Naval Ships Tech Manual Chapter 081 Waterborne Underwater Hull Cleaning.pdf

j. The most recent Docking Report will be available.

k. When contractor divers are engaged in hull cleaning of nuclear ships, they shall be trained in accordance with the applicable Radiological Controls manual (NAVSEA 389-0288 or NAVSEA S9213-33-MMA-000/(v)).

l. Prior to contractor diving on nuclear ships, a hull survey of the ship shall be conducted in accordance with the applicable Radiological Controls manual (NAVSEA 389-0288 or NAVSEA S9213-33-MMA-000/(v)) using Navy divers. The surveys shall determine extent, if any, of hull surface contamination. Areas with con-tamination must be marked in such a way that the contractor divers can avoid them.

m. Prior to diving on nuclear ships, contractor divers shall be issued dosimetry and briefed in accordance with the requirements of the applicable Radiological Controls manual (NAVSEA 389-0288 or NAVSEA S9213- 33-MMA-000/(v)). Hull surveys performed and boundaries established shall be discussed as part of this briefing. Completion of this briefing shall be documented by signature on the applicable, local diving permit/ Lead Maintenance Activity documentation.

n. Diving around active sonars shall be conducted in accordance with the U.S. Navy Diving Manual, Appendix 1A, Safe Diving Distances from Transmitting Sonar.

o. When diving in the vicinity of PRAIRIE and masker air systems the main generators and bleed air shall be secured until requested by the diving supervisor to verify cleaning effectiveness.

081-3.3 CLEANING GUIDELINES

The diver shall inspect the surface requiring cleaning and determine which equipment is required to effec-tively remove the fouling with the least aggressive force. The most effective tool shall be used to remove the fouling efficiently while at the same time preventing damage to the underlying system (e.g. hull coating, GRP shaft coating, rubber window, etc.). The following paragraphs provide requirements for cleaning the hull and appurtenances; including but not limited to, cathodic protection systems, propulsors, sonar systems, masker emit-ter belts, prairie system components, sea chests, submarine hulls, wood and fiberglass hulls, propulsion shafts, auxiliary propulsion units and secondary propulsion motors, and bow thrusters. Table 081-3-1 summarizes the cleaning criteria and equipment approved for cleaning various ship components.

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81-3-2

Table 081-3-1 CLEANING CRITERIA AND APPROVED EQUIPMENT

Ship Sys-tem

Abla-tive Anti- Foul-ing Coat-ing Sys-tem

Non- Abla-tive Anti- Foul-ing Coat-ing Sys-tem

Foul-ing Release Coat-ing Sys-tem

Masker Air Emit-ter Belts

Prarie Masker Air Emit-ter Holes

Hub Masker Air

Fin Stabi-lizers

Sea Chest Grat-ings

Sea Chest Inside

Bilge Keels

Auxil-iary Pro-pulsion Unit

Sec-ondary Pro-pulsion Motor

Under-water Log / Pit sword

Bow Thrust-ers

ICCP

Anode

ICCP

Dielec-tric Shield

ICCP

Refer-ence Cell

Sonar Sys-tems

Spe-cial Hull Treat-ment

(SHT/

MIP)

Struts and Rud-der

GRP

Coated Pro-pulsion Shaft

Pro-pulsion Shaft Bear-ings

Propul-sor

Prod-uct Iden-tifier

(1) Size

Crite-ria

FR40

(over 20% )

FR50

(over 10% )

FR50

(over 10% )

FR50

(w/5% flow restric-tion )

FR50

(w/10% flow restric-tion )

FR50

(w/10% flow restric-tion )

FR40

(over 20% w/10% flow restric-tion )

FR40

(over 20%)

FR40

(over 20%)

Same as hull coat-ing

Same as hull coat-ing and pro-peller

Same as hull coat-ing and pro-peller

FR30

or greater

Same as hull coat-ing and pro-peller

FR30

or greater

Same as hull coat-ing

FR30

or greater

FR30

or greater

Same as hull coat-ing

Same as hull coat-ing

Same as hull coat-ing

Painted sur-faces:

