TN ~-J¥EG

Technical Note N- 1446

THE CEL 100K PROPELLANT ANCHOR — UTILIZATION FOR TANKER MOORINGS IN
SOFT CORAL AT DIEGO GARCIA

By

DaGeeioue and! R. J. Taylor A HOTS
DOCUMENT |

July 1976 COLLECTION 7

Sponsored by

OCEAN ENGINEERING AND CONSTRUCTION PROJECT OFFICE
Chesapeake Division
Naval Facilities Engineering Command

Approved for public release; distribution unlimited.

CIVIL ENGINEERING LABORATORY
Naval Construction Battalion Center
Port Hueneme, California 93043

ME OMHeS DYE 4.

em pr a et a og 9 Saeeenlr| ER —eye Aeome

\sarthee Le

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REPORT DOCUMENTATION PAGE | BEFORE COMPLETING FORM

T. REPORT NUMBER 2. GOVT ACCESSION NO| 3. RECIPIENT'S CATALOG NUMBER
TN-1446 DN587091

5. TYPE OF REPORT & PERIOD COVERED

4. TITLE (and Subtitle)

THE CEL 100K PROPELLANT ANCHOR — Final; Oct 1974 - Sep 1975
UTILIZATION FOR TANKER MOORINGS IN SOFT
CORAL AT DIEGO GARCIA

7. AUTHOR(s) 8

By D. G. True and R. J. Taylor

6. PERFORMING ORG. REPORT NUMBER

CONTRACT OR GRANT NUMBER(s)

| 10. PROGRAM ELEMENT, PROJECT, TASK
AREA & WORK UNIT NUMBERS

9. PERFORMING ORGANIZATION NAME AND ADDRESS

CIVIL ENGINEERING LABORATORY

Naval Construction Battalion Center OPN; 42-020
Port Hueneme, California 93043 |

11. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE
Ocean Engineering and Construction Project Office July 1976

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Chesapeake Division

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SUPPLEMENTARY NOTES

18

19. KEY WORDS (Continue on reverse side if necessary and identify by block number)

Anchors, Embedment Anchors, Propellant Anchors, moorings, tankers, coral.

20. ABSTRACT (Continue on reverse side if necessary and identify by block number)

This report documents the design of the CEL 100K Propellant Anchor, and
outlines the mooring requirements and designs as well as the procedures, equipment, and
operations involved in installing the propellant anchors and connective gear for tanker
moorings at Diego Garcia. This successful installation demonstrated that this type of
anchor can be used to advantage in Navy and other applications, particularly where uplift-
resistance is desired or where effective anchoring is needed in a hard seafloor.

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Library Card

Civil Engineering Laboratory

THE CEL 100K PROPELLANT ANCHOR — UTILIZATION FOR
TANKER MOORINGS IN SOFT CORAL AT DIEGO GARCIA
(Final), by D. G. True and R. J. Taylor

TN-1446 30 p. illus. July 1976 Unclassified

1. Anchors 2. Embedment anchors 3, Propellant anchors I, 42-020

This report documents the design of the CEL 100K Propellant Anchor, and outlines the
mooring requirements and designs as well as the procedures, equipment, and operations involved
in installing the propellant anchors and connective gear for tanker moorings at Diego Garcia.
This successful installation demonstrated that this type of anchor can be used to advantage in
Navy and other applications, particularly where uplift-resistance is desired or where effective
anchoring is needed in a hard seafloor.

Unclassified
SECURITY CLASSIFICATION OF THIS PAGE/fWhen Data Entered)

CONTENTS

INTRODUCTION... .
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initiating Aggenijlh? 6 6 0000000000060 0 0
Projectile Assembly ....-+++-+-++-. -
ILS 6 G Mo so 0 oO 0 80)-0 0 OO G o 6 6G 6 oO 6
MOORING IDBSIGN 6 6 6 6 ovo 0 Go OG OOOH OOo OO
INSTALLATION EQUIPMENT AND PROCEDURES. . ..... +. «@

INSTALLATION OPERATIONS SUMMARY. . . © »- © © © +» «© © «© © «
FINDINGS ........ .-

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Qmerninlems5 6 0000000000000 000 500 40
CONGHUSIONS. oo 000006660606 6 6 5 O60
RBDERNGIS 56 6 6 6060600060 0650 500006 66
APPENDIX — Anchor Installation Log .......

LIST OF ILLUSTRATIONS

Figure 1. The CEL 100K Propellant Anchor System being
deployed, loaded with a coral/sand fluke and

@ TeQleIcHENllle PHSEOMs o 6 56 6 boo oO 6 OO
Figure 2. Safe-and-arm device ........ 0 0
Figure 3. Projectile assembly in gun barrel et anelnee

llogiel disine aieaeinecls 6 515.50 660656000500
Figure 4. Retrievable piston after use... . 5 0
Figure 5. Rear of fluke, showing base plate ane oles

Oc SNE PHM 560 6 00000 6 5 6

Figure 6. Propellant anchor mooring leg Sonera ey out .
Figure 7. Mooring leg configuration at temporary site .
Figure 8. Typical mooring leg See at
permanent site. ..... .- sation decd awe To. 1%
Figure 9. Deployment of anchor system, Silewed from crane
barge looking toward winch barge, with mooring
buoy (left foreground) secured to crane barge .
Figure 10. Installation sequence of CEL 100K Propellant
IMCINOIC 5 56 0600600000000 6006 00

LIST OF TABLES

Table 1. CEL 100K Propellant Anchor Data for the Diego
Garcia Permanent and Temporary POL Moorings.

11
13

18

18

17

Eyre
ie

ate

INTRODUCTION

Reliable long-term moorings over semiconsolidated-to-hard rock
seafloors require specialized anchors. Conventional drag-burial anchors
are not capable of penetrating consolidated seafloors; the snagging of
flukes on outcrops without full penetration cannot be relied upon to
provide a durable mooring. Drilled-in anchor piles are commonly used
and have proven reliability. The cost of installing drilled-in piles is
reasonable when the mooring is situated near a large center of industry
where emplacement equipment is available. This cost becomes excessive
for a mooring at a remote location.

Two remotely located moorings over a soft coral seafloor were
required at the U. S. Naval Communication Station, Diego Garcia (a
British territory in the Indian Ocean) for petroleum-oil-lubricant (POL)
offloading. One was designated the ‘‘temporary’’ POL mooring, and the
other was designated the ‘‘permanent’’ POL mooring. These designations
do not necessarily imply the expected use of each mooring because the
temporary mooring will probably be used as long as it is functional.

