Plastic film coatings for protection from marine fouling and corrosion

Technical Report : PLASTIC FILM COATINGS FOR PROTECTION

FROM MARINE FOULING AND CORROSION

February 1969

Sponsored by

NAVAL FACILITIES ENGINEERING COMMAND

NAVAL CIVIL ENGINEERING LABORATORY

Port Hueneme, California

This document has been approved for public
release and sale; its distribution is unlimited.

PLASTIC FILM COATINGS FOR PROTECTION FROM MARINE
FOULING AND CORROSION

Technical Report R-612

YF 38.535.005.01.003

by

James S. Muraoka

ABSTRACT

Saran and polytetrafluoroethylene (TFE) films with a pressure-sensitive
adhesive were applied over the surfaces of painted and unpainted carbon steel
panels and unpainted stainless steel and K-Monel panels. These panels were
submerged in the sea to determine if the plastic film coverings can be effectively
used to (1) protect painted as well as unpainted metal specimens from fouling
and corrosion; (2) remove marine growth that becomes attached to the plastic
film simply by stripping off the covering; and (3) prolong the fouling-free and
corrosion-free intervals so as to decrease the total effort required for recondi-
tioning fouled or corroded surfaces. The saran- and TFE-covered panels were
exposed in the sea for 5 and 8.5 months, respectively. When retrieved, the
panels were completely covered with marine growth, including numerous
large barnacles. Generally, the plastic films protected the test panels from
fouling and corrosion. The marine growth could be removed rapidly by
stripping off the protective plastic covering. Crevice corrosion will occur
under the protective plastic film on susceptible metal panels, such as stainless
steel (type 302), when a small amount of seawater enters through ruptures.

This document has been approved for public release and sale; its distribution is unlimited.

Copies available at the Clearinghouse for Federal Scientific & Technical
Information (CFST1), Sills Building, 5285 Port Royal Road, Springfield, Va. 22151

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CONTENTS

INTRODUCTION
MATERIALS AND METHODS .

Test Panels .
Application of Plastic Films.

Exposure Site .
RESULTS AND DISCUSSION

Fouling Accumulation .
Plastic Films

TRIE
Saran

COST ESTIMATES.
FUTURE WORK
CONCLUSIONS .
RERERENCES

DISTRIBUTION LIST

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INTRODUCTION

Oceanographic instruments, ships’ hulls, buoys, and other structures
submerged in the sea eventually become either heavily fouled with biological
growth or severely corroded. A short time after submergence such objects
become covered with ‘‘primary film.’’ This film is composed of microorga-
nisms such as bacteria, yeast, and diatoms.' Following the formation of
primary film, larger biological organisms such as hydroids, algae, barnacles,
tubeworms, mussels, and bryozoans become attached to the surfaces of the
materials. Some of the detrimental effects to equipment caused by the
fouling of materials are summarized in Table 1.

Table 1. Effects of Fouling on Submerged Objects*

Fouling increases resistance to motion, thereby reducing a ship’s
speed and increasing fuel consumption. Increases frequency of
dry-docking periods.

Ship hulls

Fouling reduces sensitivity and sound transmission and decreases
effectiveness of sound gear by increasing cavitation noise.
Measurement of beam pattern and receiving response of fouled
underwater transducers show reduction of axial sensitivity
ranging from O to 10 db in frequency intervals of 1 to 20 kHz.

Underwater sound
equipment

Fouling on pipe inner surfaces reduces pipe diameter and water
flow. Detached organisms (mussel shells) block water flow at
valves, at screens, and at constricted places in pipes.

Salt water pipe system
in vessels, industrial power
plants, and desalting

plants

Pitting occurs under shells of dead barnacles, created by oxygen
concentration cells. Conditions favorable to corrosion are pro-
duced by metabolic products—particularly acids and sulfides.
Sulfate-reducing bacteria promote anaerobic corrosion.

Metallic surfaces

Fouling damages coatings in several ways: when a barnacle
shell adhering to the coating is torn loose for any reason, the
underlying paint comes off with it; paint film is weakened at
the site of attachment due to metabolic products; the sharp
edges of barnacle shells cut into the coating as the animals grow,
eventually exposing the underlying surface. Paints are also
destroyed by seawater bacteria that attack the resin.