FR40

or greater (over 10% ), Unpaint-ed sur-faces Rupert ″C″ or greater

Single- Brush/Disc Units

A-1 18 in x x x x x x x x x x x x x x x x x x x(7) x(8)

A-2 9, 11, in x x x x x x x x x x x x x x x x x x(7) x(8)

A-3 11, 13 in x x x x(7) x(8)

A-4 9, 11 in x x(7) x(8)

C 9, 11, in x(2) x(2) x x x(2) x(2) x(7) x(8)

D 5, 7, in x(5) x(3) x x(7) x(8)

D3 7.5, 9 in x(5) x(3) x x x(7) x(8)

D5 7.5, 9 in x(5) x(7) x(8)

SCD (Blue) 3 in x(3) x(4) x(4) x x(7) x(8)

CRD

(Black)

3 in x(5) x(3) x(4) x(4) x x(7) x(8)

Clean N Strip XT (Purple)

4.5, 6, in x(5) x(3) x(7) x(8)

H-1 280 mm x x x x x x x x x x x x x x x x x x x(7) x(8)

H-2 280 mm x x x x x x x x x x x x x x x x x x x(7) x(8)

H-3 280 mm x x x x x x(7) x(8)

H-4 280 mm x(2,6) x(2,6) x(2,6) x(7) x(8)

H-5 280 mm x(6) x(6) x(6) x(7) x(8)

Multi-Brush Units

E-1 19, 22 in x x x

E-2 19, 22 in x x x

E-3 19, 23 in x x x

E-4 19, 23 in x x x x

E-5 19, 23 in x

M-1 350 mm x

M-2 350 mm x x x x x x x x x x x x x x x

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Table 081-3-1 CLEANING CRITERIA AND APPROVED EQUIPMENT - Continued

Sys-tem

Abla-tive Anti- Foul-ing Coat-ing Sys-tem

Non- Abla-tive Anti- Foul-ing Coat-ing Sys-tem

Foul-ing Release Coat-ing Sys-tem

Masker Air Emit-ter Belts

Prarie Masker Air Emit-ter Holes

Hub Masker Air

Fin Stabi-lizers

Sea Chest Grat-ings

Sea Chest Inside

Bilge Keels

Auxil-iary Pro-pulsion Unit

Sec-ondary Pro-pulsion Motor

Under-water Log / Pit sword

Bow Thrust-ers

ICCP

Anode

ICCP

Dielec-tric Shield

ICCP

Refer-ence Cell

Sonar Sys-tems

Spe-cial Hull Treat-ment

(SHT/

MIP)

Struts and Rud-der

GRP

Coated Pro-pulsion Shaft

Pro-pulsion Shaft Bear-ings

Propul-sor

Prod-uct Iden-tifier

(1) Size

Crite-ria

FR40

(over 20% )

FR50

(over 10% )

FR50

(over 10% )

FR50

(w/5% flow restric-tion )

FR50

(w/10% flow restric-tion )

FR50

(w/10% flow restric-tion )

FR40

(over 20% w/10% flow restric-tion )

FR40

(over 20%)

FR40

(over 20%)

Same as hull coat-ing

Same as hull coat-ing and pro-peller

Same as hull coat-ing and pro-peller

FR30

or greater

Same as hull coat-ing and pro-peller

FR30

or greater

Same as hull coat-ing

FR30

or greater

FR30

or greater

Same as hull coat-ing

Same as hull coat-ing

Same as hull coat-ing

Painted sur-faces:

FR40

or greater (over 10% ), Unpaint-ed sur-faces Rupert ″C″ or greater

M-3 350 mm x x x x x x x x x x x x x x x

M-4 350 mm x x x x x x x x x

Water Jet Systems

Gun, Noncavitat-ing

Various 10,000 psi x x x x(5) x x(5) x x(7) x(8)