The temporary facility, originally completed in 1971, had been scheduled
to be replaced eventually by the permanent facility.

The temporary mooring consisted of conventional drag-burial anchors
and concrete clumps connected to mooring buoys. This mooring had been
dragged on several occasions during high winds, resulting in breakage of
fuel pumping lines on three separate occasions, fortunately without
vessel grounding or damage.

In 1971, the permanent POL mooring was in the design stage; the
selected design consisted of large STATO (drag-burial) anchors, weight
clumps, and long lengths of 2-1/2-inch (64 mm) A-link chain. Large
propellant anchors were suggested to stabilize the temporary mooring.
Shortly thereafter, the design of the permanent mooring was re-evaluated
because of its potential susceptibility for similar dragging.

As a result, the CEL* 100K Propellant Anchor System was selected to
secure both tanker moorings at Diego Garcia because of the system’s
adequate capacity, minimal requirements for peripheral hardware, economy
of installation at remote sites, compatibility with onsite installation
workboats and equipment, and timely availability. This report documents
the design of the CEL 100K Propellant Anchor; outlines the mooring
requirements; describes the installation procedures, the mooring designs,
and the equipment used to install the moorings; and provides a summary
of each anchor installation.

Civil Engineering Laboratory.

This work was sponsored by the Ocean Engineering and Construction
Project Office, Chesapeake Division, Naval Facilities Engineering Command,
as an augmentation of facility construction under the cognizance of the
Pacific Division (PACDIV). Underwater Construction Team One (UCT-One)
was responsible for installing the moorings. CEL provided technical
representatives to furnish propellant anchor mooring design information
to PACDIV, to participate onsite in the mooring installation, and to
supervise the operation of the propellant anchor.

ANCHOR SYSTEM

The CEL 100K Propellant Anchor was developed for the Navy’s Supervi-
sor of Diving and Salvage to provide salvage anchoring capability at
sites where the seafloor was not suitable for drag-burial anchors. In
addition, it was desired that it be capable of operating in unconsolidated
sediments so that a single system could be carried aboard a salvage
vessel (ARS, ATF, or ATS) for use at any site. The initial version of
the system was developed by Aerojet-General under contract to CEL between
1966 and 1968, as documented by Thomason, et al. (1968) and Naval Ships
Systems Command (1970). Subsequently, the system was modified to reduce
fabrication costs and to improve firing system safety, as described by
Smith (1971). Based upon tests of the modified system, the launch vehicle
base was strengthened, and anchor projectiles were modified to function
similarly to those proven in tests of the smaller CEL 20K Propellant
Anchor reported by Taylor (1976).

The anchor system (Figure 1) consists of a launch vehicle, a safe-
and-arm (S/A) firing device, a propellant cartridge, a projectile assembly,
and lines.

Launch Vehicle

The launch vehicle consists of a gun mounted atop a quadrapod frame
with a square base. It measures about 8 feet (2.4 m) by 8 feet (2.4 m)
by 12 feet (3.7 m) high and weighs about 12,000 pounds bare. The gun
barrel is a steel forging having the following dimensions:

Dimensions, in. (mm)

Inside diameter 10 (254)
Outside diameter 17 (432)

Overall length 42 (1,067)
Internal travel 36 (915)

Breech diameter

(internal upset) 6 (152)

It is designed to operate with a peak pressure of 35 ksi. A breech

block is fitted to the breech and screwed in over the propellant cartridge
to contain the propellant gases during firing. The outside of the gun
barrel is fitted with four double padeyes for pin connection to the
quadrapod legs. These legs are bolted to the ends of four beam sections

2

_ ee 2 ~~
The CEL 100K Propellant Anchor System
being deployed, loaded with a coral/
sand fluke and a retrievable piston.

Figure 1.

that form a square base. The beams support the vehicle and serve as

drag surfaces to limit recoil. They must withstand a distributed reaction
during firing, peaking at about 2 million pounds (9 MN). Diagonal

bracing is attached across the corners of the base providing the strength
required to sustain the large outward loading produced by the propellant
gases that escape the gun barrel shortly after firing. A circular drag
plate is attached to the gun barrel atop the leg eyes. Tie rods are
fitted to this plate to secure the projectile assembly before firing.

Firing Assembly

Included in the firing assembly are a reusable S/A device and the
propellant cartridge.

The S/A device effectively makes the system safe while on deck,
arms at a preselected depth, and then causes the system to fire. This
device, shown in Figure 2, is screwed into the top of the breech block
and contains a firing pin that is driven downward to detonate the propel-
lant charge. An electric current, which must be at least 0.3 ampere at
24 volts, actuates solenoid valves, releasing gas pressure. The gas

3

ai

Meg oS

refillable : 7

cannister a 4
, ee.
yap ey

; )

x i
Re

AS
zt

S&A base

Figure 2. Safe-and-arm device.

valving
assembly

breaks a 400-psi (2,800 kPa) shear
disk and drives the firing pin down-
ward with an energy in excess of 500
inch-ounces (3.5J).* A safety lock-
out plunger prevents firing pin motion
unless the plunger is moved in line by
a preselected level of hydrostatic
pressure. Normally, a separate elec-
trical line is extended to the sea
surface to provide actuation, although
an on-vehicle battery pack coupled to
a touchdown or acoustic trigger could
be employed.

The propellant cartridge consists
of a cartridge base, capable of con-
taining the gun barrel pressure, a
plastic tube and foam plastic plug to
contain the charge, and a standard
M-58 primer. Firing occurs when the
firing pin in the S/A device strikes
the percussion cap at the rear (top)
of the primer. A peak force of about
2.8 million pounds (12 MN) is generated
during firing to act downward on the
projectile assembly and simultaneously
upward on the launch vehicle.

Projectile Assembly

The projectile assembly (Figure 3)
includes the piston, shown separately
in Figure 4 and the anchor projectile,
or ‘‘fluke.’®’? The dimensions of the
flukes are given below:

* M-58 primer detonation requires
between 60 and 160 inch-ounces
(0.4 to 1.1J).

Value for

Dimension Coral/Sand Fluke Sand/Clay Fluke
Length, ft (m) 555 GloGS) oJ (oO)
Width, ft (m) DoT) (Ms 3) 3633 (oO)
Thickness, in. (mm) i @S5) ili@25))
Weight, 1b (kg) 900 (408) 1,250 (567)
dnea, BS Que) 12.5 (1.15) 21.5 (1.99)

The dimensions of the piston are given below:

Dimension

Length, in. (mm)

Outside diameter, in. (mm)
Inside diameter, in. (mm)
Hollow length, in. (mm)
Weight, 1b (kg)

Value for Piston

34.5 (876
10 (254)

of (Zz)
25.4 (638)
700 (320)

The piston is hollow, to accomodate the cartridge; the lower end is
fitted with an eye for connection to the piston retrieval line and
retainers to maintain proper alignment during firing. It bears against
the rear of the projectile, shown in Figure 5, with a peak force during

firing of about 2 million pounds (9 MN).