Plastic and glass surfaces Windows of underwater structures and camera lenses become
blocked and require frequent cleaning.

* From Reference 2.

Protective coatings

For protection from fouling and corrosion, various coatings and
antifouling paints are used as seawater barriers. For maximum effective
adhesion to the surfaces of metals, the right coating must first be selected,
next the protective coating must be carefully prepared, and finally, the
coating system must be carefully applied during ideal environmental
conditions. Depending upon the severity of use, rate of water flow, water
temperature, biological activity, and other factors involved, the existent
protective coating—antifouling system for ships (bottom) and for buoys
lasts from 1 to 3 years.2 The sections that become fouled and corroded
must then undergo a costly and time-consuming process of reconditioning,
which includes scraping or sandblasting and a new application of protective
coatings.

Of the many fouling organisms which become attached to the
surfaces of submerged objects, barnacles, whether dead or alive, are the
most difficult to remove. Because of the tenacity with which the barnacles
are able to cement themselves to various types of surfaces, a study to
determine the composition of the barnacle cement has been initiated.4

Various methods other than the application of antifouling paint
systems have been used either to kill existing marine growth or to prevent
or discourage further marine growth on submerged objects in the sea.
These include the use of (1) hot water,® (2) chlorine,® (3) alternating
electrical current,’ and (4) plastic and cupro-nickel barrier wrappings.®

The present study involves the use of thin plastic films with a
pressure-sensitive adhesive backing placed over smooth, clean surfaces
(whether painted or unpainted) of carbon steel, stainless steel, and K-Monel.
The purpose of this study is to determine if the strippable plastic films can
be effectively used to

1. Protect painted as well as unpainted metal surfaces from fouling
and corrosion.

2. Prolong the fouling-free and corrosion-free intervals so as to
decrease the total effort required for reconditioning fouled or
corroded surfaces.

3. Remove barnacles, tubeworms, encrusting bryozoans, and other
sessile Organisms that become attached to the plastic film, simply
by stripping off the plastic film.

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MATERIALS AND METHODS

Two types of polytetrafluoroethylene (TFE) films and a saran film,
each with pressure-sensitive adhesive backing, were used in this study. The
information on thickness, width, adhesives, and costs is presented in Table 2.
These plastic films were selected primarily because of their resistance to sol-
vents and other chemicals, low water absorption, and moisture permeability.
In addition, they have a high electrical resistance and are nonflammable, non-
toxic, tough, and abrasion-resistant. The biggest difference between TFE
and saran is their cost. As shown in Table 2, TFE costs about 10 times more
than saran.

Test Panels

A total of fifteen 6 x 12-inch test panels was used in this study
(Table 3). Carbon steel, stainless steel, and K-Monel were selected because
they are known to corrode in seawater, the object being to determine if the
plastic films would protect these metals from corrosion and fouling. Marine
paint was applied to the carbon steel panels to determine if the pressure-
sensitive adhesive backing on the plastic films would stay attached to the
smooth painted surface for long periods of exposure in the sea and if the
strippable plastic films would give adequate fouling protection.

Application of Plastic Films

Before the plastic films were applied to the unpainted metal surfaces,
the panels were cleaned with alcohol to remove any grease and dust particles.
The eight carbon steel panels were sandblasted to a “‘white metal’’ surface,
and then four of them were spray-painted with the following paint system:
first coat—Formula 117, a pretreatment primer (MIL-P-15328B); second
coat—Formula 119, a vinyl primer (MIL-P-15929); third coat—Formula
122-82, a white cover paint. The cost of preparing the carbon steel panels,
including labor and material, was estimated to be $0.83/sq ft.

It was slightly difficult to apply the plastic film smoothly over the
test surfaces without forming air bubbles underneath the plastic film,
especially when applied by one person alone. The glass-fiber coated with
TFE was much easier to apply than the skived TFE film or the saran film
because it was much firmer and stiffer to handle. The edges of the skived
TFE and the saran film tended to curl during the application process, thereby
making it difficult for one person to apply it smoothly over the test surface.
However, all the films could be applied fairly rapidly: it was estimated that

the application process of each panel took 5 minutes or less to complete. The
pressure-sensitive adhesive backing of TFE and saran film adhered to the clean
painted and unpainted test surfaces very well. Figures 1 and 2 show this
adhesive quality.