Hydrolance Various 10,000 psi x x x(5) x(7) x(8)

Hydrolance Various 3,000 psi x(5) x x x(7) x(8)

Hydrolance Various 2,500 psi x x(7) x(8)

Hand Scrapers

Wood Vari-ous x x x x x x x x x x x x x x x x x x x x x(7) x(8)

Plastic Vari-ous x x x x x x x x x x x x x x x x x x x x x(7) x(8)

Brass Vari-ous x x x x x x x(7) x(8)

Ferrous Metal

Vari-ous

N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A x(7) x(8)

Hand Pads and Brushes

White (33) 48011- 33012

6 x 12 in x x x x x x x x x x x x x x x x x x x x(7) x(8)

White (7445)

48011- 16976-7

6 x 9 in x x x x x x x x x x x x x x x x x x x x(7) x(8)

Green (96) 48011- 08293-1

6 x 9 in x x x x x x x x x x x x x x x x x x x(7) x(8)

Green (86) 48011- 05509-6

6 x 9 in x x x x x x x x x x x x x x x x x x x(7) x(8)

Maroon (7447)

48011- 04029-5

6 x 9 in x x x x x x x x x x x x x x x x x(7) x(8)

Duddle-bugTM

48011- 14020-4

4 x 9 in x x x x x(7) x(8)

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Table 081-3-1 CLEANING CRITERIA AND APPROVED EQUIPMENT - Continued

Sys-tem

Abla-tive Anti- Foul-ing Coat-ing Sys-tem

Non- Abla-tive Anti- Foul-ing Coat-ing Sys-tem

Foul-ing Release Coat-ing Sys-tem

Masker Air Emit-ter Belts

Prarie Masker Air Emit-ter Holes

Hub Masker Air

Fin Stabi-lizers

Sea Chest Grat-ings

Sea Chest Inside

Bilge Keels

Auxil-iary Pro-pulsion Unit

Sec-ondary Pro-pulsion Motor

Under-water Log / Pit sword

Bow Thrust-ers

ICCP

Anode

ICCP

Dielec-tric Shield

ICCP

Refer-ence Cell

Sonar Sys-tems

Spe-cial Hull Treat-ment

(SHT/

MIP)

Struts and Rud-der

GRP

Coated Pro-pulsion Shaft

Pro-pulsion Shaft Bear-ings

Propul-sor

Prod-uct Iden-tifier

(1) Size

Crite-ria

FR40

(over 20% )

FR50

(over 10% )

FR50

(over 10% )

FR50

(w/5% flow restric-tion )

FR50

(w/10% flow restric-tion )

FR50

(w/10% flow restric-tion )

FR40

(over 20% w/10% flow restric-tion )

FR40

(over 20%)

FR40

(over 20%)

Same as hull coat-ing

Same as hull coat-ing and pro-peller

Same as hull coat-ing and pro-peller

FR30

or greater

Same as hull coat-ing and pro-peller

FR30

or greater

Same as hull coat-ing

FR30

or greater

FR30

or greater

Same as hull coat-ing

Same as hull coat-ing

Same as hull coat-ing

Painted sur-faces:

FR40

or greater (over 10% ), Unpaint-ed sur-faces Rupert ″C″ or greater

Notes:

1. This table represents all equipment approved for use on a ship system. Some systems may require cleaning of various surfaces and materials that will limit the available tools approved for use. See applicable ship system in Section 3 for specific cleaning requirements and restrictions. Refer to the Qualified Products List (section 5) for specific equipment and manufacturers.

2. Wire brushes shall only be used to clean severely fouled ablative and non-ablative (excluding foul release) hull coating systems after all other brushes have failed.

