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Naval Ship Technical Manual Chapter 81 Flashcards

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1
Q

What type of fouling?

Normally slime and grass.

Slime consists of bacteria, fungi, protozoa, Algae; commonly present within a half hour of wetting the surface, can be felt by hand within an hour.

Grass is a form of multicellular Green and brown algae, forms most heavily near the waterline, less evident as depth increases and color changes from green to brown.

A

Softfouling

Slime

Grass and other Soft Fouling

NSTM CH 81 1.2

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2
Q

What type of fouling?

XXXXX appear as translucent weed- or grass-like growths

XXXXXX XXXXX also appear grass-like, but are typically red, brown, orange, pink, or white.

A

Hydroids

Arborescent Bryozoans

Forms of soft fouling*

(NSTM CH 081-1.2.2.1.3)

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3
Q

What type of fouling?

Normally barnacles (acorn) and tube worms (serpulids). Barnacles have conical hard shells with jagged tops. Tube worms form intertwined tubes lying along or projecting out from the hull.

A

Hard fouling

NSTM CH 81 1.2

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4
Q

What type of fouling?

Acorn that is conical hard shells with jagged tops.

A

BARNACLES.
(NSTM CH 081-1.2.2.2.1 )

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5
Q

What type of fouling?

Intertwined tubes lying along or projecting out from the hull.

A

TUBEWORMS

(NSTM CH 081-1.2.2.2.2)

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6
Q

What term?

A result of an active cathodic protection system is deposits of magnesium and calcium carbonate on bare metal surfaces. The bare nickel aluminum bronze surfaces of a propulsor are highly susceptible to a uniform accumulation of deposits. Thickness will depend upon Time from last cleaning and functionality of the cathodic protection system.

A

Calcareous deposits

(NSTM CH 081-1.2.2.2.3)

NSTM CH 81 1.2

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7
Q

What type of fouling?

This type is often found in varying colors. These
organisms are low-profile with minimal extension from the surface of the hull, and often grow in circular patterns
on the hulls of ships.

A

ENCRUSTING BRYOZOANS.

(NSTM CH81-1.2.2.2.4)

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8
Q

What type of fouling?

In advanced stages, mature barnacles and tube worms maybe present along with calcareous bivalve organisms such as musssels or oysters, hydroids with calcareous cellular structure (coral or anemones), and tunicates (sea squirts).

A

Composite fouling

NSTM CH 81 1.2

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9
Q

What does the fouler rating scale consist of?

What does a 0 represent?

Table for Ablative hulls?
Table for fouling release coatings?

A

The 5 most frequently encountered fouling patterns in order of increasing severity.

0 - 4 A rating of 0 represents a clean hull. Ratings increase with increasing variety and severity of fouling.

Table 81-1-1 for ablative hull coatings

Table 81-1-2 for fouling release coatings

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10
Q

What form will divers use to document fouling findings on?

How to divers document results of ship hull inspections for the presence of fouling and the percentage of coverage over various U/W Systems?

A

NAVSEA 4730/3A

Divers May use up to three FRs and Percentages to report fouler findings

*Each component being inspected will have percentages which total 100 percent

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11
Q

Fouling on the propeller can account for as much as?

A

Fouling on the propeller can account for as much as 50% of the increased energy demand associated with a light to moderately fouled hull

(NSTM CH 81 1.3)

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12
Q

How is propulsor surface roughness gauged?

A

Ship Propeller Roughness Gauge
(Rubert Comparator Scale)

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13
Q

What are sonar domes impregnated with or coated with what?

A

Anti-fouling compound

or

they’re surface coated with the hull coating system

*Sonar performance deteriorates rapidly after fouling progresses beyond a FR-3

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14
Q

What is the common form of fouling on docking blocks?

Particular attention to what area should be applied?

A

FR-4

Hull plating, because of their greater susceptibility to corrosion.

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15
Q

After drydock, the rate at which fouling spreads outwards from the docking blocks reflects the effectiveness of what?

A

The anti-fouling paint

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16
Q

What FR is generally first observed over covers and around the perimeter of sea chest grating?

What FR is later observed around and over the gratings as well as on the inner surface of sea chests?