The projectile fits below and is driven by the piston. It may be
designed for hard coral or other rock, soft coral, dense sand, or
softer unconsolidated sediments. For all but the hardest rock, projectiles
are constructed from 1-inch-thick (25 mm) high-strength steel plate.
The basic design is a flat anchor plate with a backbone plate to provide
strength during installation and service and an eccentric point of
attachment to force keying (rotation toward the horizontal). For hard
rock, a design similar to that proven effective with the CEL 20K Propellant
Anchor in basalt would be used. The projectile assembly is secured in

the launch vehicle by tie rods. The lower
attached by shear pins through small holes
backbone plates, and the upper ends extend
dragplate and are secured by nuts atop the

Lines

ends of these tie rods are

in the rear of the anchor and
through holes in the barrel
drag plate.

Lines are connected to the projectile and piston and are faked in
figure-8 loops around timber pads on the bottom of the launch vehicle to
allow rapid payout as the projectile assembly is launched downward. The

Figure 3. Projectile assembly in gun barrel with anchor load line
attached.

main anchor load line is faked on the side of the launch vehicle base
adjacent to the eye in the projectile, secured to the acceleration-
activated release mechanism on the side of the base, and extended outward
toward the intended direction of major loading (if loading will have a
lateral as well as an upward component). The piston retrieval line is
faked on the opposite side of the launch vehicle base and may be lightly
secured to the launch vehicle or extended to the sea surface. The
lengths of these lines may be adjusted to fit the water depth, the
mooring design, and the connections to be completed after firing by
divers or by remote mating devices, The characteristics of these lines
as used at Diego Garcia are given below.

Line Value for
Characteristic Anchor Load Line Piston Retreival Line
Material Improved Plow Extra Improved Steel
Steel
Coating Galvanized None
Construction 6 x 37 Right 6 x 25 Right Regular
Regular Lay Lay With Independent
With Indepen- Wire Rope Core
dent Wire Rope
Core
Diameter, in. (mm) Io75 (44) 1100) 1@25))
Breaking Strength, 1b 230,000 (1020) 108,000 (480)

(KN)

Figure 4. Retrievable piston after use.

Figure 5. Rear of fluke, showing base plate and holes for shear pins.

MOORING DESIGN

Moorings were required on an intermittent to frequent basis for the
offloading of POL from tankers. The permanent moor was designated for
use by tankers up to and including the AOE-1 SACRAMENTO Class 53,600
dead weight tons displacing (dwt) (54,500 metric tons), whereas the
temporary moor was limited to the AO-143 T5 Class, displacing 38,000 dwt
(38,600 metric tons). A four-point spread mooring was required at each
site in order that ships would remain relatively stationary while offload-
ing fuel into installed submarine pipelines. The moorings were required
to be maintained in winds up to 27 knots (14 m/s) with gusts up to 36
knots (19 m/s) and with currents up to 0.5 knot (0.26 m/s) from any
direction. In this environment, the maximum forces imposed on a mooring
buoy by the vessel in a four-point spread mooring were determined by
Fluor Corporation (1973) to be 152,000 pounds (680 kN) for the AOE-1 and
115,000 pounds (510 kN) for the AO-143.

It was required that these moorings be anchored at sites having
variable coraline seafloors. Site conditions were reported by opera-
tional personnel and confirmed by diver reconnaissance to be coral heads
and coral overlain by a loose gravel/sand/silt sediment at the permanent
site, and bare coral at the temporary site. The installed conventional
drag-burial anchors at the temporary site were not embedded and were
visible on the seafloor surface, showing signs of having been dragged
without becoming buried. Standard penetration tests conducted in the

8

area of the permanent site to elevations of about 50 feet (15 m) below
sea level indicated very weak cover, this material was removed subse-
quently by dredging. Diver-operated water-jetted probes revealed 1/2
(.15 m)to 5 feet (1.5 m) of loose cover at most anchor locations at the
permanent site after dredging. No data were obtained prior to anchor
installation to indicate the strength of the underlying coral at either
site. Consequently, anchor projectiles were prepared in two sizes, the
smaller for medium-strength coral and the larger for soft and broken
coral to provide flexibility in onsite anchor selection to obtain the
desired performance.

Experience has shown that propellant anchors are more efficient in
harder materials, as indicated by Mayo (1973), Smith (1971) and Taylor
(1976). Accordingly, the capacity of the larger projectile in an assumed
softest credible material was taken as a lower limit to design capacity.
Based upon a buoyant density, measured on grab samples of 51 pcef (0.82
em/cm>) and an assumed friction angle of 30 degrees, this minimum capacity
was calculated at 148,000 pounds (660 kN) by the method of Taylor and Lee
(1972).

Four-point spread moorings were required to fit the operational
needs for POL offloading at Diego Garcia. In order to provide redundancy
and an acceptable factor of safety, a leg configuration employing two
anchors and a load equalizer was selected. A chain-load equalizer was
selected to make use of the ample chain available onsite. Also, the use
of chain precluded the wear and fouling problems that might arise if a
wire rope running over a sheave were used instead. The tensions on the
two ends of the equalizing chain T, and T, and the tension in the buoy

chain qT, are related as ! -

The approximation is good for small angles between the two opposing
portions of the equalizer chain.

Combining to eliminate the smaller chain tension gives

a

7. eS Seea SIND et Be
2 1 + exp(-t)

The factor of safety (F.S.), in terms of known forces, is then

H[1 + exp(-7u)]

at

Wo Bo S EVA. eS
z B

For steel against steel with no galling, the friction coefficient is
0.15, as presented in Carmichael (1950), giving

He See el O24 H/T,
If the anchor holding capacity (H) is assumed to be 148,000 pounds (660

kN) (as conservatively estimated above), the factors of safety for the
mooring legs at the two sites are as follows:

F. S. for
Design load, equalized pair
Site T,> lb (kN) = 1.624 H/T,
Permanent 152,000 (680 1.58
Temporary 115,000 (510) 2.08

These values compare favorably with the a priori required factor of
safety of 1.5, and also were considered highly satisfactory in view of
the high degree of conservatism incorporated into the assumptions of
sediment characteristics made in estimating anchor holding capacity.