Table 3. Panels Used in Exposure Tests

Painted Panels Unpainted Panels
Met VWRE Saran Control TRE Saran Control
Films Film (no film) Films Film (no film)

Carbon 5 1 5 1 1
steel

Stainless he 5 1 1
steel

K-Monel _ 2 — 1

Figure 1. Unpainted carbon steel panels with TFE film. Panel 1 is a control panel.

Figure 2. Painted carbon steel panels with TFE film. Panel 7 is a control panel.

Exposure Site

A site was desired where the test specimens would be exposed to
biological growth and subjected to the strong tidal currents, high waves,
and rough sea conditions encountered during storms. Such a test site was
provided near the end of the 400-foot-long Point Mugu pier, which is located
at the head of the Mugu Submarine Canyon (Figure 3).

The test panels were placed in a metal rack. The individual panels
were held separately and securely in place by four ceramic insulators (see
Figures 1 and 2). The ceramic insulators also served to prevent galvanic
corrosion, which is caused by the presence of an electrical circuit between
two dissimilar metals. The racks with the test specimens were lowered from
the pier and submerged approximately 15 feet below high tide level. At high
tide the water depth is about 20 feet at the exposure site.

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RESULTS AND DISCUSSION
Fouling Accumulation

The saran-covered panels were retrieved from the sea after 5 months
of continuous exposure and the TFE-covered panels after 8.5 months. The
saran and TFE films were in very good condition when recovered. Probably
these films could be left in the sea for many additional months to serve as
protective coatings. The saran-covered test panels and the 1 FE-covered test
panels (Figures 4 and 5) were completely encrusted with marine growth.

The fouling accumulation was composed mostly of hydroids, bryozoans,
barnacles, tubeworms, and mussels.

There was an average of 75 barnacles securely attached to the surface
of each of the eight TFE-covered panels. The barnacles and tubeworms were
covered and hidden among dense growths of hydroids and bryozoans. The
average wet weight of fouling accumulation, including barnacles and mussel
shells, was about 700 grams per panel (1 square foot).

Figure 4. Biological growth over K-Monel steel panels.

Figure 5. Biological growth over painted carbon steel panels.

Saran-covered panels were also laden with marine growth composed

mostly of hydroids and barnacles as well as some colonial tunicates, bryozoans,

and algae. Mussels and tubeworms, which were found on TFE, were absent
from saran, probably because the latter was placed in the sea at a different
time of the year. There were 14 to 44 barnacles, measuring up to 1 inch in
diameter at the base, attached to the surface of the saran-covered panels;
the average wet weight of fouling accumulation was about 400 grams per
panel.

Table 4 lists the kinds of fouling organisms found on the test panels.
There was much less fouling on the control panels of unpainted carbon steel
and K-Monel than on the painted and plastic-covered carbon steel panels.
This may be due to the thin layers of corrosion products formed over the
control panels. Such corrosion products may have discouraged the settling
of fouling organisms.

Table 4. Fouling Organisms on Test Panels Exposed at Point Mugu Pier*

Animals

Phylum Coelenterata—Class Hydrozoa
Campanularia flexuosa
Obelia sp.

Plants

Phylum Rhodophyta
Porphyra sp.
Dasya sinicola
Chondria nidifica

Phylum Arthropoda
Balanus crenatus
Balanus glandula
Balanus tintinnabulum
Caprella sp.

Chiton

Phylum Chlorophyta
Ulva sp.

Phylum Mollusca
Membranipora sp.
Crisia sp.

Bugula sp.

Phylum Chordata
Ascidians
Colonial tunicates

Phylum Annelida (segmented worms)
Nereis sp.
Serpulids (tube dwellers)
Calcareous tube dwellers
Parchment tube dwellers

* Major sessile organisms and plants on test panels.

The biological growth, such as bryozoans, hydroids, and algae, could
be scraped off the panels without too much difficulty; however, some small
structures of the animals and plants would remain firmly attached to the
panels. Mussel shells and the calcareous tubes of tubeworms were slightly
more difficult to remove from the surfaces of the panels. The animal growths
most difficult to remove were barnacle shells. The barnacle shells of live or
dead animals could be removed only by breaking the shells off the panels with

a large spatula. In almost every case, the upper section of these barnacles
would part from the baseplate, which remained securely attached to the
panels. The majority of the barnacles attached to the TFE films could be
pried off by applying a steady pressure with one’s fingers. Normally, the
barnacle’s whole shell, including the baseplate, could be dislodged.