Because inner sea chests are inaccessible to rotary brushes, how should they be cleaned?

A

FR-3

FR-3 & FR-4

Hand-held scrapers and water jets

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17
Q

What is the dominate fouling on masker emitter belts?

A

Hard fouling such as barnacles and tubeworms

*Holes become blocked by calcium deposits or silt ingestion

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18
Q

What can be detrimental to the efficient rotation of the shaft in the water?

GPR coated shafts are normally covered with what?

A

Hard fouling

Antifouling paint
*As time out of drydock increases, paint can wear off exposing the white fiberglass GPR coating

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19
Q

What is the PDR rating scale?

A

Increases in severity, in 10 point increments, from PDR-10 to PDR-100

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20
Q

The first 3 ratings represent what?

A

PDR-10 to PDR-30 represent antifouling painted surface appearances associated with normal physical wear due to underwater cleaning action or hydrodynamic effects.

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21
Q

Why is a rating of PDR-40 significant?

A

Indicates either Excessive Cleaning Actions or Blistering due to Internal Failure of the Paint System.

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22
Q

Failure at the anticorrosive/antifouling interface results in a ____ blister (PDR-__) which is more likely to be broken by cleaning.

A

Softer Blister (PDR-40)

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23
Q

Relatively ____blisters (PDR-__) which have survived cleaning
indicate a probable failure at the anticorrosive/steel interface.

A

Hard Blisters (PDR-50)

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24
Q

Subsequent ratings of PDR-__ to PDR-___indicate
advancing deterioration of the entire anticorrosive/antifouling paint system.