3. Abrasive brushes and dics may be used to clean bare monel surface on leading edge of fin stabilzers.

4. For use on bare metal surface of propeller only.

5. For use on bare metal surfaces.

6. For use on 100% FR90 or greater.

7. See Underwater Ship Husbandry Manual Chapter 18, Propulsion Shaft Bearings for specific cleaning procedures.

8. See Table 081-3-2 for equipment approved for cleaning specific propulsor surfaces.

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081-3.3.1 HULL CLEANING

CAUTION

The use of barnacle busters, coach bolt brushes or similar devices is prohibited.

CAUTION

Consult the latest Docking Report to determine the type of antifouling coating on a ship’s hull.

CAUTION

During the cleaning the diver shall routinely monitor the performance of the clean-ing and its impact on the coating system. Cleaning shall not result in scratches or swirl marks on the surfaces or abrasion of edges, corners, seams, welds, rivet or bolt heads, that expose on extend into the underlying layer of coating. Extreme dili-gences must be taken when monitoring the results of the cleaning process to differ-entiate between each exposed layer and ensure an intermediate layer has not been completely removed thus exposing the next layer having the same color as the outer layer.

CAUTION

If the paint is extremely soft and excessive material is being removed, discontinue cleaning immediately and contact NAVSEA Code 00C.

CAUTION

If during the cleaning process more than five (5) percent of the exposed surface of the outer most layer of an ablative anti-fouling paint system is removed, discontinue cleaning immediately and contact NAVSEA Code 00C.

081-3.3.1.1 The cleaning guidance provided in paragraphs 081-3.3.1.2 through 081-3.3.1.6 applies to painted surfaces of the hull and appurtenances.

081-3.3.1.2 Where convex hull curvature permits, multi-brush units may be used. The brushes used on these units shall be in good condition and conform to Section 4. The least aggressive brush necessary to achieve a properly cleaned surface while minimizing any impact on coating system shall be used. All rotating brushes shall be turned off or retracted from the hull during idle periods when the machine is resting on the hull as well as when the machine is being turned on the hull at the end of each swath.

081-3.3.1.3 In areas of smaller convex curvature, areas of concave curvature (such as found between the skeg and the ship’s bottom) and areas of limited access, hand-held single brush units are permissible. The brushes used on these units shall be in good condition and conform to Section 4. The least aggressive brush necessary to achieve a properly cleaned surface while minimizing any impact on coating system shall be used.

081-3.3.1.4 All marine fouling shall be removed from painted surfaces painted with Formula 121, although this occurs less common since the paint specification was cancelled in 2005, along with a sufficient amount of the chemical surface layer

81-3-6 which forms on antifouling (AF) formula 121 so that a mottled pattern of the red AF paint is visible interspersed with the green. Extreme caution should be exercised to prevent damage to the paint. A properly cleaned painted surface is described in section 081-2.3.

081-3.3.1.5 All marine fouling shall be removed from surfaces coated with ablative or self-polishing paints so that a bright red or black surface should be present. On subsequent cleanings of ablative and self-polishing paints, a mottled pattern of red and black (representing the second coat of antifouling paint) shall be achieved. Extreme caution shall be exercised to prevent damage to the paint; the paint shall be cleaned with the least aggressive brush necessary to achieve a properly cleaned surface, as described in section 081-2.3.

081-3.3.1.6 All marine fouling shall be removed from painted surfaces treated with a fouling release system. Refer to sec-tion 081-2.1.5 prior to cleaning. Brushes approved for use on fouling release coatings shall be conditioned on a dry concrete surface to remove any sharp bristle tips prior to use. When cleaning, extreme caution shall be exercised to prevent damage to the paint. A properly cleaned painted surface is described in section 081-2.3.

081-3.3.2 CATHODIC PROTECTION SYSTEM CLEANING

CAUTION

The calcareous deposit formed on the dielectric shield shall be preserved.

CAUTION

Cleaning of an impressed current cathodic protection system anode with power tools is prohibited.