The general layout of a propellant anchor mooring leg is shown in
Figure 6. Legs of this configuration were incorporated into mooring
designs, and construction drawings were prepared for the temporary and
permanent sites by PACDIV.

The single two-anchor hookup shown in Figure 7 was used at the
temporary site. At the permanent site, a short length of chain was
added between the buoy and the load equalizer to place the equalizer
below the draft depth of ships using the facility. Also, two 750-pound
(3.3 kN) LWT anchor backlegs were added to retain the buoys in their
desired position when not in use, and a slack backup leg consisting of
two 6,000-pound (27 kN) STATO anchors and three shots of chain was added
to provide emergency protection in the event of failure of one or both
propellant anchors; this configuration is shown in Figure 8. On the
turning point leg at the permanent site, four propellant anchors were
used, with the outer two connected through an equalizer; the LWT and
STATO legs were omitted.

INSTALLATION EQUIPMENT AND PROCEDURES

Included in this section are the vessels, shipboard load-handling
equipment such as cranes and winches, the diver assistance used to
effect installation, and the procedures associated with their use.
Details of procedures and equipment were described more fully in the
Operation Plan presented by Underwater Construction Team-One (1975);
hence, the description given here is intended to summarize and to update
that given previously.

water line

load equalizer and ground ring

turning buoy —,

ENC

240 ft (73 m)—4

180 ft (55 m)

ship's line

5,000 fr (1,500 m)

embedment anchors

shore line

shackle

One 30-ft 2-1/2-in. chain

me load equalizer

SS One 35-ft (11 m) 2-1/2-in. (65 mm) swivel chain
One 45-in. 2-1/2-in, (64 mm) chain

1-3/4 in. (44 mm) wire rope

embedment anchors

Lowa al

Figure 6. Propellant anchor

General Notes

1. Final positions of embedment anchors depend on buoy location.
Positions of buoys as shown are suggested locations only.

2. Additional wire rope will be necessary between buoy and load
equalizer to prevent submergence of buoy if small buoys are used
at the temporary site.

3. Cathodic protection not shown for clarity
4. Make connections in a regular leg as follows

a. use joining link connection between swivel shot and half-shor;

b. connect 1-3/4-inch (44 mm) wire rope open socket directly to ends
of chain;

c, shackle equalizer to 30 feet (9 m) of chain rising to buoy

d. connect riser chain to buoy with joining link.

Use added anchor and connections for a turning leg as follows

2. add third anchor with cable and 35 feet (11 m) swivel shot of chain;
b. add ground ring above equalizer, shackle to equalizer; connect third
anchor chain and riser chain to ground ring by joining links

mooring leg general layout.

11

>

Figure 7. Mooring leg configuration at temporary site.

Figure 8. Typical mooring leg configuration at permanent site.

14

Vessels utilized at Diego Garcia for the reported installation were
two YC barges and an LCM-8 workboat. The barges provided working plat-
forms with ample deck space for equipment and anchor hardware. The use
of two separate barges provided flexibility to allow an anchor to be
installed while a previously installed anchor was being proof-loaded
elsewhere. The workboat provided positioning thrust for either or both
barges as well as transportation for personnel and additional hardware.

On the ‘‘crane barge’? was mounted a 30-ton crawler crane fitted
with a single-line hook and a four-part hook capable of independent
operation. This greatly facilitated tilting of the launch vehicle for
preparation. The crane also was essential in lifting the heavy anchor
components during assembly operations and was used to retrieve pistons
after they had been extracted from the seafloor by the winch barge.

On the ‘‘winch barge’’? were mounted three winches — two smaller
ones with 3/4-inch (19 mm) wire and one larger, double drum winch with
1-inch (25 mm) wire and 5/8-inch (16 mm) wire on its two drums. At the
opposite end of the winch barge was mounted a 30-inch (760 mm) -diameter
roller sheave provided by CEL for proof-loading the anchors without
damaging the anchor load line. The main anchor load line was sufficiently
long [110 feet] (34 m) that diver assistance was not required, although
swimmer assistance was employed frequently to facilitate making connec-
tions. This line was retrieved by hauling in on a preattached tag line.

A beach gear purchase section — a nine-part block and tackle designed
for applying large loads to anchor lines during salvage operations — was
threaded with the 5/8-inch (16 mm) wire from one of the center winch
drums to provide the large required proof-loads. A 10,000-pound (45 kN)
dynamometer was attached to a stationary block and rigged to deflect the
5/8-inch (16 mm) line through an angle having a sine of about 0.25 to
provide load datas this, combined with the nine-to-one mechanical advan-
tage of the beach gear, gave an attenuation factor for the load reading
of about 36. The effects of friction were judged to reduce this factor
to 31.5 +1.5. Hence, the desired 100,000-pound (450 kN) proof-load was
well within the range of the dynamometer. The +5% range of precision
of this system was considered satisfactory.

A welder was required onboard the barge to secure connections to
the anchor projectile after system assembly. Also, onsite modifications
to make anchor components mate properly (tie rods to projectiles) required
the shipboard use of a cutting torch on each projectile. In addition, a
well-stocked toolbox was required for system assembly and adjustment and
preparation of the S/A device before each shot.

Briefly, the anchor installation operation began with preparation
of the system by fitting the launch vehicle with a piston, a projectile,
and lines while it lay on its side. After the launch vehicle was set
upright, a cartridge was loaded, the breech block and the S/A device
secured, and the firing cable and a safety line for disarming taped in
place. The system was deployed by crane to the seafloor at a spot
premarked by a small buoy while control was maintained of a tag line
attached to the end of the main anchor load line to effect proper

i)

orientation. Deployment is shown in Figure 9. The anchor was then
fired, the launch vehicle and the piston were retrieved, and the anchor
proof-loaded to at least 100,000 pounds (450 kN). The installation
sequence is shown in Figure 10. The connection to proof-loading gear
and the subsequent attachment to the chain to complete the mooring
hookup were conducted at or above the sea surface.

In order to recover the piston, divers were required to make a
connection between the piston retrieval line and a traveling block on
the barge’s 1-inch (25 mm) wire. This requirement could have been
avoided by using a longer line to the piston, or by preconnecting the
block or a larger haul-in line to the piston retrieval line before
anchor deployment; however, such an approach would have increased the
complexity of the deployment operation. The piston retrieval operation
was time consuming, even with the ample diver assistance available, and
required the use of two winches, the beach gear, and the crane; hence,
it was operationally expensive.

