loads if the limit placed on the maximum allowable static tension is not ex- ceeded; the overall adequacy depends on the maximum dynamic loads expected and will be discussed later. Some minor im- provements to various components were indicated as a result of the various developmental tests and the sea trial. Depressor Static instability in pitch was observed during tow tests with the original set of horizontal stabilizers. As is explained in Appendix I, this condition was corrected 32 | _ slaggelee 0 dugg 8 co chavs esi ad Bank = ‘an areeey 2 ee oe ah i Od Bilmee vita wos ah we! ee oer bestia? cad os Fay ia Sie he es a? Yee itt d ie <6 nm oo eo Sort ee | iN Wad ie se - } ers bits pura ert Magee mpoimeb £e¥ eohaaotans eyes ewKka sir BOG Sie" Tass vita a is eianaibe ag oF Pliny’ acey, schlaial wii) CTs mines pete & oy ee on “he sto "Se Capi Pree a ae SR hee aban rita ip ate a paces th syatel ica aed, eeu: ag St PL ae eet aa WARD .. %* wit, palewh) bev 29nd sb" e URE ACES AD cod toll OB Pak” el Pe Ser see Mae tee Dial pega | ay ] ae : cert ae ¢ by the addition of horizontal and vertical tip-plates, as shown in Figure II-l. This configuration towed satisfac- torily in basin tests and at sea. These extensions are vulnerable during handling, however; Figure II-l(b) shows how the starboard end plate was bent during a launching mishap. The extensions also interfere with storage on deck as they protrude below the rear supports. Observation of the towing characteristics, made during the basin towing tests, give indication that the deficiency can be remedied by effecting minor changes in the location of the stabilizing surfaces. Cable Surges in tension of approximately double steady state values were observed in the system during the sea trial due to high seas. Since the system was at short scope (700 feet), for which condition the cable angle at the towpoint was quite steep (61 degrees), any heaving motion of the towing vessel must result in a corresponding heave of nearly equal Magnitude at the depressor. The small margin of static stability in pitch of the depressor, and the location of _the towpoint well aft of the main-wing quarter chord line, | result in characteristics which tend to minimize response in pitch for disturbance frequencies of the order encountered during the trials. The depressor on short scope is thus literally pulled vertically through the water when the towing vessel heaves. Making allowance for human error in judging 33 eae tea wre, pret iiesa gen, Mest ao om Hiishs dma " ved a ee | an unwe PRA at xst’s a > ie ve wane inguin iy a ‘ns Lee na ee oe i Aa ayo hag Ci mv hs 1h ae MO. Maa yeh to wieder 9 oe ee bad aa aoa a : ie meer. waite =f e VN ied higigrett Nalree ates ert a) aA Re ARR: ; - oy ’ ; ; Lys Bhi ; eT *é Te ke ae : er ( ie si ON pea HESS. : ai SYED Ee dine ba A gi 14) i 4 PRBS Wels hae ‘hell a ~ : la aati ae 7 AL 7 is m GV) age 2 Sa st hak biol nes | Sigal co nhs ee OE wis ths OU ss tae 8 ly ch f a ‘ : I Ee ae Pe ee | ee | th Mane A DL APES ites Bee , eGR. Bwrses Maha kc pase) Al ik iah bas he Rt LY et it ie st ob ope ee) ; ¥ aise + cred RR! MRR hated Meena aaa » a rit aoa a a ha? SOM ee! at ta % " We epedy set “Wb tea adi pat yp vastly aD iy Te ig ¥ q: ohbepaa nt wy ‘Poi wldwae st) vote fi» Try ae CL ke atl NOS eat ah Caee * fe vtieh iavane ‘ome if a ie 8 1 laa hee, ae ae 1 ae oan ‘i the motion of the vessel, the maximum total vertical motion of the fantail of the test vessel was about six feet. Since the period of the vertical motion was about six seconds, the maximum vertical velocity of the depressor was, say, i x 3 feet, or about 3 feet per second. With a forward velocity, at 7 knots, of roughly 12 feet per second, the maximum increase inthe angle of attack at the depressor would be about 15 degrees. Since the effective angle of attack of the depressor is approximately 14.8 degrees, this would correspond to doubling the lift coefficient and hence the tension, which is about what was observed. Conversely, on the downstroke, the tension should have dropped and it did indeed fall to extremely low values following the appear- ance of a high surge load. The foregoing discussion is overly simplified, but does serve to illustrate the problem that attends large motions of the towing vessel. This situation might be alleviated by decreasing the impedance offered to the cable at the tow point. It is possible, of course, that pendulous motion of the system might thus be excited, with equally undesirable results, but the fact that the cable experienced no pronounced fore and aft motions during the periods of peak surging tends to discount this possibility. If the mechanism discussed above is responsible for the observed surges in tension, increased scope will undoubtedly 34 : we. mye P\ PL, FY. AWM Teta) ooenll o° sii ft uotee Oh? ko Pino mh : A i Bare JuGr May. See RR Scot Om! ae ae Cine ee ills 11) db : ; ' se einer? Shin Sirhan e) Hoy tad Oe ee A cae us 8) ona seiianet ats) ae a a a ios sie Piers) wri Ate Vy i 41 tt ea A) an ee eee Lely feet Yee A 0 ke Oe tay) ok ; Me ho Fas hes aa y ure i= aT xi : ve th " i Tile Pict y F , ‘ i Sib hambet Kah. 26R) Ty ( pv OF | 2h are Ce os i ak Geyese ein? ahh fy Bose, ek OR: mae ‘phekerbink leaeiion il ee ; te ieas = : , ’ eC 1. P DS , i) ; ly wy tt Pere eS ie ee ae We eR: a ale rae oe ee : a4 44 ntiesls Meili. PAR i ie) Oe ae B'S arian re * he . pubes / — H Le re i 7 ree ; gi * went rs ¥ f a en wil) Fete, iy TEER 5 shot 4, eet ean 9 Reset oy ay i i \ , « ewe Sere Vai a) ee + at eR fe a. Pipe ‘Pps oe, yet LARS ager iy Pee & uh Bike WA AN AR WE hs Led Ds Baek Sy Bisdeet beet WF oy Weed / Eh ik. CAP OAT eR MN et og ae On ee =e sien “aces ret el Sr Lael, Nap ee ad Oh ve neers sdn Ae ah? SP lt 2B Pees ban kee Pc Sapa Sait Ch ae: ee eee es } 3H) Ai Aes ONE. TGP ty RACE ga tty eos | Sin Raivetet. 1 elon 4 we” Ge am) NP WF ad ere ry, Ato fa Re VOR eee Pe vd) Fer fT) ‘ af ahs a re eo ee es ee ee Ra ae PEED OL WENT, WE See: OF Te ee ee es 4 yp N improve the situation materially, as the shallower angle at the tow point would reduce the influence of the disturbance. For example, at full scope, the cable angle at the vessel in the prototype system will be about 25 degrees. For this case, vertical motion of the tow point of as much as 20 feet will result in negligible deformation of the cable catenary unless the disturbance is amplified in passing down the cable. The latter possibility must be dnveatigated: Reduction in speed, when on short scope in heavy seas, may also help in keeping the peak loads within the limits of the strength of the cable. Fairing The possibility of effecting some reduction in the cost of the cable fairing by using a single-compound construction is discussed in Appendices I and IV. Results concerning the effect on stability of the stiffness in bending seem plausi- ble, but were not tested, since an available length of con- ventional, double-durometer construction was used for the sea trial. During inhaul of the system at sea, the fairing crept slightly upward relative to the cable, so that some strain was eiseted on the upper side of the hangers, elongating the holes in the fairing on that side of the hangers (Figure 10). To alleviate this condition, the fairing terminations were subsequently designed to hold the fairing with equal strength in both directions. 35 vaah ia J oe ; LES me «i Ween’ iess hhey At A i ail ute ve where ¥ j Db f iy hi ‘x e ny { ‘3 ate. » ee etal Ale. oh BS hae ‘he } ; r i Sa f , ; 4 $an ) we ve Ts ‘ ¢\ [ Js q 1h.8 Www Ay vult + jit : . ~ A) am i rT ae 1 | ri 4 7 ra ¥ +e ' H i a 7 te ien ’ j Ae eer Aint pe t ha a Duh te Of b ih’ 8 * be ae ee ihe! at ‘ * v =” oa ' " % : i ra > | i yj aid i Mine Me. Ws Condition of Hanger and Stop After Completion of Inhaul Operation The "ears" on the hanger point toward the depressor when the system is streamed Figure 10 36 The method of terminating the Dacron-cord reinforcement in a loop or eye, developed by the David Taylor Model Basin and the U. S. Rubber Company, was adopted as a less expensive method of attachment to the hangers; the Dacron loop is able to sustain the maximum load that can be carried in the fairing. Fairing Attachments The apparent lack of resistance to deformation exhibited by the mild steel fairing clips used for the sea trials, and the tediousness of assembling them to the fairing with the threaded bushing and "Nylock" bolts, led to the specification of a "Springier" material for the clips and assembly by means of rivets. This technique was used with success in an assembly of 3/8-inch-diameter cable and TF-84 fairing and resulted in a significant decrease in the time required for assembly. It was found that no intermediate bearing surface was required between the stop and cable hanger, so these were eliminated in the final design. Teflon washers used for such bearing surfaces during the sea trials were found to be badly chewed, and several were lost. The adequacy of the stop used during the sea trial was not completely determined since the steepness of the cable in the test installation precluded development of the maximum tangential load in the fairing. However, no failure due to vibration or neck-down of the cable was