CAUTION

Devices (audible or visible) shall be placed in the vicinity of impressed current anodes, reference cells, and dielectric shields to guard these items against damage during the cleaning operation. The location of these items shall be obtained from the ship’s dry docking drawing and ship’s engineer prior to commencing the cleaning operation. The shield area is approximately 16 feet wide by 13 feet high with the anodes located in the geometric center.

081-3.3.2.1 The fouling on a dielectric shield shall be removed as prescribed for cleaning the surrounding hull coating uti-lizing single brush units.

081-3.3.2.2 Fouling on the surfaces of reference cells shall be removed with wooden or plastic hand scrapers.

081-3.3.2.3 Fouling on the surfaces of the impressed current cathodic protection system anode shall be cleaned by hand with either wooden or plastic scrapers and white or green abrasive hand pads. Extreme care shall be exercised to prevent dam-aging the glass reinforced plastic (GRP) holder and the platinum coated wire rod.

081-3.3.2.4 Fouling on sacrificial zinc anodes shall be removed with a wire hand brush, or wooden, plastic or metal hand scraper.

081-3.3.3 PROPULSOR CLEANING

81-3-7

Multi-brush units shall not be used on any propulsor surfaces.

081-3.3.3.1 There are a few different types of propulsors found on US Navy vessels; these include mono-bloc propellers, ducted propulsors, built-up propellers, and controllable-pitch propellers. There are unique components and feature of each type of propulsor; including the hub, blades, tips, edges, palms, bolts, cover plates, bolt on tips, tail cone, cap, Most Aggres-sive Features (MAF’s) and devices. Each requires specific techniques, materials and equipment to effectively and safely per-form the cleaning.

081-3.3.3.2 CLEANING TECHNIQUES. Each surface shall be cleaned by the least aggressive, but effective, tool. Table 081-3-2 provides the approved equipment and material for use on specific propulsor surfaces.

CAUTION

When cleaning submarine propellers, no abrasive power tools or devices shall be used for cleaning the 3-inch area adjacent to the propulsor leading edges, trailing edges, tips, cusps, and fillets (excluding hub to blade interface). Wire brushes shall not be used on the outer 3-inch periphery of any of the propulsor blades. Hand held Scotch-Brite pads (green and maroon), brass, hard plastic or wooden scrapers, nylon, polypropylene and polyester brushes, and authorized high-pressure water jets may be used to clean all areas of all propellers. Extreme care must be taken to retain the proper contour of these critical surfaces. Multi-brush units shall not be used on any of the propeller surfaces.

81-3-8

Table 081-3-2 PROPULSOR CLEANING MATERIALS

Color Size

Disc/ Brush Num-ber (3M

UPC)

Back-up Pad / Holder (3M

UPC)

Blade Faces

Tip (Stan-dard) Fairing Radius

Lead-ing Edge

Trail-ing Edge (with-out knuckle)

Trail-ing Edge (with knuckle)

Hub Fillet Hub

Dunce Cap (Stan-dard)

Blade Palm

CPP

Bolt Covers

CPP

Clo-sure Plate

CPP

End Cover Plate

MAF -

L/E

MAF -

T/E

MAF -

ID/OD

MAF

-Cusps and Fillets

Tips (Bolt

on) Devices

Painted Sur-face

Hand Pads and Brushes

A-1 (Nylon) Black 18 (in) See note 3

N/A x x x x x x x x x x x x x x x x x x x

A-2 (Polypropylene) Red 9, 11, 13 (in)

See note 3

N/A x x x x x x x x x x x x x x x x x x x

C (Flat Wire) Steel 9, 11, 13 (in), (mm)

See note 3

N/A x(5) x(5) x(5) x(5) x(5) x x x

H-1 (Polyester) White 280 (mm)

See note 3

N/A x x x x x x x x x x x x x x x x x x x

H-2 (Polyester) Yellow 280 (mm)

See note 3

N/A x x x x x x x x x x x x x x x x x x x

H-3 (Wire) Stain-less

(mm)