Plastic Films

TFE. In general, TFE films performed very well in protecting the
panels from fouling and corrosion (Figures 6 through 9). The TFE film
covered with marine growths, including barnacles and mussels, could be
stripped off the 6 x 12-inch panels without difficulty. The entire stripping
process took 3 to 5 minutes per panel. Underneath this plastic film, there
was a surface as clean as if the panel had never been exposed in the sea. On
the other hand, the control panels were heavily corroded and some of them
were covered with heavy biological growth which required considerable time
and effort to remove. The glass-fiber TFE film was slightly stronger and
tougher than the skived TFE film.

Figure 6. Unpainted carbon steel panels after biological growth and plastic
covering had been removed. Panel 1 is a control panel. Panels 2
and 3, protected by TFE films, show a large noncorroded area
of white metal.

11

Figure 7. K-Monel panels after biological growth and plastic coverings had
been removed. The entire surface of control panel 4 is covered
with pits due to corrosion. Panels 5 and 6 were protected by
TFE film. The surfaces of these panels are free of corrosion.
Lines of discoloration are shown on panel 5.

oe SEES A ’

Figure 8. Painted carbon steel panels after biological growth and plastic
covering had been removed. Control panel 7 has a large number
of barnacle baseplates still attached to the surface. Panels 8 and
9 were protected with TFE film. Barnacles grew over one small
area of panel 9 where a small section of plastic covering was torn.

12

Saran. Saran also performed well in protecting the surfaces of the
panels from fouling and corrosion. However, heavy crevice corrosion along
the edges of the stainless steel panels was experienced when seawater came in
contact with the metal through small rupture holes made in the plastic film.
The pressure-sensitive adhesive material on the saran film seemed to adhere
more tenaciously to various clean test surfaces than the adhesive material on
the TFE film. The saran film was especially well attached to the surface of
sandblasted carbon steel. For this reason, considerable difficulty was
encountered during the stripping process because the saran film would tear
off into small pieces. However, the plastic film did peel off in fairly large
sections from painted carbon steel panels and from stainless steel panels
without too much difficulty. A slightly thicker saran film should be used
for the fouling and corrosion protection of submerged materials.

Figure 9. Stainless steel panels after biological growth and plastic covering
had been removed. Control panel 10 has numerous barnacle
baseplates attached to the surface. Panels 11 and 12 were
protected with TFE film. Evidence of fouling growth is
visible where TFE film was torn due to unknown causes.
Crevice corrosion along the edges of panels 11 and 12 is
visible.

13

Table 5 summarizes the effectiveness of TFE and saran film in
protecting carbon steel, stainless steel, and K-Monel panels from marine
fouling and corrosion. Table 6 compares the weight lost by TFE-protected
and control panels as a result of corrosion after 8.5 months of exposure. The
weight loss due to corrosion of saran-protected carbon steel panel (unpainted)
was about identical to that of TFE-protected test panels.

Because the application of the thin plastic films over test surfaces is
difficult, a specially designed dispenser is needed to apply the plastic film
over large surface areas smoothly, quickly, and efficiently. The film should
be applied without producing air pockets underneath the plastic films.

COST ESTIMATES

It is estimated that the cost of labor for applying the plastic film
over aclean, flat 1-square-foot area would be about $0.25/hr. This assumes
that the plastic film can be placed over the 1-square-foot area in about 3
minutes and that, including overhead, the labor cost is about $4.80/hr.

The total cost of application, including labor and materials, would
be as follows:

1. $0.50/sq ft for saran film
$0.25 (labor) + $0.25 (materials)

2. $3.00/sq ft for TFE skived film
$0.25 (labor) + $2.75 (materials)

3. $2.75/sq ft for TFE, glass-fiber film
$0.25 (labor) + $2.50 (materials)

By comparison the cost of labor (sandblasting and application of
paint) and materials for applying an effective paint system over carbon steel
is estimated to be about $0.83/sq ft.2

FUTURE WORK

This present study on strippable plastic films as protective coatings
over various test panels exposed at Point Mugu pier has been completed.
Aluminum (6061-T6) and several plastic panels have been covered with the
plastic films for evaluation and secured to STU |-5 for a 6-month exposure
test at a depth of 6,000 feet off the coast of Port Hueneme. In the future,
certain selected oceanographic instrument packages will also be covered
with these plastic films prior to submergence in the sea, primarily for fouling
protection.