With this in mind, the piston retrieval operation was omitted from
an early shot, and the satisfactory keying of the fluke and development
of holding capacity were verified, at least for the materials at the
reported site. Pistons also were not recovered on several of the final
installations to save time and to expend the used pistons that were
showing some erosion on their outer surfaces due to blow-by of the
abrasive propellant. When piston recovery was not attempted, diver
assistance was not required.

INSTALLATION OPERATIONS SUMMARY

Within 2 weeks, 18 propellant anchors were installed at Diego
Garcia, 10 for the permanent POL mooring and 8 for the temporary POL
mooring. Two fluke sizes and two types of propellant were used during
the installation. A log of the installation operations is in the Appendix.
Highlights are discussed below.

Listed in Table 1 are some of the data resulting from the 19 firings.
Listed data consist of: installation at either the permanent site or
the temporary site (designated by a ‘‘P’? or ‘‘T’®, respectively), along
with the installation order at each site, the nominal fluke size used,
the charge weight, the propellant type, the peak gun pressure, the
anchor penetration depth, the peak recovery force required to retrieve
the piston, and the approximate peak anchor proof- load. Anchors were
proof-tested to at least 100,000 pounds (450 kN). Most anchors sustained
peak proof- loads between 100,000 (450 kN) and 120,000 pounds (530 kN),
although a few of the anchors sustained higher peaks caused by surge,
with the highest being 165,000 pounds (730 kN). One anchor was proof-
tested statically during calm conditions to 150,000 pounds (670 kN).

16

Table 1. CEL 100K Propellant Anchor Data for the
Diego Garcia Permanent and Temporary
POL Moorings

Peak Peak
Peak Piston Anchor
Propellant Gun Penetration, Recovery Proof
Type Pressure, ft (m) Load, Load,
ksi (MPa) klb klb
(KN) (KN)

Fluke Charge
Size, Weight,
ft (m) Ib (kg)

Installation
Number

Def] 2-5) 35 110
(0.8 x 1.7) (10.7) (490)

2 Tf 23 hes) 26 110
(0.8 x 1. (7.9) (490)

WA >< Sc 35 48 110
(0.8 x 1. ¥ (10.7) (210) (490)

Dall > Jo 35 40-50 110
(Ol Sixers (10.7) (180-220) (490)

Wel 38) 31 90 110
(0.8 x 1. (9.4) (40.0) (490)

BoP 38 Do 35 50 110
(0.8 x 1.7) (10.7) (220) (490)

AS >< oe) 30 100 110
(0.8 x 1.7) (9.1) (450) (490)

Dof/ > Sos) 30 80 150
(0.8 x 1. i (9.1) (36,288) (770)

PST) 28 Yi 35 40-50 110
(0.8 x 1. (10.7) (180-220) (490)

Doll 38 Se 31 80 110
(0.8 x 1. (9.4) (360) (490)

Dell es Sos) 35 30-35 110
(0.8 x 1.7) (10.7) (130-150) (490)

323) X6.7/, 28 30-35 165
(1.0 x 2.0) (8.5) (130-150) (750)

Dall 3% Dro) 28 30-35 110
(0.8 x 1.7) (8.5) (130-150) (490)

Soe} &< Oed/ 28 110
(1.0 x 2.0) (8.5) (490)

3.3 x 6.7 32 110
(1.0 x 2.0) (9.8) (490)

3.3 x 6.7 30 110
(1.0 x 2.0) (9.1) (490)

Boe) 2x8 Cod 29 110
(1.0 x 2.0) (8.8) (490)

Sloe} Bs @42/ 30 110
(1.0 x 2.0) (9.1) (490)

* Not recovered.
** Not recorded.

V7

Figure 9. Deployment of anchor system, viewed from crane
barge looking toward winch barge, with mooring
buoy (left foreground) secured to crane barge.

ee.

PLACEMENT PENETRATION LAUNCHER RECOVERY SETTING
Figure 10. Installation sequence of CEL 100K Propellant Anchor.

18

Two types of propellant were used, one a slower burning, single-
base type (M6) and the other a faster burning, double-base type (M26).
The anchor gun system had been designed to be used with the M26; however,
computer simulation indicated that satisfactory performance could be
achieved with the M6, and its low cost and ready availability made the
M6 a very attractive choice. The exact burn rate of the new propellant
had not been determined in closed bomb tests. To be safe, reduced
charges, which still provided ample performance, were used initially
while peak gun barrel pressures were measured with copper crush gages
mounted in each cartridge assembly.

Installation P1 (permanent site, anchor no. 1) was fired with 15
pounds (6.8 kg) of M6, producing a peak gun barrel pressure of 34 ksi
(234 MPa), somewhat higher than expected. The designed maximum allowable
operating pressure for the gun is 35 ksi: (241 MPa) therefore, the use of
reduced charges was justified until M6 performance could be accurately
defined. Gun barrel pressures derived from M26 firings also were
higher than expected. The reason for these differences was attributed
to:

1. Elevated burning rates (higher than typical for similar propellant)
that may have existed in the untested batches of propellant utilized.

2. A lower-than-calculated chamber volume caused by the large negative
tolerances on the inside diameter of the hollow piston that were accepted
in order to reduce piston cost.

3. The response of the crush gages to peaks, including the effect of
standing wave peaks caused by the nonhomogeneous distribution of the
charge within the gun barrel, as opposed to the computer prediction’s
accounting only for the average pressure at any instant throughout the
entire chamber volume.

Once the system was calibrated with a few firings, slight modifications
could be made to vary performance with reasonable confidence. This
confidence resulted from measured performance repeatibility. Charge
weights were then varied to yield measured peaks of about 30 ksi (207
MPa). This pressure provided maximum gun life as well as ample energy
for installing the flukes so as to achieve holding capacities well in
excess of requirements.

Fluke penetration was measured in each case when the anchor load
line was taut by subtracting the measured water depth and the measured
length of line above water from the entire known line length. This
measured line penetration, plus the distance from the connection on the
fluke to the fluke tip, yielded fluke penetration to the tip.

The required load to retrieve each piston was recorded. Over the
course of the operation, six of the pistons were not recovered. The
first expended piston was left in place during installation P2 primarily
to determine whether the piston when still in contact with the fluke
would affect its performance. This would be particularly important if
the seafloor contained large pockets of coral sand/aggregate rather than

19

intact coral, because the piston could possibly restrict or prevent

fluke keying. There appeared to be no discernible degradation in perfor-
mance. In fact, it is possible that leaving the piston in place enhanced
performance if the coral was intact. Pistons were not recovered during
the last five installations at the temporary site (T4 through T8).