See note 3

N/A x(5) x(5) x(5) x(5) x(5) x x x

D (Silicon Carbide Impregnated Nylon)

Black 5, 7, 12 (in)

See note 3

N/A x x x x x x x x x(6)

Marine Cleaning Disc

D3 extra coarse (silicon carbide)

Black 7.5 (in) 48011- 04417-0

Alumi-num (048011- 04241-1) x x (1) x x x x x x x x(6) x(7)

D5 extra coarse (silicon carbide)

Black 7.5 (in) 48011- 32958

Alumi-num (048011- 04241-1) x x (1) x x x x x x x(6) x(7)

D3 extra coarse (silicon carbide)

Black 9 (in) 48011- 32957-9

Alumi-num (048011- 04242-8) x x (1) x x x x x x x x(6) x(7)

D5 extra coarse (silicon carbide )

Black 9 (in) 48011- 32959-3

Alumi-num (048011- 04242-8) x x (1) x x x x x x x(6) x(7)

Hand Pads

Scotch-BriteTM 33 - Super Fine

White 6x12 (in)

48011- 33012

N/A x x x x x x x x x x x x x x x x x x x

Scotch-BriteTM 7445 - Super Fine (aluminum silicate)

White 6x9 (in)

48011- 16976-7

N/A x x x x x x x x x x x x x x x x x x x

Scotch-BriteTM 96 - Very Fine (aluminum oxide )

Green 6x9 (in)

48011- 08293-1

N/A x x x x x x x x x x x x x x x x x x x

Scotch-BriteTM 86 - Very Fine (aluminum oxide)

Green 6x9 (in)

48011- 05509-6

N/A x x x x x x x x x x x x x x x x x x x

Scotch-BriteTM 7447 - Very Fine (aluminum oxide)

Maroon 6x9 (in)

48011- 04029-5

N/A x x x x x x x x x x x x x x x x x x x

Hand Scrapers

Plastic Various Various Various N/A x x x x x x x x x x x x x x x x x x x (4)

Wood Various Various Various N/A x x x x x x x x x x x x x x x x x x x (4)

Soft metallic Various Various See note 2

N/A x x x x x x x x x x x x x x x x x x

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Table 081-3-2 PROPULSOR CLEANING MATERIALS - Continued

Color Size

Disc/ Brush Num-ber (3M

UPC)

Back-up Pad / Holder (3M

UPC)

Blade Faces

Tip (Stan-dard) Fairing Radius

Lead-ing Edge

Trail-ing Edge (with-out knuckle)

Trail-ing Edge (with knuckle)

Hub Fillet Hub

Dunce Cap (Stan-dard)

Blade Palm

CPP

Bolt Covers

CPP

Clo-sure Plate

CPP

End Cover Plate

MAF -

L/E

MAF -

T/E

MAF -

ID/OD

MAF

-Cusps and Fillets

Tips (Bolt

on) Devices

Painted Sur-face

Water Jet Systems

Water Jet Gun, Non- Cavitating (for painted surfaces)

N/A 2,000 psi

N/A N/A x x x x x x x x x x x x x x x x x x x (4)

Water Jet Gun, Non- Cavitating (for unpainted surfaces)

N/A 10,000 psi

N/A N/A x x x x x x x x x x x x x x x x x x

Notes:

1. For use on trailing edge of surface ships only.

2. All metallic scrappers shall comply with NAVSEA Drawing 245-7605783 VIRGINIA CLASS PROPULSOR SCRAPERS

3. Refer to the Qualified Products List (section 5) for specific equipment and manufactures.

4. Refer to the section 3 for specific operating parameters.

5. Not permitted on submarine propellers

6. Not permitted for use within 3 inches of edges and adjacent surfaces.

7. For use on unrestricted surfaces. Not permited within 3 inches of any unique features.

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081-3.3.3.2.1 For effective cleaning of bare nickel aluminum bronze surfaces of a propulsor with a fouling rating of FR-50 and above, the upper calcareous wall of the barnacles structure is best removed using a scraper, water jet gun, or rotary brush which severs it from the basal plate. The basal plate can then be removed, and the surface cleaned, by using an abrasive disc or brush. For growth that is FR-40 and less effective cleaning can be accomplished in a one-step process using an abrasive brush or disc or abrasive hand held pad. Abrasive brushes and discs must be kept moving across the surface of the propulsor to ensure a clean and smooth surface.