A

PDR-60 to PDR-100

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25
Whenever a rating of PDR-__ or higher is found over a substantial portion of the hull, consult paragraphs 081-2.1.8 and 081-2.1.8.1 before planning any future hull cleaning actions.
PDR-40
26
Delaying full hull cleaning to the point where a significant amount of hard fouling has formed (fouling rating (FR) -3 and above) can result in:
Damage to the coating system.
27
What is a Full Cleaning?
Full cleaning is the removal of fouling from the entire U/W hull.
28
What is a Interim Cleaning?
The term interim cleaning refers to the removal of fouling from propulsors, shafts, struts, rudders and possibly other submerged ship systems (openings & appendages). Approximately 50 percent of the entire fuel savings benefit of cleaning an entire hull (that is, full cleaning) is attributable to the cleaning of propulsors and shafts. *Scheduled between regular full cleanings to take advantage of the significant fuel savings benefits of operating with clean, smooth running gear.
29
What is a Partial Cleaning?
The term partial cleaning refers to any cleaning where only discrete sections of the hull (e.g., forward one-third or forward two-thirds of the hull), appendages (e.g., rudders, sonar dome, fin stabilizers), and systems (e.g., masker air, hull openings) are cleaned. *Time or resources are limited occasionally performed in conjunction with an interim cleaning.
30
What is the difference between cleaning and Grooming?
Cleaning is the term used when actions are performed on a mostly reactive basis at intervals that coincide with ship operations or major maintenance periods to remove noticeable levels of fouling (equal or greater than FR-2), whether it be soft fouling or hard fouling. (Intervals of 3 months or more) Grooming is the term used when actions occurs on a proactive basis, at a very short interval to maintain the hull surfaces in a relatively clean condition. (Intervals of Days, weeks, or a couple of months)
31
Full hull cleanings shall not be accomplished at intervals of less than...?
6 months
32
Cleaning properly applied ablative and self-polishing antifouling coatings should be unnecessary during the first __ to __ months after undocking.
12 to 18 months *Does not apply to unpainted surfaces/ ships should still schedule interim cleanings for running gear.
33
Cleaning of Properly applied fouling release coatings should be unnecessary if the ship operates at the coating design speed .....
Once per month (Coating Design Speed = sufficient speed to shed fouling)
34
What thresholds are used to determine when a Full cleaning should occur? (Ablative and Self-Polishing Antifouling Paints)
FR-4 across at least 10 percent of the hull FR-3 across at least 20 percent of the hull FR-3 and FR-4 summing to cover at least 20 percent of the hull (exclusive of docking block areas and appendages).
35
What thresholds are used to determine when a Full cleaning should occur? (Fouling Release Coating Systems)
The coating is not performing as expected and an inspection yields a: FR-4 with 10 percent coverage or greater FR-3 with 20 percent coverage or greater FR-3 and FR-4 summing to 20 percent coverage or greater Photographic documentation used to record the fouling condition found. If more than 2 cleanings are needed in a year contact NAVSEA 00C in advance for cleaning approval.
36
What thresholds are used to determine when a Interim cleaning should occur?
FR-3 or greater is observed on propeller surfaces, regardless of coverage.
37
What thresholds are used to determine when a Sonar Dome cleaning should occur?
FR-3 or greater is observed over 20 percent of the surface.
38
What thresholds are used to determine when a Masker air systems cleaning should occur?
15 percent blockage is observed on any belt section (that is, waterline to centerline).
39
What thresholds are used to determine when a Propulsion shaft cleaning should occur?
FR-3 or greater is observed over the entire shaft surface (localized fouling concentrations should be spot cleaned).
40
To ensure the greatest payoff for limited cleaning efforts, when time or other resources are limited, the priorities for underwater cleaning are:
a. Propellers b. Forward one-third of the hull c. After two-thirds of the hull.
41
What ship performance indicators may indicate the need for cleaning?
a. A reduction of 1 knot in speed with shaft revolutions per minute (r/min) set for standard speed. b. An increase in excess of 5 percent in fuel required to maintain a specified shaft r/min (such as for standard speed), with propulsion and auxiliary machinery at optimum efficiency. c. An increase in shaft r/min in excess of 5 percent to maintain a given speed.
42
What are performance indicators for steam propelled ships? Ships equipped with main shaft torsion-meters?
Steam- An increase in main turbine first stage shell pressure needed to maintain a given shaft r/min, assuming a constant main condenser vacuum and main steam supply pressure and temperature. Shaft Torsion Meters- An increase in torque at a given shaft r/min may also indicate the need for cleaning.
43
Why should is it imperative that an underwater hull inspection be conducted before initiating any cleaning.
Because of the possibility of other explanations for deterioration in any performance parameter
44
Pre cleaning inspections and Post cleaning inspections should be performed (preferably) by:
The same diving team, immediately following the cleaning evolution.
45
The decision to clean any individual hull which shows signs of a failing paint system requires...
A thorough assessment of that hull's cleaning history.
46