Test Panel

Unpainted carbon steel

Painted carbon steel

TFE Films
(glass-fiber and skived)

The TFE films were found adhering to
the surface over a major portion of the
sandblasted panels. !n some areas where
seawater had penetrated the plastic at

the overlaps and through small puncture
holes, the plastic film did not adhere to
the metal due to red rust formation. The
surface of the metal underneath the
plastic film was protected from corrosion
and fouling; stripping revealed the original
sandblasted bright white metal (Figure 6).
The plastic films could be easily and
rapidly peeled off the metal panel in

large sections.

The TFE films were found adhering nicely
to the surfaces of the painted panels. The
films could easily be removed in large
sections from each panel in about 3 minutes.
During the removal process, where the
baseplate of the barnacle adhered to the
plastic, the plastic would rip around the
edges of the base. The painted surface

Saran Film

Saran film was found adhering
to the surface of the sandblasted
metal. Because the pressure-
sensitive adhesive material was
securely attached to the surface,
it was very difficult to remove
the plastic film. During the
removal process the saran film
would tear off into small pieces.
However, the metal surface
underneath the plastic film was
corrosion free.

The saran film was strongly

adhering to the surface of the panel.

The film with biological growths
could be removed easily from the

surface of the panel in fairly large
sections. It is advisable to remove

all of the barnacle shells attached
to the plastic film before peeling

Table 5. Performance of Plastic Film Coverings on Test Panels

No Film

The control panel was severely
corroded with a uniform distri-
bution of red rust over the entire
panel. Underneath this layer of
red rust there was a layer of
gelatinous black iron sulfide
corrosion products. Sulfate-
reducing bacteria were found
associated with such corrosion
products.

The control panel had the
heaviest fouling growth
among all the test panels. The
barnacles growing on the

painted surface were extremely
difficult to remove. Nearly all of
the barnacles were broken during
the removal process and their

Remarks

The surface of a newly sandblasted
carbon steel panel should be covered
immediately with a plastic film. The
pressure-sensitive adhesive backing on
a plastic film will not adhere too well
over a corroded surface.

The surfaces of the protected panels
were so clean that the panel could be
recoated and resubmerged in the sea
immediately. On the other hand, the
control panels probably would have
to undergo extensive reconditioning
before exposure.

underneath the plastic film was very clean
as if it had never been exposed in the sea
(Figure 8). A small section of the paint
underneath the protective film was
exposed to biological growth when the
plastic film was destroyed by the

abrasive action of the ceramic insulator
which held the panel in place.

baseplates remained attached to

the painted surface. Considerable
time was spent trying to remove the
baseplates of these barnacles.

because the plastic will start to tear
at the site of barnacle attachment
during the removal process. The
edges of the plastic adhered very
well to the metal and painted
surfaces.

Test Panel

K-Monel

Stainless steel

TFE Films

(glass-fiber and skived)

The TFE films were found adhering to
the surface of the entire panel. When
the plastic film was removed, the metal
surface was very bright and free of
corrosion and fouling growth. There
were streaks of dark discoloration over
the metal where seawater had leaked
through the plastic film at the overlap
(Figure 7). The TFE films covered
with marine growth, including barnacles,
could be peeled off the test panel
without much effort.

The TFE films were found adhering to
the surface of the panels. When the
plastic films were removed from the
panels, the underlying surfaces of the
stainless steel panels were very clean and
bright (Figure 9). There was only minute
weight loss. There was some crevice
corrosion present on the surface of the
metal where seawater had penetrated the

plastic film through punctures (Figure 11).

Elongated tunnel pits present in control
Panels were not present on TFE-covered
panels.

Table 5. Continued

Remarks

No Film

Saran Film

TFE films gave complete protection
from corrosion and fouling for
8.5 months of exposure.

The entire surface of the control
panel was covered with pits
(Figure 7). There were also pits
surrounding the base of the
barnacle growths (Figure 10).