observed. Since the 37 prt one a + aid , s\n an oye design load is conservatively estimated and the load-holding ability of the stop can be tested independently, failure to test under worst conditions need be of no concern. Modules The present module is designed as a basic instrumentation- carrying vehicle. Only minor modification should be required to adapt it for temperature measurements. More extensive modifications will be needed to adapt it for measurements (sound velocity, salinity, conductivity) requiring a flow of water across the sensor. It is believed, however, that the present design can be modified to provide the necessary ports and vents. Handling and Storage Elements The feasibility of using the endless-track-type winching machine for handling the modules and faired cable depends to a large extent on the compactness of a unit which will develop the necessary pull. The tests with the Itwistle unit indi- cate that a coefficient of friction of about 0.2 between faired cable and tread may be expected. For effective performance, the winch need be capable of inhauling the system with the vessel traveling at a speed of only three knots. For this condition, the initial line tension will be about 10,000 pounds, progressively lessening with inhaul of the system. If we assume a margin fifty percent greater than the anticipated load, the design 38 Ai) J hd ; ie i ‘f ih ewe» whe haere inhi a at an Cs lal one 4 (tetera Gt Ie ad 29a shea ines Rab i by seal a Slebo. Akh est na Ss ea Dak “ne Ph Ray Pigaa % ii ktodn Miiseairine,, wild Ovbsny' ey eee." se aes sett ibid 4 wan rete 1d) dees ens ) q : J ¢ WO So, 6h) SAW es. sues else » f i e ne Obie & p beanies aed say Pek tet ee mar ts eis N qe alt 186 sien" + PASS. tit aes BEA a ia tacks Aiea Bey ca grant ae | Sei in, wai i ‘ a j ; are - Aang eke der Bs Bt tha He | 44 Bader) ace, oy fat yt i rs eee Eth ast wit? clerk nal Pee " Gr uate! 4 t dae by “i il AGT i‘ : 7 wWhahqas wun Bay ey Wk wcities ahaa? pers By ek ave, 214s Vie tien Gi 2 ie Bie shee | (fe ; Py he * rekil SLIM VERT sie 44 aw ce | att Wad oa Benen, Ine MRE A APSE: “tae wet, ty) vg ei Final yt a Ti sph, iy ‘Aye ‘bean Beers ae We tent Peake ghelegen ag Bele Sak at me ae cote oN seetie, wow | a aw pol Tes aes Laihy aie K bun “ioe Wiel wa ed bevsgith bile atti ir) a anes nag. eat ‘Vee ETE. WhO “672 OE sore a Filbw, ? ha tie? Wy Rua héid Bw FD Sorret acs aes fue ie wat peky sets ; pea load becomes 15,000 pounds. The normal force required to develop this line pull would be about 37,500 pounds since the frictional forces act on both sides of the cable. If we assume the maximum permissible loading over the total length of track, L, to be p pounds per inch of contact between track and cable, the length of track is given by re (8 500n tbs) P If a value of 500 pounds per inch is taken for p, in accordance with one manufacturer's recommendations, the length of track becomes 75 inches, which is about that of the Western Gear unit tested at sea. It would not be de- sirable, in any event, to reduce the track length used in that unit, since it very nicely envelops the modules while maintaining pressure on the remaining cable, as shown in Figure II-2. The total tractive capacity can be increased by increas- ing the allowable value of p. Discussions with cable manufac- turers indicate that it should be possible to load the cable transversely by several thousands of pounds per inch. Hence, if the track and fairing materials permit, or if other suitable materials can be found, it appears reasonable to retain about a six-foot effective track length and increase the tractive capacity by increasing the normal loading. If p could be increased to 1500 pounds per inch, for example, the winch could sustain the maximum pull imposed by the cable. 39 biG) i) i iy he 7 ig ; os Bs mn Cheick "a wi ea sou as ca FOR CH NObeti wen : ¥ rhe gil iy ee Ria ett TE — re RADY wail, hd (vay nl oe ih Aap et hy hava any sda as 4h hana i eee ahaa si en Lae “ae: Veer oan 7 ‘ Vast 1 ~ is mel Ne Gr we int Bi: ot ae | a ; ; ; sf i Aint ; ‘ x a uy SF ra i f 4 ’ 4h AG 7 ' im ; 1 ee ‘ti c) 1 rane a i f hs Wi ki : ee rd ve card bi aor , aa aon me be ae bs i i wis gL ap Anirapealt eet ne a 7 ie 2h Aerts Mave Nik itt sett a yeolhaael ire, te gen oe ae © eigen ihe. re oa a rt y, i : Ve way User he galt ep on wi Bits al ital nl ‘ on a Sune pie. wae Be; di 1 ae ba a" ” habit fon | | al ‘opaite Bh eS by ey ia, rts, eee “ Re i pine! te ee Wa, Baeer bond a et ny wine i iiebe Uae wei | eos: i * - “a8? hiwe veh dis fy, at ne ea ee, ae ais “ ote aut Sa pits saad HLH S i! ai itan a ae cena a shes ‘el ae bere Ts oer. mona aed brs iain ao: err wc Shires y mn and Mandi oi Ghie: ‘) st alll a th ai oo seh bid 4 1. ge ty. ‘> ye ry binmeend 4 ; oy) a mn Bh i One caution must be observed if very high track loadings are used, however, since a module in entering the tracks is subjected to a force tending to expel it due to the geometry of the entrance, although this force may be minimized by tapering the end of the module as was done with the dummy test modules in the present design. This factor does suggest that by designing the lower ends of the module to maximize this force, any module could be used to sustain the load when under tow. For example, if the winch were capable of sustaining 15,000 pounds through the tracks and an additional 10,000 pounds could be developed by the aforementioned technique, a 25,000-pound loading could be sustained with only a 10,000-pound load on the cable fitting in the module. The track-loading technique used in the Western Gear unit is nicely adapted to englutment of the module and appears to be superior to other methods. The problem of passing the module over the stern with equipment of reasonable size is still in the conceptual stage. The cam technique described in the preceding section seems to be the most promising approach since it appears that this technique will result in minimum size equipment. The most promising approach to the storage problems seems to be to reel the fairing loosely on a large drum, letting it overlap the modules as required, and to level wind by moving the storage drum transversely relative to the winch. 40 fw aes Rohit eree. i bach wit eat ri rid, Bi aia iP me wigeor Sel ph ede Wy Oe mmeee: hel ‘pahe an Bey A Be ne? te 3 CHE oh. Gye pb socee ee Ake ep aaa shite i Oe ee ee tt younem ty bag or Gh) ATAe ih how ad) 6 Cee aa: ‘wri, ie onniaed | per OM, seem denly wh i eho ‘wale - — ¥ he. : i Nia are te j | ii a 7 a, 4 : ay pa) iM feel ail Weta eet TO oat) hee ama a seis me? owl ee eat { blithe viene jakonissat Wink ae hitaney ae fat Nhat en a - it hee i at ae ts. Marne tw 4 he Hult & i’ wn ose | i WoO ak Wher oad, 009 > ae abeckdain Pia vB ia ee a sala i” hei layhly a ‘thicliys anne Og OR wk ‘ote oe ue en e5 eta ote eros = Ub ded A Ses Past 2) a Fe vin He es itn: Pooh sediment ie fag NA esi saga 49 aba leanings gs 1 A Cane Ha nse amid a ei. ae es ie i » Mh Lae: io a 8h a a (ge oye — bay ft nt Ete hn ae Hs: wae Mi ¥ a ie ud if th ’ : ; Bee, in faihi um imi ba) iif sith: Way sires, et 2 i a # a Nerd MA NR | toy bee aia Sa hah "ee i yi ie al weg wx rth : is sig Pept # "4 UE vy ores sina ane ne fay We BR it sty?! ane > sists ors we oT ny tn ee ie, belitw Hea nai BL Paevirctay eras aie Oe ee ee | wea taeto Ane Ahk: bi hile, table caiat eh ashe at peels ba et se avid qmemn tiers 9 ii preg and ade) aR A ag yee Me ft a pete mi vor: i se of 8 es & vee ca buy it cael | oN # Ait sin hyn Tass Pee He AES OLR AN LEY VA STP eS Be os LS abh, | MSE OU aa ee ee a ee | CONCLUSIONS The hydromechanical feasibility of this cable-towed oceanographic instrumentation system has been demonstrated. Analysis indicates feasibility of attainment of the depth objective at design speed within the limitation on maximum line tensions. The limited evidence attained is basically favorable and lends assurance that the predicted performance can be achieved. The hydromechanical performance of the towed elements, the results of the tests with the endless- track-type winches, and the conceptual solutions to the handling and storage problems were satisfactory. The feasi- bility of the "in-line" module concept, providing a flexible arrangement for varied distribution of instrument containers in the vertical profile, has been established. 41 aS Ms pati 4 +O is ii Hebathavat i oh la wie at Pos tg ie ml pene, dhe eA eabied a Sr 1 php ase of ol ' ue ; ‘a Boas: al! Ge? Tihebs See RO gyi ‘ wi Apia Hct a ‘ f o | ‘ Ren) de dt, Ana * ee RL npadey nine o oi. ee even iy , ay a Cae een ee EU rene! ethane yas Tas bt alt nae Pict ‘ait, ) ponnate St 8 Dey a ON ee, ni, mls wit ovine tent a ; ij , ug i, = Ph A Ya ee We er ee me a ek ae ‘ he ve a wh WP, eedeee —farviletived ba ‘ oe Mi ae ee ay i shy il ha poe oh 7 iP ob Ae i ‘ dake ¥ ‘A ail sf iat “a Ag wien a tei * - bed sal tne “F iL yee a ¥ } ow ‘Sg iota whiny sieesitt } hut mn ‘ ti oN eA ; [ Pail mt Ein aie pati fy ; ial Sy “4 : =i ar haem | eas is i sca wie we iby : e ce + ka i we ‘Se a i a ¥ 4 ae a nN, canis Sie 5 i a oi a ¥ we a i Be Jf tate Nae "ia ; Sea ; ope * ire sai lpea ak ; bisshh ikea evn via: aul’. \ alter a ont, an i) wa ie 7 . j : = al 7 % - 7 ¢ ¢ : q ? 