When can an informative assessment of a ship’s underwater hull condition not be made?
If the hull fouling is FR-3 or greater. Not to clean vs. thorough hull inspection Normally the risks associated with cleaning are justified by the need to perform an unobstructed hull inspection. This allows compilation of hull system condition and facilitates intelligent maintenance planning. in areas of significant paint failure in pre or post cleaning inspection, don't clean without TYCOM (Type Commander) approval
47
What are the 2 different systems for hull protection against corrosion deterioration?
Anticorrosive paint system Impressed Current or Sacrificial Anode Cathodic Protection System.
48
What threshold indicates a ship with marginal or failing hull Impressed Current Cathodic Protection Systems? What is needed and conducted for ships when their Cathodic Protection Systems exhibit corrosion above these thresholds?
10% Bare Metal observed on the underwater hull An Electro-Potential Survey UWSH CH 17 "Inspection Procedures"
49
What threshold indicates a ship with marginal or failing hull Sacrificial Anode Systems?
5% Bare Metal observed on the underwater hull or Observation of any inactive anodes
50
What is recommended to prepare and provide a survey plan?
The ships Drydocking drawing
51
What areas should be identified on the survey plan?
a. Pre-clean biofouling conditions of hull, appendages, typical hull openings, and running gear. b. All sonar domes or unpainted surfaces (particularly propellers and masker belts). c. All protruding appendages (e.g., bilge keels, fin stabilizers, auxiliary and secondary propulsion units). d. Running gear (e.g., rudders, struts, bearing housings, fairwaters and rope guards, and shafts). e. Cathodic protection systems; zincs, impressed current anodes, references cells, and dielectric shields. f. Junctions of hull surface with struts, skeg, stern tubes, sonar dome, and other appendages. g. Keel block and side block areas from last drydocking. h. Sea chests, ballast tanks, and hull openings. i. Previously identified damaged areas.
52
Does black and white video allow accurate evaluation of paint condition or the quality of the cleaning?
No To adequately assess cleaning effectiveness, damage, and paint condition, a high-resolution COLOR VIDEO SYSTEM is required.
53
If video recording what should the recording include? What shall the recording include?
Ship name Hull number Location or component on the hull Date A scale and color reference indicator to assist in the analysis of the video transmission.
54
How are photographs identified? What is included in the photographic view?
Ship name or Hull number Location or component on the ship Date A size scale and color reference shall be used in each photographic view.
55
What is a desirable amount of current to clean in? What current shall be avoided, unless dictated by operational necessity?
.5 kts - carries the debris away from the worksite 2 kts - Avoid
56
Ablative and self-polishing antifouling paints, when properly cleaned with the least aggressive equipment to remove all biofouling, should have a ___ ___ ___ .
Bright Red Surface Cleaning should not result in scratches or swirl marks on the surfaces of abrasion of edges, corners, seams, welds, or rivet or bolt heads that expose or extend into the underlying layer of coating.
57
When cleaning a hull when should NAVSEA 00C be contacted?
When the ship's intermediate Antifouling layer is removed. (red, black, red) The first red layer and the black layer would be gone leaving it on the last layer of red AF paint.
58
When did non-ablative vinyl antifouling paint no longer become specified for use on navy ships?
2005
59
What type of AF paint generates a layer of Cuprous Oxide that is a green chemically insoluble layer on the surface that will become harder to remove as the paint system ages.
Non-ablative vinyl antifouling paint *Ablative and Self polishing antifouling paints do not generate a green chemical layer of cuprous oxide.
60
What is the underlaying layer for fouling release coatings? What is the least aggressive method to remove bio-fouling? When do you suspend cleaning?
Typically Pink, Light Gray, or White Water Jets If coating is peeling or flaking or is scratched or gouged by the cleaning document and contact NAVSEA 00C
61
What should follow the cleaning of propulsor surfaces?
Propulsor polishing to remove any remaining basal plates, all calcium deposits, and produce a smooth finish (Rubert Scale B or better) Ships with PRAIRIE system exterior emitter holes shall be free of fouling
62
what is acceptable post cleaning test for Ships outfitted with PRAIRIE system?
The first five emitter holes at the hub and the last five emitter holes at the tip shall be clear, no two adjacent holes may be blocked, and no more than two holes in any series of 10 shall be blocked, and the maximum number of blocked holes shall not exceed 5 percent of the total number of holes.
63
When cleaning painted propulsors what criteria shall they meet?
The same criteria as the hull coating.
64
When cleaning ducted propulsors what criteria shall they meet?
The painted portion shall meet the hull coating criteria. The unpainted portion shall be polished following the cleaning to remove any remaining basal plates, all calcium deposits, and produce a smooth finish (Rubert Scale B or better).
65
When cleaning water jet propulsors what criteria shall they meet?
Painted surface of inlet ducts and water jet components shall meet the hull coating criteria. Unpainted hydraulic components ((linkages, cylinders, hoses, and cables) shall be free of fouling. Unpainted surface of the water jet propulsor shall be polished following the cleaning process to remove any remaining barnacle or oyster basal plates and all calcium deposits in order to produce a smooth finish (Rubert Scale B or better).