081-3.3.3.2.2 When using abrasive discs, unique configurations of the materials and cleaning techniques shall be used for specific areas being cleaned. Discs shall be mounted to the appropriate disc/brush back-up pad or holder and power unit (refer to Table 081-3-2). When cleaning flat surface (e.g., face) the disc shall be kept flat. When cleaning trailing edges with a knuckle the discs and back-up pad or holder shall be rigid to prevent the disc from rounding the distinct edge, break, knuckle and trailing edge radius. When cleaning convex surface such as the leading edges, tip fairing radius, and trailing edges with a fairing radius (no distinct knuckle or break) the discs shall be flexible (D3) to allow the disc to conform around the curvature. When cleaning concave areas (e.g., fillets) the discs and back-up pad or holder shall be flexible to allow the disc to conform to the geometry. When cleaning the convex areas (e.g., hub, dunce cap, bolt on tips) the disc and back-up pad or holder shall be flexible to allow the disc to conform to the curvature.

081-3.3.3.2.3 When cleaning painted propulsor surfaces hand scrapers, and rotary brushes with nylon, polypropylene and polyester bristle may be used to remove the fouling.

081-3.3.3.2.4 The diver shall maintain positive control of the equipment to prevent water jet guns and rotary tool motors, housings and controls from contacting the propulsors surface. Care must be taken to prevent the quick disconnect fittings on hydraulic hoses, metallic equipment housing and nozzles from contacting the painted and unpainted propulsor surfaces.

Equipment shall be protected with energy absorbing coatings (e.g. rubber) to prevent it from denting or scratching the pro-pulsor surfaces during cleaning.

081-3.3.3.3 EQUIPMENT AND MATERIAL SELECTION Proper tool selection is essential in preventing damage to the surface. Table 081-3-2 provides the approved equipment and material for use on specific propulsor surfaces. Improper clean-ing may result in changes to the propulsor’s acoustic signature, and induce singing or cavitation. The selection of the clean-ing equipment and material is based upon the type of propulsors being cleaned and severity of the fouling. The following precautions must be taken.

081-3.3.3.4 UNPAINTED PROPULSOR

CAUTION

At no time should high-pressure water jets being used on bare propulsor surfaces be allowed to operate at pressures above 10,000 pounds per square inch (psi).

CAUTION

Although approved for limited use on unpainted propulsors, wire brushes shall be used only as a last resort by a highly trained diver to remove severe fouling. Because of its configuration, wire brushes can cause scratches and gouges on the surfaces if used by an inexperienced diver. Wire brushes shall not be used to clean the outer 3-inch periphery of propulsor blades, critical areas and areas of high curvature.

NOTE

Any suspected use of wire brushes or hard tool on the outer 3-inch periphery of propul-sor blades, critical areas and areas of high curvature shall be documented and reported to the Type Commander and NAVSEA Code 00C.

81-3-11

Use only the most experienced personnel when cleaning the outer 3-inch periphery of propulsor blades. These personnel shall be familiar with the critical areas and areas of high curvature geometry.

081-3.3.3.4.1 Surface ship propulsors have a range of complex geometries that will require periodic cleaning. All areas of an unpainted propulsor, except critical areas (the 3-inch area adjacent to the propulsors leading edges, trailing edges), may be cleaned with non-abrasive nylon, polypropylene, and polyester brushes, wire brushes, silicon carbide impregnated nylon brushes, abrasive discs, high-pressure water jet guns, abrasive hand pads, and hand scrapers. The critical areas shall be cleaned by abrasive hand pads, hand scrapers, nylon, polypropylene, and polyester brushes, water jet guns and abrasive discs.