These pistons were well-used, and the piston was not affecting holding
capacity; therefore, to save time they were left in place. Piston loads
varied from a low of about 30 kips (135 kN) to over 100 kips (445 kN)

for pullout. The piston has at most one-fifth the resisting area of the
anchor flukes, and it is loaded only at one end. Compared to the central-
ly loaded flukes, therefore, there is about a factor of 10 between what
the piston and fluke should hold. Piston retrieval provided a good

basis for judging the ultimate capacity of each anchor fluke. Based
upon the piston loads, ultimate holding capacity would vary between
300,000 (1.35 MN) and 1,000,000 (4.45 MN) pounds. The weak link in the
system is therefore the anchor cable, which was rated at 230,000 pounds
(1.02 MN) minimum breaking strength when new.

The piston load was not solely relied upon to judge anchor perfor-
mance. Each anchor was proof=loaded to 100 to 120 kips (445 to 535 kN)
in direct uplift. One fluke was loaded to 150 kips (670 kN) and another
was loaded briefly to 165 kips (735 kN); this latter load was caused by
wave surge on the barge.

Three unsuccessful firing attempts occurred because of malfunction
of the S/A device, and one installation was delayed by the discovery and
correction of a broken circuit in an electrical cable immediately before
deployment of the anchor system. The S/A malfunctions were readily
diagnosed and remedied by the onsite CEL project engineers. Although
the same problems should not recur, such problems are typical of proto-
types such as the CEL 100K Propellant Anchor System in its present
configuration and should be expected, at a diminishing frequency, in
possible future similar operations.

FINDINGS
Holding Capacity

Although it is not definitely known at this point, the long-term
capacity of the anchors can be inferred from the short-term proof-loading
and piston pullout loads.

Based upon the minimum piston pullout load of 30,000 to 35,000
pounds (135 to 155 kN), the respective areas of the piston and the
coral/sand fluke, and the respective mechanical advantages associated
with pulling on the end of the piston and on the center of the fluke, it
is estimated that the short-term capacity is at least 300,000 pounds
(1.35 MN); hence, the strength of the main anchor load line (230,000
pounds, or 1.02 MN) is a lower limit to short-term capacity. Each fluke
was proof-loaded to over 100,000 pounds (445 kN). This resulted in

20

vertical movement of the eye in the fluke of 1 to 2 feet (0.3 to 0.6m).
The maximum keying movement (measured as upward line displacement) for
developing the ultimate capacity of the 5-1/2-foot-long (1.7 m) coral
fluke is about 6 feet (1.8 m) in granular materials. Therefore, a
movement of only about 18 to 36% of this maximum brought enough fluke
area to bear to develop the proof-load. If the same percentages are
assumed to indicate proof-load in terms of ultimate capacity, then this
rough data agrees reasonably well with the minimum short-term capacity
estimated from the piston retrieval loads — the 100,000-pound (445 kN)
proof-load is about 33% of the estimated capacity. Long-term loading,
including some component of cyclic loading, might reduce the anchor
capacity to a level about equal to the long-term strength of the line
(approximately 200,000 pounds, or 890 kN).

Site Investigation

The site conditions encountered were described as extremely variable,
based on data from diver jetting probes. Anchor penetrations varied
somewhat, and piston pullout loads varied by more than a factor of two.
Anchor setting distances were small, but also varied by a factor of
roughly two. Actual capacities are not known. Based upon these data,
it is apparent that a suitable site investigation technique, if available,
would have the following characteristics:

a. Tests that indicate sediment strength
b. A sufficient number of tests for statistical significance

c. A known relation between anchor penetration depth and test
data, to within a factor of 2

d. A known relation between anchor holding capacity and test data
to within a factor of 1.5 or better

These requirements might be satisfied by static- or impact-driven
sounding/sampling probes or a small test-type propellant anchor.

At Diego Garcia, it is estimated that an investigation involving
one small test anchor at each anchor leg location (a total of eight
would be required) would have cost about $3,000 and could have saved
about $10,000 in costs of fabricating excess projectiles. It is felt
that a suitable site investigation technique for remote locations, such
as Diego Garcia, should be used to provide a means to specify a priori
the optimum cost-effective type and size for anchor projectiles. In
this way, performance can be enhanced and costs can be minimized.

Operations
Operational aspects of the anchor system were very good, especially
considering that the crew was initially untrained. In fact, UCT-One

personnel indicated that the propellant anchors were much easier to
install than conventional drag anchors with their required weight clumps

21

and long lengths of chain. A UCT-One crew of four men was assigned to
work with the two CEL project engineers. After this crew had gained

some experience from a few implantments, a comfortable turn-around time
of 2-1/2 hours was achieved between two successive anchor implantments,
barring complications. Subsequent experience gave sufficient proficiency
so that the final two anchors were installed, with no piston retrieval,
within a turn-around time of 1-1/2 hours.

The figure-8 method of faking the wire rope anchor load line in a
horizontal plane around boards bolted to the base of the launch vehicle
proved entirely satisfactory for this large line.

Recovery of the piston after the installation of an anchor fluke is
operationally expensive. As piston retrieval is not essential for the
anchor to develop its holding capacity in materials similar to those
occurring at the reported sites, and as nonrecoverable pistons can be
fabricated relatively cheaply, it would appear that for similar installa-
tions, it would be uneconomical to recover the pistons. Data must be
obtained to verify similar performance in other sediment types before
piston recovery can be eliminated generally from the functioning of the
system.

After being refurbished and strengthened, the launch vehicle had
been used only once prior to its use in Diego Garcia. Therefore, there
was some uncertainty about its ability to withstand a large number of
firings. A thorough inspection of the system after the 18 shots conducted
at Diego Garcia showed no cracked welds or other evidence of damage or
distress.

The anchor was fired remotely via an electrical wire to the surface.
This method is probably limited to about 500 feet (150 m) of water, and
the difficulty and expense of handling the extra line increases with
water depth. At Diego Garcia this approach was simple and quick and
eliminated the need for a self-contained power supply with a seafloor-
sensing triggering device.

Two S/A devices were used during the installations. The solenoid
valves and gas cannister assembly were not damaged, as determined by a
quick check fire of the assembly after each use.