66
What is the purpose for a cleaned propulsion shaft surface? What is the criteria for a cleaned propulsion shaft surface?
To remove all biofouling, produce a smooth surface, and facilitate inspection of the shaft for any indications of damage (i.e., fiberglass disbondment, cracks in the coating, and possible corrosion and pitting of the underlying metal shaft). The cleaned shaft will be red in color (for ablative antifouling paints) or red to mottled red (for non-ablative vinyl antifouling paints). A clean fiberglass shaft with no remaining paint will be white in color.
67
Typically, what are sea chests painted in? When cleaning a sea chest what shall be free of any biofouling? After cleaning, why do sea chest coating systems appear more worn than the surrounding hull coating?
The same coating system as the adjacent hull. Exterior hull, fairing surface, surfaces of the sea chest grates, screens or splitter bars, and the internal walls; that are within the reach of the diver and the employed tools. Due to the increase water flow and geometry of the grates, screens, and splitter bars fouling is often greater than on the surrounding hull.
68
What kind of preparation must be made prior to hull cleaning? How far off the pier? How much depth beneath the keel?
Ship shall be breasted out a minimum of 4ft from the pier and clear on the outboard side. Aircraft carriers shall be breasted out a minimum of 20ft Minimum of 6ft at mean low water All ships in the vicinity will be notified and the ship and any adjacent ships shall be properly tagged out for diving including CAPACS
69
Is the use of barnacle buster, coach bolt brushes, or similar devices authorized?
NO
70
How do you determine the type of antifouling coating on a ship's hull?
Consult the latest Docking Report to determine the type of Antifouling Coating on a ship's hull.
71
Do you clean the Calcareous deposit formed on the dielectric shields?
No, they shall be preserved.
72
Should you clean impressed current cathodic protection system anode?
No, not required. Cleaning could result in damage to the surface and affect performance. *clean after contacting NAVSEA 00C
73
When a hull has significant fouling and requires cleaning how do divers clean the cathodic protection system?
Divers shall search, identify, and mark the location of each anode and document its condition, then hand clean the area surrounding each anode to a 1-foot diameter outward, taking care not to clean the anode surface prior to operating any multi-brush vehicle in its vicinity.
74
**How is cleaning removed on sacrificial zinc anodes?**
Wire hand brush or a wooden, plastic, or metal hand scrapper.
75
Can multi-brush units be used to clean propulsor surfaces?
No, they cannot be used to clean any propulsor surface.
76
What are all the different types of propulsors found on U.S. Navy vessels?
Mono-Block Propellers Ducted Propulsors Built-up Propellers Controllable-Pitch Propellers
77
Unpainted prop- Where should wire brushes and hard tool not be used to clean on a propulsor's blades? Can you use a high-pressure water jet?
The outer 3-inch area adjacent to the propulsor's leading edges, trailing edges, tips, MAFs, cusps, fillets, and leading and trailing edges. not at pressures above 10,000psi
78
Can you use a multi brush unit to clean a sonar dome or on rubber-coated surfaces? Wire brush? High pressure water jet?
No, they are forbidden
79
How are sea chests cleaned?
Hand scrapers, single brush units fitted with nylon, polypropylene, or polyester brush or water jets. When using high-pressure water jets to clean sea chests and gratings, do not allow jet stream to contact painted hull surfaces adjacent to sea chests.
80
How are wood and fiberglass hull coatings cleaned? How is hard calcareous fouling removed?
With Single brush units operating with nylon, polypropylene or polyester brushes and multi-brush units operating with brush composed of nylon, polypropylene or polyester, wire or a combination of these materials. Using handheld scrapers.
81
How is FIBERGLASS (GRP) COVERED PROPULSION SHAFTS cleaned?
With single brush units up to FR-3 and wire brushes to remove any fouling of a higher rating *use caution with a wire brush to not damage the GRP
82
How are AUXILLARY PROPULSION UNITS AND SECONDARY PROPULSION MOTORS Cleaned? (Z-Drive?)
The painted fairing plate and motor housing shall be cleaned as prescribed for the surrounding hull coating. The propeller shall be cleaned with wooden and brass scrapers, green, maroon, or black abrasive hand pads, 3-inch diameter black coating removal discs, blue surface conditioning discs, and water jets. The support column shall not be cleaned.
83
How is the inlet to the bow thruster cleaned? How is the bow thruster prop cleaned?
The inlet to the bow thruster, grates and bars, and inside surfaces shall be cleaned as prescribed for the surrounding hull coating. The propeller shall be cleaned with wooden and brass scrapers, green, maroon, or black abrasive hand pads, 3-inch diameter black coating removal discs, blue surface conditioning discs, and water jets.
84
How is new equipment utilized for U/W hull cleaning approved for use? What documentation is submitted to NAVSEA 00C?
Thru testing and documentation submitted to NAVSEA 00C for approval. Documentation shall include a copy of the approved test plan, equipment description and specifications, operating parameters, results, observations, and conclusions.

DV SWE (23 decks)

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