081-3.3.3.4.2 Submarine propulsors have a range of complex geometries that will require periodic cleaning. All areas of an unpainted propulsor, except critical areas (the 3-inch area adjacent to the propulsors leading edges, trailing edges, tips, MAF’s, cusps, fillets and leading and trailing edges), may be cleaned with non-abrasive nylon, polypropylene, and polyes-ter brushes, silicon carbide impregnated nylon brushes, abrasive discs, high-pressure water jet guns, abrasive hand pads, and hand scrapers. The critical areas shall be cleaned by abrasive hand pads, hand scrapers, nylon, polypropylene, and polyes-ter brushes, and water jet guns.

081-3.3.3.5 PAINTED PROPULSORS

CAUTION

At no time should pressure water jets being used on a painted propulsor surfaces be allowed to operate at pressures above 2,000 psi.

CAUTION

Use only the most experienced personnel when cleaning the outer 3-inch periphery of propulsor blades. These personnel shall be familiar with the critical areas and areas of high curvature geometry.

081-3.3.3.5.1 Surface ship propulsors that are painted will require periodic cleaning. All areas of a painted propulsor may be cleaned with non-abrasive nylon, polypropylene, and polyester brushes, water jet guns, and wooden or plastic hand scrapers.

081-3.3.3.6 UNPAINTED PORTION OF A DUCTED PROPULSORS

CAUTION

At no time should high-pressure water jets being used on bare ducted propulsor surfaces be allowed to operate at pressures above 10,000 psi.

CAUTION

Use only the most experienced personnel when cleaning the outer 3-inch periphery of ducted propulsor blades. These personnel shall be familiar with the critical areas and areas of high curvature geometry.

81-3-12

NOTE

Any suspected use of improper cleaning shall be documented and reported to the Type Commander and NAVSEA Code 00C.

081-3.3.3.6.1 The unpainted surfaces of ducted propulsors have a range of complex geometries that will require periodic cleaning. All areas of an unpainted propulsor, except critical areas (the 3-inch area adjacent to the propulsors leading edges, trailing edges, tips, MAF’s, cusps, fillets and leading and trailing edges), may be cleaned with non-abrasive nylon, polypro-pylene, and polyester brushes, silicon carbide impregnated nylon brushes, abrasive discs, high-pressure water jet guns, abra-sive hand pads, and hand scrapers. The critical areas shall be cleaned by abrasive hand pads, hand scrapers, nylon, polypro-pylene, and polyester brushes, and water jet guns.

081-3.3.3.7 PAINTED PORTION OF A DUCTED PROPULSORS

CAUTION

At no time should pressure water jets being used on painted ducted propulsor sur-faces be allowed to operate at pressures above 2,000 psi.

CAUTION

Metallic scrapers are not authorized on painted portions of ducted propulsors

CAUTION

Use only the most experienced personnel when cleaning the outer 3-inch periphery of propulsor blades. These personnel shall be familiar with the critical areas and areas of high curvature geometry.

081-3.3.3.7.1 Ducted propulsors that are painted will require periodic cleaning. All areas of painted propulsors may be cleaned with nonabrasive nylon, polypropylene, and polyester brushes, water jet guns, abrasive hand pads, and hand scrap-ers. Isolated unpainted surfaces found on a painted propulsor shall be cleaned with hand scrappers and abrasive pads work-ing in the direction away from the paint transition.

081-3.3.4 SONAR SYSTEMS CLEANING

CAUTION

Multi-brush units are forbidden on sonar domes or on rubber-coated surfaces. It is not permissible to drive such machines across these surfaces.

CAUTION

Wire brushes are forbidden on rubber or glass reinforced plastic (GRP) sonar domes or rubber-coated surfaces.

81-3-13