Three unsuccessful firing attempts occurred because of malfunctions
of the S/A device, and one installation was delayed by the discovery and
correction of a broken circuit in an electrical cable immediately before
deployment of the anchor system. Also, problems occurred with the
mating of anchor components. These difficulties were diagnosed and
remedied by the CEL project engineers. Had this technical support not
been provided, installation of anchors would have been delayed further,
and hazardous situations may have occurred. Although the same problems
should not recur, problems of similar significance should be expected to
occur with diminishing frequency as this, or any other similar prototype
is utilized in further installations. In order to provide such an
anchor system for operating forces that has no such requirement for
technical support, a standardized anchor and installation procedure must
be developed and carried through service approval.

2,

The capabilities of large propellant anchors demonstrated in this
installation can be used to advantage to satisfy anchoring requirements
in the areas of amphibious logistics, tactical expedient POL facilities,
undersea surveillance facilities, salvage operations, pollution abate-
ment, fleet moors, ocean facilities construction, and deep sea moors.

In many applications in all of these areas, advantages of low cost,
light weight, and rapid installation are believed to outweigh the possi-
ble disadvantages of providing the required installation support equip-
ment for developing self-contained systems capable of being installed
from bare working platforms.

CONCLUSIONS

From the experiences gained in carrying out the reported installa-
tion, the following conclusions are drawn:

1. The propellant anchor provides a cost-effective and time-
effective means to anchor permanent moorings of moderate size, particu-
larly in remote locations and where the seafloor is coralline.

2. Operational requirements for the installation of propellant
anchor moorings are similar to those for moorings incorporating conven-
tional anchors. In its present configuration, the CEL 100K Propellant
Anchor System requires a crane or boom for deployment and retrieval, and
a means of applying a large proof-load to the embedded anchor flukes. A
double-hooked crane for handling the anchor system and a heavy winch or
beach gear purchase section for proof-loading facilitate installation
operations.

3. Shorter lines and less connective gear are required for propel-
lant anchor moorings than for conventional moorings, thus reducing
costs, staging time, and support requirements.

4, The propellant anchor has good potential for development to
satisfy Navy requirements in the areas of amphibious logistics, tactical
expedient POL facilities, undersea surveillance facilities, salvage
operations, pollution abatement, fleet moors, ocean facilities construc-
tion support, and deep sea moors. In many applications it is lighter in
weight, easier and quicker to install, and lower in overall cost than
other approaches. When desired, it can be used in self-deploying systems
having minimal requirements for operational support. Advanced develop-
ment work is required if the anchor system is to be used by operating
forces without technical assistance.

5. It is advisable that a site investigation tool be used to
determine the properties of the seafloor material at a site to provide a
basis for specifying the optimum type and size of anchor fluke. For
soft sediments, the expendable free-fall penetrometer being developed at
CEL should suffice. For harder materials such as those encountered at
Diego Garcia, a propellant-launched penetrometer or penetrating test
anchor might prove satisfactory; such approaches are available but their
successful use has not been demonstrated.

23

6. The CEL 100K Propellant Anchor System with the present configura-
tion of sediment fluke can be used to install embedment anchors having
holding capacities in excess of 150,000 pounds (670 kN) applied in any
direction. Although ultimate capacities were not determined, long-term
capacities were estimated to be on the same order as that of the 1-3/4-
inch (44 mm) wire rope used as the main anchor load line (approximately
200,000 pounds, or 890 kN).

7. Expending the piston, rather than retrieving it, appears to be
the more cost-effective alternative in most applications. However, the
proper keying of the fluke in soft sediments when the piston is not
retrieved remains to be demonstrated.

8. The present launch vehicle is durable and reliable, as evidenced
by its present excellent condition after nineteen installations. Although
not subject to accurate prediction, its remaining useful life is estimated
to be well in excess of usage to date.

9. Except as noted in the Appendix, the procedures used and refined
during the reported installation appear to be optimum for the system and
should be used in future applications. Included especially are the
procedures used for system assembly, crane handling, faking of the load
line, checking of the S/A device, and firing.

10. Considerable experience with, and knowledge of, the components
are required for the successful utilization of the anchor system in its
present configuration. This necessitates the availability of CEL techni-
cal support. The proposed development of a standardized service-
approved anchor and installation method for Navy operating forces would
overcome this necessity.

REFERENCES

Carmichael, Colin (ed.) (1950) Kent’s mechanical engineers’ handbook:
design and production volume, 12th ed. New York, NY, John Wiley and
SOmgs Imes5 1950,- po 72280

Fluor Ocean Services, Inc., Engineers, Constructors (1973) Mooring and
fuel transfer facility, Reindeer Station, Diego Garcia, Indian Ocean -
consulting and design review report, Department of the Navy, Atlantic
Division, Norfolk, VA. Houston, TX, Aug 1973. (Contract No. N62570-73-
€-1264.)

Mayo, H.C. (1973) Explosive anchors for ship mooring. Marine Technology
Society Journal, Vol. 7, No. 6, Sep 1973. pp 27-34.

Naval Ship Systems Command (1970) Assembly, storage, and operation,

anchor salvage embedment, Technical Manual 0094-007-1010. Washington,
WG, Jem 1970.

24

Smith, J.E. (1971) Explosive anchor for salvage operations - progress
and status, Civil Engineering Laboratory Technical Note N-1186. Port
Hueneme, CA, Oct 1971.

Taylor, R. J. (1976) CEL 20K propellant-actuated anchor. Civil Engineer-
ing Laboratory Technical Report TR-837. Port Hueneme, CA, Mar 1976.

Taylor, R. J., and Lee, H. J. (1972) Direct embedment anchor holding
capacity, Civil Engineering Laboratory Technical Note N-1425. Port
Hueneme, CA, Dec 1972.

Thonasons, Re As, bucella, EF. Ji., and) Lindbers, E. 1.) (1968) Final! report,
propellant-actuated embedment anchor, Naval Civil Engineering Laboratory
Contract Report CR-69.026. Aerojet-General Corporation, Ordnance Division,
Research and Development, Downey, CA (Contractor’s Report No. 3324-
01(01)FP). (Contract No. N62399-68-C-002). Nov 1968.

Underwater Construction Team-One. Diego Garcia - UCT-One construction
operation plan, Little Creek, VA, Jan 1975.

25

Appendix
ANCHOR INSTALLATION LOG

In the following paragraphs, details are given of the specifics of
various installations, particularly those in which problems occurred.
Although the functioning problems that were solved should not recur, the
progress of the work is typical of what would be expected in a possible
future similar operation with such a prototype system.