4 RECOMMENDA TIONS With the hydromechanical feasibility of the system established, and much of the design of the towed elements well in hand, it is recommended that development of a fully operational system be undertaken. It is suggested that this be accomplished in two steps. The first step should consist of design, procurement, and evaluation of a prototype system which would include representative oceanographic instrumentation, a full-depth towing system, and handling and storage systems. Selection should be made of a data-transmission technique, with a preliminary choice of sensors. Electronic components should be limited to those sufficient to provide a comprehensive test of the electronic system. Emphasis should be placed on the measurement of sound-velocity, temperature, and pressure at this stage, since these appear to comprise the areas of greatest interest. The second step should consist of procurement of a fully operational system tailored to the needs of a particular project. Practically all the material procured for the prototype system should be usable in the operational system. Since the cable fairing represents a major cost of the system, it is recommended that a 20-foot length of the 42 i ' ; ves ty i ‘ i! | te i“ 0 ade heck i) i} a e Le . hi 4 aa ery iT ati an nid a nd) fe pps sao hott ig bah ua Kt - | aa te i fan ie | ate mid ir ok . ae jis ale as | sia eta ) i, en oe ois _piteote vat i» a above noi ‘sade ee | 4. Ne, why | inv ia it a aaitine enna: ih, i may Pa | breed FER cat J a3 <4 snd cea ath (8 ba | ihn do ie ee) dibertas x08 - a heey a ff ‘ ) i ww ur an j 7 | Gar! a) a aS) a sh a car Ry SO ae nee sSingle-compound fairing be thoroughly tested to establish its adequacy for application to the prototype system. The problem of surge loading should be studied further, and techniques for effecting reduction established. 43 APPENDIX I TOWED SYSTEM COMPONENT DEVELOPMENT tga ase i ¥..! a Par se ia i Ahi eae ls APPENDIX I TOWED SYSTEM COMPONENT DEVELOPMENT GENERAL Details relevant to the major components of the towed system, including requirements, design approach, develop- ment, and resulting characteristics are discussed in this Appendix. DEPRESSOR Requirements Based on the analysis presented in (2), the depressor Was required to provide a total downforce of 4,450 pounds at a towing speed of 7% knots. Since its only function was the provision of downforce, it seemed reasonable to require that the depressor be inexpensive. Design Approach The total downforce was developed by a combination of weight and hydrodynamic depression for the reasons dis-—- cussed in (2). The following specific objectives were established: Weight in water..........-..-.-1,000 pounds Hydrodynamic downforce........3,450 pounds Arctan (downforce/drag)....... 2 84 degrees Development | The detailed design considerations involved in attain- ment of the objectives stated above are given in Appendix I of (2). On the basis of the work reported therein, a proto- type design was executed and a full-scale depressor fabri- cated and tested (Figure 3). The depressor was test-towed from the No. 2 carriage at the David Taylor Model Basin. Towline tension and the cable angle at the depressor, relative to the horizontal , were measured and recorded as a function of tow speed. The first test demonstrated the depressor to be hydrodynamically un- stable in pitch, thus making it impossible to control the dynamic downforce. For the second test, the effectiveness of the horizontal stabilizers was increased by adding stabi- lizer area and tip plates. In this condition, the depressor was towed at speeds to seven knots and found to be stable and responsive to tximm adjustments. The results (6) were corrected to standard sea conditions for design trim and are given in Figures I-l, I-2, and I-3 which show, respectively, cable tension at the depressor as a function of tow speed, towstaff angle as a function of tow speed, and cable ten- sion at 7% knots as a function of horizontal trim tab setting. pe WE Panta aap li / hana hh Been ale . eas rl slp ie ae er SEIN igor a wr igs 7 wit 1. Ae ab ote 5) Cy ey a) oJ wap yes te hig ees MN ie i wi OMe ei. ee Daan Fo A hue WE lie. lip NRE TREN EE va eR he % i ‘ KG H Ral! ye DiC a f Su Went zi eat ued ay Dana Ed ye AB " Pee) Be i" quid Bie We rae Bg * wl) gs hy a he 1s my Pe oats ah i yk i if ign MI aa co. LBANENE & ———_—___- oC | —-— yao. 10 can =O THEIL aNCH —RRSOT- ——! KEUFFEL & ESSER MADE INS A A eae oe ee Maa ee = ieee ie (aka a : pire hy i q = be rita iN ar ; Ad eh CL wa + Nari aire 7 | har nfs up) La hind oe ve ; a Ae 4 decd erie hiieaes ot Thi pts Hil he iy bale bles saith me Mh: ais yeien @ ANANVEly "¥ S'o NIGOVA "OD HaSssa 8 1345Nay Ee a LL-L6GSE HON! 7 AHL OL OL X OL , 2 | rae i oy a isi es uta eon ee eee | Blaster [sar ednd eg G aes asa i 3 bei Fecests Bfatagt ets rears.) 6 SIE naa geae ved inerrant feces { D | > T¢ ns! OF BEV e ped _ | |Depressor As A Function [jeuevdtor meveang [i ee ‘ah cl hi eed 74 am | tome Say ae a Fh a - = i Aa hey f th " ‘ ps tas Re Nadi | ish sa Se We may, therefore, conclude that the contribution due to bending is negligible in comparison with that due to axial loading. Substitution of a homogeneous compound for the present two-compound construction should have virtually no effect on the location of the centroid of the externally im- posed forces, since practically all the load is carried in the Dacron-cord reinforcement. Long sections of the two- compound-construction fairing have evidenced no instability while under tow when excessive stretching was avoided. Sub- stitution of the single-durometer construction, then, should result in no adverse effects on stability. Selection of Length It was desired to minimize the number and size of stops to avoid problems in reeving over drums and sheaves, and yet eliminate excessive stretch and bunching of the fairing near the lower stops. The selected length represents a compro- mise between these two goals. The elastic modulus of the fairing was estimated on the basis o£ the experimentally determined characteristics of simi- lar fairings, which indicate that the product of A, the area iy CLoss section, sand &, (the modulus tof elasticity, 2s about 12,000 pounds. ¢, the strain under the load T, at a point, v! ca phy * “ ro , anes di p Wy is ay ie Dei it ee pwd) i ae ras np > wn one eS ee | | mary? & dana hii! Aart Ost BAA eh 4 haa Lig ain 7 - i i a na 4 A aL i bia ae aad Wile pated heb beans ay fad hit wie i a Pociers and: . sfetihsh a | 7 i hy Dw é y 7 S > Au ay i Cay ! 1} : y 7 / : ' : po Bie, Y ig He PY 4 2 hash i iy T, wy! i a we : | wenn : s, from the bottom of the segment of fairing, is given by T SED ‘ where L dT T : qs 35 p (o) and L is the total length of fairing involved. From Whicker's work dT ag 0.67 lb/ft f when the cable is towed at the critical angle corresponding to design speed. Hence, § , the total extension in the length, L, not greater than L 0.67 lb/ftt Le ONG b/ Ete § = | ZA s ds = 5 ty P fe} with an assumed fairing length of 200 feet, the load at the upper end would be about 133 pounds, and 133 lbs x 200 ft ——T3-000 ibs | ~ 2-11 £t _ ot SS or about 0.5 hea ae of the length. In actuality, the fair- ing elongation will be less than one-half of one percent of its length because of the assumptions previously mentioned, and so it was concluded that 200-foot sections of fairing should tow satisfactorily. I-16 Re ye Me et CEO at Fic ioe Lina Lue TS Das peat el 28 patil) taeda Lop “ind wre i sete wi; ® 17 AAG a tia AGy Lime ba sie eiianvead, a: je, he, sel ania ts nativbone fool: aos, ah ip ci taedgoed nen ie i) sae ry 2 _ibtegaatnet hint Characteristics The fairing will have the following characteristics: Resistance coefficient = 0.3 EA = 12,000 pounds W Breaking strength 1,200 pounds tl Maximum length 200 feet Construction 40-to 60-durometer neoprene rubber with 6-ply Dacron- cord reinforcement v Weight in air 0.67 pounds per foot W Weight in water 0.17 pounds per foot INSTRUMENT HOUSING Requirements The general requirements for the instrument housing are given in (2). Since the tension in the cable is maximum at the top, decreasing with depth, and the hydrostatic pres- sure is at a minimum at the surface, increasing with depth, the forces acting on the instrument case vary according to the position of the housing along the cable. The end caps of the housing, being free-flooding, are not affected by the hydrostatic pressure and are subject only to the tensile load imposed by the cable. This is not true however, of the cen- tral, watertight, cylindrical compartment which wiil house eL7, tion ee de, sin, ise as. baie ; nae Beck lL vesgia s') musts va ue on wh ig vive ae WA MERON ADs, AU Re!) PSE Ste cy 1m nec anace eae TA PAGE as a? ay og the sensors and associated electronics. This section of the housing is subjected to both an external hydrostatic pres- sure, acting on it radially, and an axial force. This axial force may be either tensile or compressive depending on the magnitude of the cable tension at the housing and the hydro- static pressure acting on the sealed bulkhead located in the end of the cylindrical instrument compartinent. The housing nearest He surface, then, must