Saran film was not placed over
K-Monel panels.

The crevice corrosion found on stainless
steel (type 302) under barnacles and
under the plastic films resulted from
oxygen concentration cells. As shown
in Figure 9, the original writings under
plastic covering are visible.

The saran film was found adhering
well to the surface of the stainless
steel except along the edges of the
panel. The edges of the panel
were affected by crevice corrosion
due to penetration of seawater
through ruptures in the plastic
film. The saran film covering
could be removed fairly rapidly
from the panel without the
plastic being torn into very small
pieces. The underlying surface

of the panel was very bright and
clean (Figures 12, 13, and 14),

The control panel was severely
marked with several tunnel pits
(Figure 15) and crevice corrosion
underneath the barnacle shells
(Figure 16).

Table 6. Weight of Test Panels Before and After 8.5 Months of Marine Exposure

Weight Weight Weight Loss
Type of Before After Due To
Protection Exposure Exposure Corrosion
(gm) (gm) (%)

Panel No. Test Panel

none (control) 1,310.0* 1,195.0**
skived TFE | CRE | Seaele
glass-fiber TFE 1} COZ PSOeZe

unpainted
carbon steel

none (control) 1,116.5 1,093.2
-skived TFE 1,119.0 1,118.0
glass-fiber TFE LAV Wall lGe7

none (control) 1,378.4 1,377.9
skived TFE 1,395.0 1,394.5
glass-fiber TFE 1,387.8 1,387.7

Painted
carbon steel

none (control) 497.61 493.18
skived TFE 489.18 488.7
glass-fiber TFE 495.18 493.57

stainless
steel

* Weight after sandblasting.
** Weight after chemical cleaning.

Figure 10. Close-up of K-Monel panel 4, showing pits and circular
corrosion pattern around barnacle growth.

17

Figure 11. Close-up of a stainless steel panel, showing crevice corrosion
at the edge. The corrosion occurred underneath the TFE
film where seawater had leaked inside through small ruptures.

Figure 12. Biological growth over a stainless steel panel covered with saran
film after 5 months of exposure at Point Mugu pier.

18

Figure 13. Stainless steel panel with saran film after biological growth had
been removed with a spatula.

Figure 14. Surface of stainless steel panel after saran covering had been removed.
Crevice corrosion along the edge of the panel was produced under-
neath the plastic when seawater was introduced through tiny rupture
holes. A clean, shining metal surface was found underneath a
rectangular (patch-like) saran covering (right side).

19

Figure 15. Close-up of stainless steel control panel showing elongated corrosion
(tunnel pits). Tunnel pits were not found on protected panels.

Figure 16. Close-up of stainless steel control panel showing crevice corrosion
underneath barnacle growth.

20

CONCLUSIONS

1. The application of strippable plastic films will prolong the fouling-free
and corrosion-free interval. This will decrease the total time required for
reconditioning fouled or corroded metal surfaces.

2. The heavy biological growth over the plastic films can be removed
more rapidly by stripping away the plastic film than by conventional
methods such as scraping and sandblasting.

3. The plastic films will protect metal panels (carbon steel and K-Monel)
from corrosion. Crevice corrosion will be produced on susceptible metal
panels (stainless steel, type 302) under protective films when a small
amount of seawater enters through ruptures.

4. The pressure-sensitive adhesive on saran film seems to adhere to the
various test surfaces better than the pressure-sensitive adhesive on TFE film.

21

REFERENCES

1. Naval Civil Engineering Laboratory. Technical Note N-894: The
formulation of a ‘’primary film’’ on materials submerged in sea water at
Port Hueneme, California, by T. B. O'Neill and G. Wilcox. Port Hueneme,
Calif., July 1967. (AD 820261L)

2. J. S. Muraoka. “Effects of marine organisms,’ Machine Design, vol. 40,
no. 2, Jan. 18, 1968, pp. 184-187.

3. J. R. Saroyan. ‘’Protective coatings,’’ Machine Design, vol. 40, no. 2,
Jan. 18, 1968, pp. 188-192.

A IR. Saroyan, E. Linder, and C. A. Cooley. “Barnacle cement and
adhesion mechanism,’’ paper presented at the Symposium on Chemical
Oceanography, Naval Research Laboratory, Washington, D. C., Mar. 25-27,
1968.