INSTALLATION P1

This installation was the first for the UCT-One personnel, and it
understandably went slowly. As personnel became more familiar with the
assembly procedures, and handling procedures were improved, subsequent
operations went progressively faster. Some components could not be
assembled because of improper tolerances. Most components were
fabricated and had to be shipped to Diego Garcia without their fit
being checked; as a result, some field modifications were required.
Most of the first day was expended in making these adjustments and
assembling and firing the first anchor. The anchor, placed off the
bow of the barge, was supposed to be lowered rapidly to the seafloor
but inadvertently was allowed to free-fall in 72 feet (22 m) of water.
While this was not intended, in fact it caused considerable excitement,
the system landed correctly (upright), was fired by the electrical firing
cable that had been retained at the surface, and embedded properly.
When the launch vehicle was recovered, it was thoroughly inspected for
any weld cracks or structural deformations; there were none.

INSTALLATION P2

The anchor was assembled in about 2-1/2 hours and placed on the
seafloor. The anchor did not fire and was left on the seafloor for 30
minutes in case there was a hangfire. It was then brought to the surface
and inspected; it was in a safe status as evidenced by the hydrostati-
cally enabled mechanical interlock in the S/A device being in the out-
of-line (safe) position. The S/A device was inspected; the gas cannister,
which provides the energy to drive a firing pin into the primer located
in the cartridge assembly, was discovered to be empty. It had been
filled with dry air to a pressure of 1,100 psi (7.6 MPa) but apparently
the one-way valve in the cannister did not close after filling and the
pressure bled before the unit could be placed in a dielectric fluid to
check for slow leakage.

Possible recurrence was prevented by check-measuring the outside
length of each cannister, when empty and when filled, with a sensitive
micrometer. The cannister would be measured as it was being filled and
just prior to installing it in the S/A device. This proved entirely
satisfactory and is very simple to perform.

26

A new S/A device was placed in the anchor, and it was placed back
on the seafloor. The anchor was fired and test-pulled satisfactorily.

There was sufficient time to install another anchor that day, but
the process of getting the YC barge into its STATO mooring was too time
consuming, and the firing was delayed until the following morning.
Because of this problem, it was decided to use the LCM8 to position the
YC barge over the drop point for a new mooring leg and then to use the
first installed anchor to hold the barge for the second firing. This
procedure worked very well, and greatly sped up the operation.

INSTALLATION P3, P4

Both firings produced almost identical results. Gun barrel pressure,
penetration and piston retrieval load were similar. Both firings occurred
on one day and each anchor took about 2 to 2-1/2 hours to assemble and
deploy.

INSTALLATION P5

The anchor was placed on the seafloor, and it could not be fired
because of an open circuit on one side of the firing cable (this is
easily detected because the resistance through the firing cable and
solenoid valves in the S/A device is accurately known). Line resistance
was about 200 ohms compared to the correct resistance of 70-80 ohms,
indicating a correct electrical connection to only one solenoid; thus
the system could not fire with the existing (safe, 36-volt) power supply.
The anchor was immediately brought on deck; misfire procedures were
unnecessary in this case, and the wire was replaced. The problem was
simply a dirty connector. Standard procedure had been to check the line
resistance at several stages during assembly and overbearing, but this
problem did not occur until the anchor was in the water. The wire was
replaced and the anchor was quickly fired and test-pulled.

INSTALLATION P6, P7

Both anchors were installed without incident. One notable point
was that the piston retrieval load for P/7 was 100-110 kips. The piston
alone in this case would have provided sufficient resistance to serve as
the primary mooring anchor. Gun barrel pressures for both firings, each
using 12 pounds (5.4 kg) of M26 were identical, 27 ksi (186 MPa). These
pressures were consistently higher than originally predicted, but their
excellent repeatability allowed slight field changes to obtain desired
field performance.

27

INSTALLATION P8

This installation was marked by a problem with the S/A device. The
anchor did not fire and was brought to the sea surface after 30 minutes
to inspect the safe status of the anchor. It was completely safe, the
in-line/out-of-line plunger in the S/A device was completely out of
line. Upon disassembly, it was found that the S/A device had been
activated, and the firing pin was driven against the plunger. The
plunger did not go in line. The plunger was supposed to be completely
in line at a depth of 35 to 40 feet (11 to 12 m). The water depth was 72
feet (22 m), and the plunger had not even moved. The reason became
apparent when the S/A was again screwed into the breech. Pressure built
up between the S/A base and cartridge base because there was considerable
grease on the S/A threads preventing pressure relief. This problem was
rectified by filing a V groove across the S/A threads to allow pressure
relief; this problem did not recur. A grooved S/A device was installed,
the anchor replaced on the seafloor, and fired. The anchor was proof-
loaded to 150 kips (670 kN).

INSTALLATIONS P9, P10, Tl

Each anchor was fired and test-pulled to 100 to 120 kips (445 to
535 kN). Total assembly time was now reduced to about 1-1/2 to 2 hours.

INSTALLATION T2

The large 3-1/2 x 7-foot (1.0 x 2.0 m) fluke was used for the first
time. When installed in the gun system, the fluke rests about 2 inches
(50 mm) above the seafloor. There was concern that gun barrel pressures
could increase when the fluke contacted the competent coral prior to the
piston fully leaving the barrel. This concern was rapidly abated after
this firing because the penetration depth and the measured peak gun
pressure were similar to those experienced at the permanent site and
were close to what would be expected for any unlithified seafloor. This
fluke was statically loaded to 100-120 kips (445 to 435 kN); however,
the load did jump to 165 kips (735 kN) for a brief period because of
wave action on the YC barge. There was no noticeable fluke movement.

INSTALLATION T3, T4, T5

All three anchors were installed rapidly and test-pulled to 100 to
120 kips (445 to 535 kN). In order to save time, the last five pistons,
used with anchors T4 through T8, were not recovered. Each piston had
been used previously; and, as leaving them in place apparently had no
adverse effect upon anchor holding capacity, they were not pulled.

28

INSTALLATION T6

The anchor didn’t fire the first time down. The water depth was 47
feet (14.4 m) instead of the 60 feet (18 m) measured 50 feet (15 m)
away. The safety plunger prevented firing in that shallow depth.
Therefore, a new, weaker spring was installed in the S/A device and the
anchor was returned to the seafloor, fired, and test-pulled.

INSTALLATIONS T7, T8

Both anchors were installed and tested within a 1-1/2-hour time
period. The first anchor was almost completely assembled the previous
night and loading the cartridge and installing the S/A were all that
were required. However, the 1-1/2-hour total turn-around time that
elapsed between firings was indicative of how the crew’s familiarity
with the system had progressed.

29

FKATC

No. of
Activities

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107

Total
Copies

2

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107

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Additions

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