sustain the highest tensile loading, and the housing nearest the depressor, the greatest compressive loading. However, to facilitate interchangeabil- ity, it was decided that the housings should be designed to sustain the maximum load, either tensile or compressive. Since each housing is essentially a connecting link in the cable, it was decided to design each te withstand a load equal to the rated breaking strength (45,000 pounds) of the cable. The maximum depth attainable by the housing nearest the depressor would be, at zero ship speed, just the length ef the cable. With the original estimated cable length of 6,200 feet, the maximum pressure on the bottom housing would have been 2,795 psi; with 8,000 feet of cable, the latest estimate for the system, the maximum pressure would be 3,556 psi. fh +H yy ne ‘a j iby OW Ue a bike Oya “ow i porbreisigs a sa aie air ij hea. f ys Ae ee Design Approach The first instrument housing designed to meet the above specifications was essentially the same as the housing shown on Page 43 of (2). It consisted of two tapered end caps, each housing a mechanical cable lock, threaded onto a central instrument section. The electrical leads from the cable were sealed by a potting compound, which served as an electrical insulator as well as a watertight seal. The threaded section was sealed by neoprene O-rings. On each end of the central section, a phenolic plate, containing the female receptacles for the electric feed-throughs, was held in place by snap rings. The center section had an inside diameter of approxi- mately three inches, a wall thickness of 0.345 inch, and a length of 12 inches. The overall length of the assembled housing was 28 inches. Development To test the housing, a fixture (Figure I-5) was designed Which, when enclosed in a pressure tank, would subject the housing to tensile, as well as hydrostatic load, thus paral- leling operational conditions. The first instrument housing (2) tested in this manner failed, due to the porosity in the compound potted around Test Fixture with First Instrument Housing Rigged for Test Figure I-5 i by i we Yap ; my SN SNES? ian a me the electrical terminal leads and the insufficent bonding of the compound to the adjoining wall of the end cap cavity. Water under high pressure (2,600 psig) entered the housing through the cable armor wires, ruptured the bond between the sealing compound and the end-cap cavity wall, and extruded the compound into and around the phenolic plate mentioned earlier. Since no evidence of failure of the mechanical cable lock in the housing was observed (it had been subjected to a tensile load, under water, of approximately 7,000 pounds), it was decided that a test should be run to compare it with a poured epoxy fitting of the type used successfully by the David Taylor Model Basin. A poured fitting of this type was designed in the form of a clevis for attachment in a ten- sile testing machine, and a comparative test to destruction was run. Failure occurred at a tensile load of 17,300 pounds. The rated breaking strength of the cable was 18,000 pounds. The failure occurred just inside the mechanical lock, approxi- mately 5/8 inch before the first bend of the wires into the spool. Three wires were broken; examination revealed a "necking down" indicative of tensile failure in the wires. After this housing failed to maintain a watertight in- strument compartment, a "test" housing was designed speci- fically to test the sealing characteristics of commercially available watertight electrical connectors. I.21 ghee hd iia ef a aa a as One method evaluated was a packing-gland-type fitting which seals by squeezing the insulation of each of the indi- vidual conductor wires. Although a pressure test indicated that this fitting successfully sealed around the conductor- wire insulation, it was discarded as its large size would have required lengthening the housing thus increasing the handling problems. It also provided no method for discon- necting the cable from the central instrument section. A more compact design (Figure 6) was selected in which small pressure-terminal seals, screw-mounted to the housing bulk-head, may be utilized. Also, a more compact clamping arrangement for securing the cable armor wires to the housing was evaluated in the test fixture, as shown in Figure I-6. A hydrostatic pressure test (2600 psig) of the assembly revealed no leakage around the terminal seals, or any slip- page or failure of the armor wires. This housing was used during sea trials. WAT O RE CORTE he ee oT 4 NERA ENT 28 JT vid yy Aa OL ne ea a eb .% Whe? dial ae Aa BR) i hal na we on? pe edieeiay Abi Mg sas tier MRP a le bene? v8 fae Ds Bees eh manne’ ete Bae Bese ae ca Ae) EEE rend oe hi i Dae : eu) Sisentih wate oe wert vowed 83 hth: Hen th ‘eas Sy wy eee il eh We a a pia. bee doant Wan rditen ss © oe Sai “Sew Pia Wie ee AR ¥ LAW hired hay Siteag US NAVAL RESEARCH LABORATORY WASHINGTON 25.0C¢ ee | INSTRUMENT MODULE MOD IV SED SK-1197 DIM, 5° DIA 27” LENGTH WGT 50 LBS PURPOSE - HYDROSTATIC LEAKAGE TEST -RESULTS- | am Test Fixture with Test Housing Rigged for Pressure Tests I-6 CABLE STOP Requirements The towed cable fairing is subjected to a force (the tangential component of the hydrodynamic drag) acting along its length. To prevent the fairing from sliding down the cable under the action of this force, the fairing must be attached to the cable by a free-swivelling attachment. The attachment must grip the cable with sufficient force to sus- tain the load even under the condition in which the cable, under load, may reduce slightly in diameter. For design purposes, the maximum load requirement was based on Eames' loading functions. The maximum load required to be carried by the stop was thus taken to be 510 pounds for a 200-foot length of fairing. Design Approach For ease of assembly to the cable, a split-ring-type stop that grips the cable by means of friction, was developed. To allow for possible reduction in cable diameter, a resili- ent liner was selected which, under pre-compression, retains enough normal force to develop the frictional forces required to sustain the load. Because of encouraging results of DTMB tests of cable stops lined with sand-impregnated polyurethane, this material was selected for this application. I.24 Wi ax e ie Cheha iy. . : ey A us oad je i eign ey ork beied Mitty sh ¢ ce Ws ie mee - Rk Pecme i ae has me sa init, Y avaesialiaal a evi. ; a i yr ¥ 4 W chine Bene Ohh eal ys yf ame Tue” 1 pees ‘Gh ie ys ai) ' r ul, hae ae ane ae 7 i 4 Pye i ‘ a ete Bien tince as ee te ; eg panes ye 4 Lae ae Shgoterah Wi mE i. beats) ae oa whee a paste WAR a | nat west ane BN a, as F ne (sotaial p oo Sus iuges eerie) Lainkie ox wth mii tonne q mad xO Pinner vilbpayiosire my cL Lulu roa ntter ves ertg Xoy basa yar ne ie sal tek pee vk ames 1 ied Oo Phe basil Ber: yok bade cul hal inuresae we er as A test stop, utilizing a split ring which grips a 3/8- inch diameter cable through the liner by means of three socket-head cap-screws, was accordingly designed and manu- factured. For tests, operating conditions were simulated by loading the fairing and simultaneously exerting a load on the cable. The stop was tested to a load of only 400 pounds, however, due to the limitations of the test fixture. 1 5 Zaks) a | wd Sc" item, va i 4 ee ‘doa pat 2 HANGER Requirements A hanger, mounted at the top of each 200-foot length of fairing, is required to transmit the hydrodynamic drag on the fairing to the cable stop. This hanger must grip the fairing firmly so as to sustain the maximum load without damage to the fairing. For design purposes, the maximum load was taken to be 510 pounds, the same as that required of the stop. Design Approach It was decided that the terminal clip must attach to the load-carrying member of the fairing (which is the Dacron cord- ing) in order to prevent tear-out or rupture of the fairing. A design was conceived (Figure 5) in which this was accom- plished by means of bending a small length of the Dacron cord- ing, from which the faired section had been removed, and gripping this cording in a clamp. Additional clamping effort was achieved by side plates which clamped a length of fair- ing approximately six inches long. The developmental clamp is shown, attached to a short length of the fairing, in Under test, this device sustained a load of 900 pounds. During assembly of the cable and fairing used for the sea trials, all terminal clips and stops were subjected to a 300-pound proof load. Oh tir at abe. SNR BARS Lt ah i Wk ae a oy A ie aR An) Lon Hr | em AP diebae ieee A ae ir oli aaa i i an os *: binds 5h sha ie, ieee ne ia on Veep te barons mane iy wee eben a ‘oie al : ia ly ual Ansan Cimonk, one ya) lsitind m pate ioapaenncet ities bike Ye vee wea i bette bey a OC ae ees euro “ a aC Lee a i : a at 4 he bani # ben aanne to dist oer atin welor 48 bond twa Re) ba’ - atebaa ies, Xe tea bret Developmental Fairing—Hanger Attached to a Short Length of Fairing Figure I-7 yen et ae Z ar faa 7 Mi ius Ui Ph els a a SAT Dian Although the hanger described above performed satis-— factorily, it was obvious that reduction in fabrication costs and assembly time could be effected if the