5. W. L. Chadwick, F. S. Clark, and D. L. Fox. “‘Thermal control of marine
fouling at Redondo Beach Steam Station of the Southern California Edison
Company,’’ American Society of Mechanical Engineers, Transactions, vol. 72,
no. 2, Feb. 1950, pp. 127-131.

6. H. E. White. ‘Control of marine fouling in sea-water conduits including
exploratory tests on killing shelled mussels,’’ American Society of Mechanical
Engineers, Transactions, vol. 72, no. 2, Feb. 1950, pp. 117-126.

7. Naval Civil Engineering Laboratory. Technical Note N-872: The effect
of alternating electrical currents on marine fouling, by T. Roe. Port Hueneme,
Calif., Jan. 1967.

8.————.. Technical Report R-455: Installation of barrier systems on
marine-borer-damaged bearing and fender piles, by T. Roe. Port Hueneme,
Calif., June 1966. (AD 486525L)

9,————. Technical Report R-501S: Cost comparison of protective
coatings for steel, by C. V. Brouillette. Port Hueneme, California, Nov. 1967.

22

DISTRIBUTION LIST

SNDL No. of Total
Code Activities | Copies

— ] 20 Defense Documentation Center
FKAIC 1 ie Naval Facilities Engineering Command
FKNI 13 13 NAVFAC Engineering Field Divisions
FKN5 g 9 Public Works Centers
FA25 ] ] Public Works Center

= 15 15 RDT&E Liaison Officers at NAVFAC

Engineering Field Divisions and
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= 120 120 Special NCEL Distribution List for

persons and activities interested in
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23

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Unclassified

Security Classification

DOCUMENT CONTROL DATA-R&D

(Security classification of title, body of abstract and indexing annotation must be entered when the overall report ix classified)
oc
a share a
Naval Civil Engineering Laboratory Unclassified
. . 2b. GROUP
pone lugneme: galeria aire Se el ee cee

PLASTIC FILM COATINGS FOR PROTECTION FROM MARINE FOULING AND
CORROSION

4. DESCRIPTIVE NOTES (Type of report and inclusive dates)
Not final; July 1967—August 1968

5. AUTHOR(S) (First name, middle initial, last name)

James S. Muraoka

6- REPORT DATE 7a. TOTAL NO- OF PAGES 7b. NO. OF REFS
February 1969 23 9

8a. CONTRACT OR GRANT NO. 98. ORIGINATOR'S REPORT NUMBER(S)

-ProsectNo. YF 38.535.005.01.003 TR-612

96. OTHER REPORT NO(S) (Any other numbers that may be assigned
this report)

. DISTRIBUTION STATEMENT

This document has been approved for public release and sale; its distribution is unlimited.
- SUPPLEMENTARY NOTES 12. SPONSORING MILITARY ACTIVITY

Naval Facilities Engineering Command
Washington, D. C.
. ABSTRACT
Saran and polytetrafluoroethylene (TFE) films with a pressure-sensitive adhesive were
applied over the surfaces of painted and unpainted carbon steel panels and unpainted stainless
steel and K-Monel panels. These panels were submerged in the sea to determine if the plastic
film coverings can be effectively used to (1) protect painted as well as unpainted metal specimens
from fouling and corrosion; (2) remove marine growth that becomes attached to the plastic film
simply by stripping off the covering; and (3) prolong the fouling-free and corrosion-free intervals
so as to decrease the total effort required for reconditioning fouled or corroded surfaces. The
saran- and TFE-covered panels were exposed in the sea for 5 and 8.5 months, respectively. When
retrieved, the panels were completely covered with marine growth, including numerous large
barnacles. Generally, the plastic films protected the test panels from fouling and corrosion. The
marine growth could be removed rapidly by stripping off the protective plastic covering. Crevice
corrosion will occur under the protective plastic film on susceptible metal panels, such as stainless
steel (type 302), when a small amount of seawater enters through ruptures.

FORM (PAGE 1)
DD 1 NOV el 473 ae Unclassified

S/N 0101- 807-6801 Security Classification

Security Classification

Marine fouling
Marine corrosion
Protective coverings

Plastic films

FORM
DD 1 NOV al 4 73 (BACK) Unclassified

(PAGE 2) Security Classification

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