reinforc- ing cord in the fairing could be terminated as an eyelet. As mentioned previously, this proved feasible, hence the hanger shown in Figure I-7 was designed. acs. ee / APPENDIX IT SEA TRIALS 26ib oat : Pee ey ye NN FO oan Ae, Ae , ii; ayy rte evel agen prank APPENDIX II SEA TRIALS INTRODUCTION A model of the towed system was tested at sea aboard the U.S.S. YAMACRAW (ARC-5) during the period 13 to 17 April 1962. The tests were conducted to establish the hydromechanical feasibility of the system. For this purpose, it was considered necessary to test only selected full-scale elements of the system, and to provide only enough instrumentation to define the operating characteristics; a single pressure sensor located at the depressor seemed sufficient, provided measure- ments of cable tension and tow-cable angle were taken simul- taneously. DESCRIPTION OF EQUIPMENT General The towed system consisted of 1,200 feet of cable (the lower 685 feet of which was faired), a prototype depressor, and one test module. The handling and storage equipment con- sisted of an endless-track-type winch, an existing storage reel, an existing stern sheave, and miscellaneous fairleads and rollers peculiar to the specific installation. A tensiometer, depth indicator, and simulated instrument module were also utilized. II.2 Cable Cable of the desired type was not immediately available so two existing 600-foot lengths of 0.782-inch diameter, double-armor, 35-conductor cable were spliced together. One of the cable lengths had been previously rejected due to cracks in its insulation. After a hydrostatic pressure test, eight good conductors were selected for splicing to the other cable. The electrical continuity of each selected conductor was checked after the splice was completed. Fairing and Clips The fairing was a TF-84, sized for 0.782-inch diameter cable, produced from Bureau of Ships mold No. G-60818. The after portion was constructed of 30- to 40-durometer rubber, and the leading edge of 50- to 60-durometer rubber. The line of demarcation between the two compounds is visible in Figure I-4. A six-ply Dacron cord, capable of sustaining a maximum load of about 1,200 pounds with a 10 percent elong- ation, was molded into the leading edge. The fairing was attached to the cable with clips spaced on four-inch centers. The clips were made of mild galvanized steel and were secured to the fairing with "Nylock" bolts screwed into stud-type inserts passed through the body of the fairing aft of the Dacron cord, 11e4 3) vs _ a: ito grenr ag, pitas lth rows a v4 a WK ie! a eh ral i: iy ae heat ake bs a ce HN oe Pail: ita’ tt “ga parienad F ‘pvinallpssndalt werent vei ” ‘hava vow a Mare let arty! ism Be ‘pkey, ia nee Can Wy as illustrated in Figure I-4. The general configuration of the assembly may be seen in Figures II-3(b) and II-5. Hanger and Stop The hanger and stop assembly is shown in Figure 10. The clamp permitted termination of the tangential load in the fairing in the absence of a loop in the Dacron cord. The split-type stop, described in Appendix I, was used to transfer the load from the fairing into the cable. In this installation, the Dacron cord in the lower section of the fairing was clamped within the downward extending ears of the clamp. ‘The upper section of fairing was secured to the clamp only by bolts passed through the rubber after body as shown in Figure 5. Instrument Module A development module, described in Appendix I, was modi- fied to function as a towstaff by the addition of a clevis, a sheet-metal fairing, and a bail for use in launching and retrieving. The module is shown in Figure II-1 installed on the depressor. The handling bail may be clearly seen in Figure II-l(a) and the fairing in Pigure II-l(b). The depth sensor of the module was mounted on the end plug as shown on Figure 6. Ir.4 “ barat ban HOC went ne we “he Wy 7 7 ie whi tel ate a ie sae oa aiid da ghee ir , , Mt PASAY, aoe a ree ae Ly seth. | A : nee hs, ed ait i fine ene wh srs ssh scien Ridin ; is ren waLdmaynd tox pare Kh cre o * nina em a ms on at sion ciakets he bay ey st 4 a eet bos b wpe nt pe rh ak ap ‘ Fadl : ; bem, utd ge ne Yagi Haat wtaben md ot Depressor The depressor is described in Appendix I and shown on Figure 3. Instrumentation The instrumentation consisted of: he A Bourns Model 304, miniature gage-pressure transducer which converts pressure into an electrical output by moving a wiper contact linearly across a precision wire-wound poten- tiometer; 24 6 A bridge circuit for the Bourns gage, designed to permit reading of gross pressure and fluc- tuations about a selected gross pressure; Si A two-channel Brush recorder, Model Mark ITI; and 4. A 20,000-pound-capacity direct-reading Dillon dynamometer. Handling Equipment The handling equipment consisted of five major components: L. A conventional stern sheave, approximately five feet in diameter; 103E 6 &) oti ee He ale aa ts sais Py: vem ge meek iz. ito i A Western Gear "Cable Hauler," Model No. 1142, as shown in Figure 8. The clamping force in this unit is developed by means of three pairs of opposed air cylinders and is transmitted to the tracks by means of three pairs of opposed bogies, as shown on Figure II-2. Since each pair of bogies moves inde- pendently, englutment of lumps by one pair does not affect the clamping action of the others. The entire upper track assembly rotates about the for- ward drive sprocket. This arrangement, coupled with the independently suspended bogies, provides a means for accommodating large discontinuities in cable diameter. The unit is hydraulically powered, and is rated at 10,000-pounds line pull at 50 ft/min on jute-covered cable. It was modified by the addition of entrance and exit guide-roller assemblies to orient the cable fairing properly, as shown on Figure II-3; A fairleading system consisting of roller assemblies and a trough which guided the fairing to the cable well; A powered storage reel mounted in the forward cable well, equipped with a variable-speed drive system and band-type brake. An associated fleeter was mounted just above the reel, as shown in Figure II-4; and A davit for lowering the depressor over the side. II.6 fhe en's is ee ‘@akagtid: ey ie coe Khe re nade asi? tev ‘ Pt Hee Me peters.) wh In ate eLoud naay anu nya ‘Beek gueihttnd Las ime wie Tedwett a sdwonnall bs hie 2% ote AA eden ‘if Lore oe invedu! ae i, TEST INSTALLATION The installation was tailored to the accommodations available on the test vessel. The winch was mounted near the stern sheave (Figure II-5), and the cable led from the winch by means of a roller and trough system to a large powered storage reel in the forward cable well. The winch was mounted with the open side of the tracks facing the starboard side. The centerline of the tracks was canted relative to the centerline of the stern sheave by that amount required to make the extension of the centerlines intersect at a small angle, in azimuth, at the location of the vertical guide roller mounted on the after end of the winch. The winch was thus placed in a bight of the cable, so that the load on the cable tended to force it into the tracks. The after guide-roll assembly is shown in Figure II-3. The two horizontal rollers serve to orient the fairing for entry into the tracks; the upper roller is hinged to permit passage of the stops or modules. In operation, the trailing edge of the fairing is turned away from the vertically oriented guide roller (Figure II-3(a)). The cable is shown, in Figure II-6, passing through the forward fairing guide rollers and about the forward transfer roller; from the forward transfer roller to the cable trough in Figure II-7; forward to a second set of transfer rollers, Figure II-8; and thence into the cable well, Figure II-9. II.7 lan. bash: all ae “pee eth —- ee Nk ate aay! se kinieatan Faia os ‘oa atv. ae avert ro) 8 i? eae clay Pete! eit @ hy Beh i st : ay ane) pe sate Aviawes Bs te | hit Syke oS x08 bed th wae u 7/0, eae oe vm eee a6 ois me i ¥] hein oe ier Cn | eae Li eae ashy Balin De he ite wal, bial ‘hat ™4 men aenae: Ce le ein une a ea 4g he apts” cP REE SS Di Lah ma yl caper ann tree LF} ‘st aoe aaa mitt at" Nites Mes ei le} ue Mihtra ti wiki Ee eT eT ee He : : as iug oN yO ae sai : oie Bebe ay vane oe ave ah evs aad ie bere Pye ee) Deel, aeih fs Vee by miele : VRE wn gd id, povanta ay aririga yeas PAR yt! Anon, BOE BT: sO her ay 1 hw vt by -abeag wid / a aa AL ane bese 2 ri The electrical conductors were connected to an existing slip-ring assembly on the storage-reel shaft. The slip-ring leads were led to a nearby laboratory in which the recorder was installed. The depressor was placed under a davit on the port side of the winch. The dynamometer was shackled to a pad eye on the after end of the winch frame, and thence to a wire rope shackled to a cable clamp. PROCEDURES For launching, the depressor was lifted over the side by means of the davit and lowered until the load was transferred to the main towline. An alternate procedure consisted of using an available ship's boom to place the depressor over the side, transferring the load to the main towline which was kept on short scope so that the depressor was suspended in the space between the bottom of the stern sheave and the waterline. Anti-sway lines were attached and the depressor thus carried to the launching area where launching was accomplished by merely paying out the main towline. For payout, cable was pulled by the winch off the storage reel, which was braked to prevent slack. For in-haul, the storage-reel operator attempted to synchronize the storage reel with the winch to maintain II.8 Bhasin es a Hbatsors we vem ajakn We ene’ ai au li a aad é Misa ten He io oe et an ancy er i ei, D joa, LP av a4 di y a td ba tain fa iow, i adad Pre ay RAMI om tension in the towline between the winch and reel. The "freeness" of the fairing on the cable was checked at the stern sheave during payout, with manual alignment of the sections that did not swivel freely. DESCRIPTION OF TESTS The winch was specifically tested to determine its capability for englutting the simulated instrument module, in-hauling and paying out the faired cable under operational conditions, and developing the predicted loading on the faired cable. To determine the first item, a length of 3/4-inch-diameter wire rope, with an attached 1,000-pound weight, was rigged over the stern sheave and led forward between the winch tracks. The simulated module was then bolted to the cable between the stern sheave and winch. Tests were conducted by causing the winch to in-haul and payout the module several times. These tests were conducted in fair weather with dry equipment. The second item was determined by observing the action of the winch during tests of the towed system. These tests were conducted in a sea state between three and four, with almost continuous heavy rainfall. To determine the third item, a length of the faired cable was attached to the dynomometer, which was shackled, in turn, to the stern sheave, and the winch was engaged so II.9 i ay : teas vee ‘ 1” ~< 2 Z - Hg? ae i - (on wien a ry f rp me i mi We ty Se ne AD: De pry Paly ee "4 ine eee My sage ery vi EERE A aa eee Dui Tari ae Wve dan aM * a PME AND Rint igh saa eh Vea sual kt oe PW RW, fi tae A i. hy we, we eve tnn cele Pe ». isha? yi AP | a ite Aen 4 ay a ah ae wilaty & 4 a joe) . , ail ¥ eae Ment wae ere ae as to place a pull on the cable. The air pressure in the loading cylinders was maintained at 110 psig for this operation. The tension was noted and the air pressure in the loading cylinders then slowly reduced until slippage relative to the tracks was evidenced by a decrease in the cable tension. As the winch was hydraulically powered, it was possible to maintain a steady pull under fully stalled conditions for a short period of time. These tests were con- ducted in fair weather with dry equipment. Tests of the type described in (3) were not run, due to lack of sufficiently sensitive pressure gauges. For the tests of the towed system, the depressor was placed overboard and launched on a short scope of cable at a ship's speed of three knots. Approximately 100 feet of cable was payed out and the towing characteristics observed at speeds of three, six, and eight knots. The cable scope was then increased, while at a speed of eight knots, and the depth of the depressor monitored continuously during the lowering. The pressure signal was lost, however, at an indicated depth of 420 feet. The lowering was continued until 700 feet of cable was in the water. The ship's speed was then decreased to six knots and the tensiometer attached to the towline. When the speed was decreased, the pressure signal was regained. The tow was continued at six knots. Depth and tension indications were recorded and the angle of the tow cable at II.10 if I I Wa | ; a | . Lt an De ma werk ng eu we hi zi Wied aid blag ean mre a he wenveimo Hin. at honh Rae ba. i | ar ape mad, ae Laake une ee | aD caer eon a bir _ QO ae bs Ben wl ieignd Rene ; nish) aie Gee iwitt By ‘erate halbiniee aul a ee me few? at ise ' ‘ ri : oe it Pia Ta A i aor pee cnet Aydt votes r oy er hte: Leo dines et fa er eee wt ‘cena wer Salome np ogian) baie) ey . peters wSiing! gi ~ ha Pri, Fortin eee eave Meas Ess On 4 ae ait aut ine A genio Rete «Get Nagy j We Py aes wheleaenae Sls Sit a iki aha a dai ¥ | inde om) nee win fans oa pene 1 Beegs # ‘theta, War Me ‘nw n° an a SAtL ase Sh yew LWyied wits at rota KAY PE en ee Auld. DR Ra RR RE PHL i | Mitt | ih u 3 HPA Gua 8 a hag ae a F a ha ga ane a ‘ga; houinnanian nu we ace, eed ashe: bh pat, wie ete bea ieane, weir the surface was measured. Speed was then increased to eight knots and the pressure signal again lost. Tension indica- tions were recorded and 90-degree port and starboard turns made with a standard rudder. Speed was then decreased to three knots and the tensiom- eter removed from the line. The pressure signal was regained when the speed was reduced. The system was in-hauled and, due to a difficulty with the storage reel, the cable was flaked-out on the deck ahead of the winch. It was noted that the depth signal was lost when the spliced section of the cable traversed the stern sheave and was regained when the traverse was complete. The in-haul was stopped at a cable scope of approximately 50 feet, and the system towed at a speed of six knots toward sheltered water. While towing at six knots, the cable slipped relative to the winch. Speed was reduced, the tensiometer attachments (without tensiometer) attached to the towline, and the tow toward sheltered water continued at a speed of six knots. Retrieval was completed after reaching sheltered waters. After retrieval, the cable was flexed, under no load, in the region of the splice; it was observed that the pres- sure signal fluctuated and was occasionally lost during the flexing. The signal was regained and became steady when the spliced region was straightened. ig3e 5 Jbdl RESULTS The winch englutted the module without difficulty or adverse mechanical effects. As shown in Figure II-2, the flexible tracks conformed to the module and maintained con- tact with the cable over nearly the full remaining length of track. The faired cable assembly was held, in-hauled, and payed out by the winch with no evidence of adverse mechani- cal effects on the winch or the cable, fairing, and clips, while cable tension was within winch capacity; when excess- ive tension was placed on the winch, slippage of the cable relative to the track and fairing occurred (Figure II-10). The winch exerted a maximum pull of 10,000 pounds under stalled conditions, and sustained that load for all loading- cylinder air pressures down to 90 psig. As the winch was stalled, slippage was evidenced by creeping of the tracks, which carried along the unanchored fairing. The towed-system elements exhibited stability for all conditions of the test. The system towed with a very slight "kite" to starboard. It maintained depth during turns; when entering a turn, the tow cable assumed a slight angle to the inside of the turn, returned to a straight course during the steady part of the turn, and veered slightly to the opposite side when the turn was checked, thereafter returning to its straight-course position. II.12 With a cable scope of 700 feet and a speed of 6 knots, the indicated depth was 660 to 665 feet; the line tensions averaged 3500 to 4000 pounds, with occasional surges to 9000 pounds. The angle between the axis of the cable and the water surface was approximately 61 degrees. At a speed of 8 knots, the observed tensions were between 5500 and 6000 pounds, with occasional surges to as much as 9000, 10,000, and 11,000 pounds. One surge to 13,000 pounds was observed. The depressor was damaged when launched in rough weather. The cable fairing, clips, and clamps suffered no damage during towing or passage through the winch, although a number of clips were torn loose and deformed by "hangeups" in passage through the roller and trough system. As a result, some clips failed to swivel freely on the cable and had to be manually aligned. 1365 48) a. View Showing Module and Handling Bale b. View Showing Module Fairing, Bent Starboard Vertical-Tip Plate, and Additions to Stabilizers Depressor as Tested at Sea Figure II-1l II.14 i f nt ‘ - = na? j i." \ a a bik 0b, aa au) a) | Uy oo 7 ‘I : ‘i; \ f 4 ; then spriwhet eLuvert mereay. Uper: oy eporsibbA PAS / s8% 316 hotevt. ss r3ssended EE exert) ree a ' 7 i re ah re a it | View of "Cable Hauler" Showing Dummy Module Gripped Between Treads and Method of Loading the Tracks Figure II-2 II.15 i I al 7 i ‘ . \ i i a 4 by eh ( 2 \ \ ’ { ¥ Was uy " ft ' 7 A ; ays ye, Ss ~ ; ; on: ret uony on MAR estoy Ce a. View showing vertical and horizontal rollers. The fairing is normally posi- tioned with the trailing edge facing outward. «<—b. View showing normal posi- tion of the fairing in relation to the guide rollers. Fairing Guide Roller Installation Figure II-3 EL .1L6 tp Ge ~— ———--+—--- ——o ae —_ Cable Reel Used for Storage of Faired Cable During Sea Trials Figure II-4 AbaE al 7/ Sheave Used for Handling Faired Cable Over the Stern Figure II-5 beat ove Forward Guide Rollers and Transfer Sheave as Seen from Port Figure II-6 Arrangement for Transferring Fairing from Forward Guide Rollers to Trough as Seen Looking Forward Figure II-7 peel) gv pede roan aac Sra ated ito A aly paewaot aN Phot | aera p22 way ls aids ne "aang? © wi0% 7 | im awe" cf pnidoot { View Looking Aft Showing Forward Transfer Roller Figure II-8 ",.-e-and Thence into the Cable Well" Figure II-9 hs 20 ae a ‘paiteot we | nee 0] i) mh wv ry 4 i ' ie Results of Cable Slip Figure II-10 eo oe et APPENDIX II ADDITIONAL PERFORMANCE CONSIDERATIONS R hi yh ie APPENDIX III ADDITIONAL PERFORMANCE CONSIDERATIONS PREVIOUS ANALYSES In order to perform the analysis prerequisite to the design of the cable-towed oceanographic instrumentation system, it was necessary to make specific assumptions re- garding the nature of the hydrodynamic loads imposed on the faired cable and to estimate the value of the resistance coefficient. In the analysis reported in (1), it was recognized that the expression for the dependence of the hydrodynamic loads on the cable angle, as given by Whicker (4), is probably more nearly correct than that given by Eames (5). Eames‘ formulation was selected for this appli- cation, however, since its use results in a conservative estimate of the geometry of the cable catenary and over- statement of the tension. A value of 0.2 was selected for the resistance coefficient on the basis of the best experi- mental data available at that time. On the basis of the foregoing, and the simplifying assumption that the cable angle at the depressor, with respect to the horizontal, would be nearly 90 degrees, the results of the preliminary design study indicated that with a depressor downforce of 4,450 pounds and a length of 6,200 feet of faired cable, a maximum depth of 5,000 feet could be obtained at a towing speed of 7% knots. ELT. 2 “ombsiont nt te ie ; aw! a a bth eh trol Ma xa rink tut rhb Na a wit ‘adh arn dati ae hits We srg fat al f fot nee: say a mylcay niyoshlin a, rh Wy: on se | ee ga Lok Lain eats wi Sot rier: 70 bai Ty" yee ee oe wy. Boi vi al? ie eh et a hae . * : IAM 7 mre bss Abid ie ie ia Kea QL 4? 45 (ti gia an a a O88) yh | eiacata oe ac Diao p nee he 1 ay ee bunch bed ey vi ae ft 90,5 oeege geen aiden ADDITIONAL CONSIDERATIONS Since completion of the preliminary design, further information concerning the hydrodynamic resistance of faired cables has come to hand. Results of recent tests on faired cable (7) show that the minimum value of the resis- tance coefficient to tbe expected for TF-84 fairing is closer to 0.3 than 0.2 in the Reynolds' number range charac- teristic of the present system. In light of this information, a study was made of the effects of resistance coefficient and cable-loading assump- tions on the performance of the system. A digital computer solution based on Whicker's loading assumptions, with a resistance coefficient of 0.3 and using computed values for the cable angle at the depressor (84 degrees at the 74-knot speed) was provided by the David Taylor Model Basin. Calcu- lations based on Eames’ assumptions, using computed values for the cable angles and resistance coefficients of 0.2 and 0.3, were also made. Results are tabulated below for a towing speed of 74 knots, and are shown as a function of speed on Figure III-1. The results at 7% knots given in (2); based on Eames' method, a resistance coefficient of 0.2, and a cable angle at the depressor of 90 degrees, are included in the table for comparison. IIr.3 my aN i i ha mt aba Lp hab lie » ON PR GEN ARR it oP ett ga foe we SCP peer . ANTE Rada WY RUMMY We ven y, ar] ah ‘ wh) i Ay J den | he a, } Wy ” y x Ny tat i} Wa Pe et ee BUtAy>) bay RS a Lind c bby ei AY Bria Lo He ea ; eA f ij mM ») y be aN) Y Bey fi ge Tn hy ae mea et ts Bee HP { = oe bothers Ce 3 if ree BOSE SERS SS PS Re velocity OF \ Ww oO cr 2 t i wom SPs By | idee 8 oo Es i } it t pear eS H 4 i oN © tv i wm Q 5 re) iy. | arse } | ! f L | : | : ao Hoa iges areas poe | Ai | Cait 0-3 Go 012 | | iH eeu a et Apert Up ls RO Esdba §Sses sea ren a eed { | | BL FES HN 7/1000 1 he ace, ~ pe/1000 at ‘surf bebe bchaah ] ! _ | Cable Sco nsion e ibwibbinned blvd dens CRE Re Rane De peaes fests Sy ca cee een eae a lacie ee ee ee Whicker' Bo Leadings skeet sae ele bres orks (eeee bere Pnpet ot ieee ang. = 0.3 ee ed pean sea Pe TENSION oS R Be ae ciel pees Ke, = “Resistance ae ar Baas ae treet erect ee feideltele cela | Bae me ae an ait tore sal q Ldenhbans: ee icslernumorae teh, EL tala De a aa Pe doh Riss: hala Ci <1 = abet wh } f eee heal Y i nants | i ; ‘ 5 fi 5 ae # ee ays ae ; mer t Th , O AU ay : wren ay a aurewete ie 4a ria » iP BLE! (hist iets he fee whitey 4) ‘ Lyre teas eA ihe bea Cable Loading Assumption Eames Eames Eames Whicker Resistance Coefficient OR2 OF Ons (0)63) ° Cable Angle at Depressor 84° at 74%-knot tow speed 90 Scope of Cable Required to ty 1 t 1 A@tatin A pasta 6 5000 ae OvPU See Bye By delt Tension at the Surface 15,000 15,400 26,000 15,000 lbs lbs lbs lbs The results indicate that if Whicker's loading assumptions are correct, the desired performance can be attained, even with a resistance coefficient as high as 0.3, without exceeding the arbitrarily imposed limitation of 15,000 pounds on cable tension. Computations for Sea Trials It was determined from tow tests that at the higher values of towing speed the depressor imposes an angle of 81 degrees onthe lower end of the cable. Since this value is slightly less than the 84 degrees predicted in (2), and since an 0.782-inch-diameter cable was to be used for the sea trials in place of the 0.75-inch-diameter cable on which previous performance predictions were based, estimates of the cable geometry for these new conditions were required for comparison with sea-trial data. These computations were made on the basis of Eames' formulation, using a resis- tance coefficient of 0.3; the results are shown in Figures III-2 and III-3. IImr.5 7 i : a iy Pan KA De i. " ee Ties : j Cen ay i a ry Ln v aa, #8 ; ae Ll ‘ { T OF , Mi i f ea Nee By OR ee. Gea a tidy if : ae. O00 ake RD tie ry ‘ ; » yy i pe. ve ment! wet een ") a sah ; ae ina ABA wet rats aes saurid tng ie ne : i} i! Py aR Vin | soit hit Pes aN ae seas ; rs peal, Bos mina bd Ai “en ie ind ff Ly an tut Spi 9: te: ine ae | | | ‘ie bali ne! nei Nady rite, Labanah ms | repay: ah ‘Beg aie dae ca ae ba ss i 2 matin te ahold, hadbiiag bo tan A an 6H neta roa € Nea hangs _* be shy own ney "Miva vies ‘hi: dagen Ae ue Fs x vase Nes ti ee shai Ft bike ua is! de A ey af a 4 , , yey ube Fe AE eT Oy pre! ; . > ha a me ke Coie ee a heh ens ak an ee Go 2) sa y ; r ‘ i a b> ‘ Le lee = 5iekm & Od wees Nag es LD het Ree A na: et OGM. 9 (GAVE watery) ce west Mie, el ae: we Phitele" j » ge rey Poi as rd , 4 7 | | a aN oe oF 26 Fhe Oe me 4 ie) | ’ : f ny » / i A \ 1 7 oS : penntsieed hion 7 SITS ne a wed: Vara RT Tt i ma ae | ito rly | aidan aft 30 yaad edo cee ont AoA FR) the ; HAS Z Mi ; i tee, Pak \ \ clas pana | affS Yarns 2 % pktete vieudeve sy ane galione & od | 7 ls OV te tive ed 4a «Hepes tle eR Huge sity % Noda anieal ey | woniu «1 pn. ii Le el ; wh 9 sd i ty TAG ve A i Whee ia’ P ij h, ; hi Nl gies ny n A) 7 fairing Radius of curvature = 1/c, a. General Configuration b. Section A-A Y Radius of curvature c. Section A-A Idealized “% FIGURE IV-l - Definition Sketches For Derivation of Structural Effects On Fairing Stability Iv.4 Beh) ieditvene 4). q * ss ie = bts SaveEtoC “crf, eapete rete aot aeaksaed | ae ealtiah oO noone Lawedwse Bor ery ABI. ° where E is the elastic modulus of the cord, the moment per unit length of cord necessary to maintain the cord in equilibrium in the displaced position, is AL = By C.c y OA : But (Cs (ley T+yc, ; hence 2 ‘it 2 A= EC, Y Tye JA 6 Lae the total moment per unit length due to bending, is then simply the summation of the moments due to all such elementary cords, and is given by es 2 tec, 1 f poe a fo) Since YC, << 1 for most practical problems, we may write a a2 L, = IEC. ¥ ; fa) where I is simply the second moment of the cross-sectional area of the fairing, referenced to the axis normal to line a-b which intersects the center of the cable. iv. 5 1 ee) es ein vs ad ene RAIDS. He an ns ean Rem mR em ce ficieisrunes aau-ne lt He, rimioni rib a thin aly ‘iid made a Loser ahym anit oct” eam al eee huis Ay wos w Cuan aud te hea we), ‘ha TREAD Oe wiht aie if a 7 | on a TENSTON L the moment per unit length due to an externally rT? imposed load, T,, may be found by integrating [1] over the total area of the fairing, assuming 4 to be a small angle and yCy << 1. y, in this case, is just the distance from the center of the cable to the line of action of the external load, and is written y. Dropping the subscript e, we obtain ERReay ay : (3] Iv.6 oh Bias Z y Fh wry wwpanh edo is wit dane wh! Yoene ‘aha’ A ea as aS Meliod Mak 29. och ‘a, at whi zs \ a fi a 4? ebmalituy ie ators i ima « wb i? i nay So NEaT! Fi 0 ; asl , om ‘ere “ye fe b Ree a APPENDIX V REFERENCES 4 if ’ “dn aida A Wi tial iy aR an (1) (2) (3) (4) (5) (6) (7) REF ERENCES Ellsworth, Wm. M.: General Design Criteria for Cable- Towed Body Systems Using melee and Unfaired Cable; Systems Engineering Division, PneumoDynamics Corporation, Report No. TN-SEDU-6634-1, October 1960 Ellsworth, Wm. M. and Gay, S.M.: Preliminary Desi of a Cable-Towed Oceanographic Instrumentation System; Systems Engineering Division, PneumoDynamics Corporation, Report No. TN-SEDU-6634-2, February 1961 Bonde, L.W.: Investigation of a Tractor-Type Winchin Machine for Handling Faired Cables ae In-Line Instrument Modules; Systems Engineering Division, PneumoDynamics Corporation, Report No. TN-SEDU-6634-3, July 1962 Whicker, L.F.: The Oscillatory Motion of Cable Towed Bodies; Doctoral Dissertation; University of California, 1957. Eames, M.C.: The Configuration of a Cable Towing a Heavy Submerged Body from a Surface Vessel; Naval Research Establishment (Canada) Report PHx-103, November 1956. David Taylor Model Basin letter 9250/7100/(549:JT:1m) to PneumoDynamics Corporation, dated 21 May, 1962 Gibbons, Thomas: Hydrod ic Characteristics of a Systematic Series of oti Cable Fairings; David Taylor Model Basin unpublished manuscript. DISTRIBUTION LIST ae arene Reporis Generated by Systems Engineering Division, Pheumopynam.cs Corporation under Office of Waval Research Contract Nonr 3201 (00) bo pe Office of Naval Research L Washington 25, D. C. Attn: Biology Branch (Code 446) Surface Branch (Code 463) Undersea Warfare (Code 466) Special Projects (Code 418) Acoustics Branch (Code 411) Finid Dynamics (Code 438) L Contract Administrator Southeastern Area Office of Naval Research 21LL0 G Street, N. W. Washington 7, DB. C. Director Naval Research Laboratory i Attn: Technical Services Information Officer Washington 25, Db. C.- a U.S. Navy Hydrographic Office Attn: Division of Cceanography Wasnington 25, DB. C. ad Chief, Bureau of Ships Navy Department Washington 25, BD. C. Attn: Code 671D Attn: Code 34ic 1 Attn: Code 688: “ attn: Code 370 Chief, Bureau of Naval Weapons Reavy Department Washington 25, DBD. C. N jen Attn: FAME-3 Rupe 252 Commanding Officer & Director a “U.S. Navy Electronics Laboratory Gan Diego 52, Californie Attn: Cede 2250 commanding Officer & Director U.S, Naval Civil Engineer~ ing Laboratory Port Hueneme, California Attn; Code L54 Commander Navel Ordnance Laboratory White Oak, Silver Spring, Maryland Attn: E. Liberman, Library — commanding Orsicer Naval Ordnance Test Station Ching Lake, California Bttsm: Code 753 Code 508 commanding Officer Nawal Raéiological Detense Laboratory San Prancisco, California Commanding GfEicer & Pirecese Pavid Yaylor Model Bagin- Washington 7, DB. C. Commanding Gffiicer u. S. Naval Underwater Sound Laboratery New London, Connecticut U.S. Havy Mine Defense Laboratory Panama City, Florica Attn: Commanding Cfficer Commanding Officer U.S. Navy Air Development Center Jchnsville, Pennsylvania Atta: NADC Library ; | < Fhe wet a At) a a tl pe tf ur YP Hawi nny ue bw te whan taal bam | 7 ae Phi, tpi ie stored) a aa pag pysn ; | ig Se okie h, Vy aired le, he a A LA t peel Roe ar wy ry TENS & Bro1) 0 pen aipaes isaac a ee te . sgh SM a, ee ie ee (aah soy) ci cf es UES Bae | thine gh ‘cited wa RPT Ayia, dan’ Lath fae | BRA 4) a a wee ro yess’ y.! AIR matey Si | re iy: Ay 24 tT nek Ht eae ery cry ube AWE yl Tes am B. frs id 7 oO Ay ote tre * ae Sa sicele: | ean ews rT te tan A | Bae 1% MPLA con RM MOB i 1 ee ib cah (a9 agai LE ho ae i | a pias a pid Ab) AUNT lain nies egal eae : ciel aaa aie > ea i eg i itu Lig Paid Diese | 0 ae me, ee ‘ Pe Lia salu, een gi) Lear . ee: ms will : leh Sag WR ee a ae Galle ee SE EAA if (f Vinee any ' cy eat ae MA aE nigel BP Oey aaa a Tos : Pa hid Gi h, tha Wena. i ie et i er ee ery ae 7 BAA Adc t eA, AU Na att | a, eT ae Bh ant eee bk eee hte aN MOWAGA CLE, AG 4 ee ayy, na Sh ial aa via os 9 aad re Ge £4 A Wes ET TG: rece.” ho ae a ae ake) ee ae Witte Laie Brite obs ey). oe 29 OC eae etdosay,. Te SOE peda Porites RAT MM SRL T BONN as diye She ace nk) ost. RP Geta Hien! eR, . - DAEs CL “an SHOT SoH view, eB i aaculi aniyol? 7 eee Te} wok 2970 Dail ta (8 = Mess eee BH! (ape reeys3 SRO AS bts eed eee) Lane Vie, weil, Wai? ~ t= i 7 7 ee Sep Bre 8: Be) { Piz) & , a Ley -" A - : Ms a YS ee, nit ie ps2 testo tToD » 4 , j eb ig ark r ne a eles St ae com 5 ok oa ‘ ; 4 Af tO mooie Lea) WACKY + ry : ete i GAL a) Route) =e wine ae ee CTA : i, My ad Didnt 40) gf a Ins Bak Ws ' ‘ ; iN : ‘ } : : : rs no htahaund keane aki! x 5 ; x, dua é 1] ry ae = Baws i te 1 [ As . . os . / ; | we pnts | oh ; Deka | ' Bal isentoee os i leu'ett AF -s “ r et . } : 2 ets oe Oey Ay ‘jdt ate 7) ua Nas ad Can. 1h 4 a e am. ie ‘ Pigetee whrIonl $A weet aicrad . } nee i RONAN OeRe NSO finaeS yes ; oy w Inve aH at? Py . Row? &! ily OmmMiainae Sh tae LP = sige hy i , ) ae ; = \ 7 tat RANG bs ira os tre LAY is ay ~ Pp se OSie, 2 , : } Pt 2am f Uy, mike a 5 ls hey j 2S } betes east a ‘ Ls ‘j 7 | 4 ; a at i Le a a WA ete? shat iy “ bbb \* y ‘ a | ‘ tcl yy jay fa) ‘ (paeeanllnd ris ra ; 4 » ‘ i. - d . i) t 1 ed f A a ol LO Headquarters, 0.5. Air Force Washington 25, D. . Attn: APDRT-RD (Lt.Col. damison) Commander Headquarters, Detachment 2 Air Force Research Division Geophysical Research Directorate Laurence G. Hanscom Field Bedford, Massachusetts Army Research Office Office of the Chief of R&D Department of the Army Washington 25, D. C. Attn; Research Support Division U.S. Army Beach Erosion Board 5201 Little Palls Road, N. W. Washington 25, D. C. Office of Technicai Services Department o£ Commerce Washincton 25, B. C. ASTIA, Document Section Arlington Hall Station Arlington 12, D. C. Commandant (OFU) UD. S. Coast Guard Washington 25, D. ¢. U.S. Naval Postgraduate School Monterey, California National Research Council 210L Constitution Avenue Washington 25, D. C. Attns Committee on Undersea Warfare Attn: Committee on Oceanography Director @.S. Coast & Geodetic survey Department cf Commerce Washington 25, D. C. Attns Division of Tides & Currents Director of Metecrological Research U.S. Weather Bureau Washington 25, DBD. Cc. Director Bureau of Commercial Fisheries U.S. Fish & Wildlife Service Washington 25, D. C. Director Woods Hole Oceanographic institution Woods Hole, Massachusetts Director Narragansett Marine Laboratory University of Rhode Island Kingston, Rhode Island Chairman Department of Meteorology and Oceanography New York University New York 53, New York Gulf Coast Research Laboratory Ccean Springs, Mississippi Attn: Librarian Director Lamont Geological Observatory Torrey Cliff Palisades, New York Director Marine Physical Laboratory San Diego 52, California Director Hudson Laboratories 145 Palisade Street Dobbs Ferry, New York Director Applied Physics Laboratory University of Washington Seattle 5, Washington Bell Telephone Laboratories Whippany, New Jersey Attn: Dr. W. A. Tyrrel ee he | : Leinyotas) 20 pes sla Dre LACE oA egivso® shLTDERe B sal ay 2.0 oD -G 783 nosed teh sede sae Sparen speoREIO Sion wboow eo igus aay aes Lavdseupmt ye Lou Bang ye Tish weit ye. ee i ee MPSA hnatha a We Bs: ans te ye aG, Sugied, sty Sho ses , b neere gis a | ypokorcetns lc deat 18g 9G” | yligesponesag: bie TC’ Yala nd: Ahot wee S) Bey we ER Mier ett yaotpaadas ‘tqgreetagia .epaitge aero 250 gabaerqnde uit coloos, Sec eal igo 9 a WA AEST: OP eget weu wobde an = nee ares yrosarodaal feekevdd ayaa” elmoeki fen St opel sve i ty REE) webcodearw!s. ont dpatiz obre tite Bey Ns oe, OC a9 pall : coset VECJ Greco eliayn’ OFt ing negonidecs 79. \v2taany ales A nes TEsK : .- Te laden Sip 3) wees ee Lf feN) gat wet J ieee HM 22! AoA & hy fle ae A (as ae Patna uae aa $0) SPO Bae ee ‘ ; sf , f AREY LA aes : ¥ mA va i datkepen J2600 BLS: Say. f hpak derail: ata SAS FHOU | ety ne . ae pe ‘eee Rae Pm pats ANE aaieane & ba r yaad) ho). Rae wed: 40, ny, pe ra ies wi tele me eer 4p cone Stantord Research Inetitute Menlo Park, California Department of Geodesy & Geophysics Cambridge University Cambridge, England Lamont Geophysical Observatory Bermuda Field Station St. Georges, Bermuda University of California, La Jolla Marine Physical Laboratory Seripps Inatitution of Oceanography San Diego 52, California Attn: Mrs. Christine Baldwin General Motors Corporation Defense Systems Division General Motors Technical Center Warren, Michigan Attn: Mrs. Florence Armstrong, Librarian Mr. L. L. Higgins 6433 Fallbrook Avenue Canoga Park, California Professor Basil W. Wilson Texas A. & M College College Station, Texas Mr. BE. J. OkLeshen Section Chief Advanced Development Engineering The Magnavox Company Fort Wayne 4, Indiana ‘The Perkin-Elmer Corporation 5670 Bast Washington Blvd. Los Angeles 22, California Attn: Mr. George Artiano Entwistle Manufacturing Company 1475 Elmwood Avenue Providence 7, Rhode Island Attn: Mr. 0. Minardi U.S.N. Underwater Sound Laboratory New London, Connecticut Attn: Mr. Seymour Gross a p= NORTVRONICS, Maxine Equipment Department 77 "A" Street Needham Heights 94, Mass. ATTS: Mrs. MacWilliam Pechnicail Librarian Lt. Cmdx. BE. W. Sapp Y.S.S. Maloy {DE 791A) c/o PPO New York, New York Bureau of Ships Department of the Navy Washington 25, DB. C. Attn: Code 440 Code 420 Code 447 Code 526 Code 632 Product Design Engineering Department General Electric Company Building #1, Room 119 Farrell Road Plant Court Street Syracuse, New York Attns Mr. 0. H. Harse LCdr Thomas Sherman Office of Naval Research Department of the Navy Washington 25, DB. C. American Steel & Wire Co. 1625 K Street, N. W. Washington 6, D. C. Attn: Mr. Phil Wright (Mx. Perris) (Cdr. Aroner} eo) ue wae MY aay ree Sy are Me toanodigt fave low Ue7d PRE 0." 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