NSTM 81 Flashcards
What dose a relatively hard blister indicate?
Probable failure at the A/C -Steel interface
PDR-50 Blister survived cleanings
What does a PDR-40 indicate?
Excessive cleaning or internal failure of the paint system
Failure of the AC/AF interface results in a softer blister FR-40 (easily broken by cleaning)
What PDR is associated with normal physical wear?
PDR-10 to PDR-30
Due to U/W cleaning action or hydrodynamic effects
What FR is generally observed on the sea chest?
FR-40 First observed over covers and around perimeter of the sea chest grates
FR-50 and above are later observed around and over grates and inner surfaces of the sea chest
Fouling on internal surfaces mist be cleaned by hand held scrapers and water jets
What FR is common on docking blocks areas?
FR-70 and above are common on these surfaces
What is dominant fouling found on props?
Hard fouling, such as barnacles and tube worms
What type of fouling is to be expected on a sonar dome?
What about then there is a failure of the antifouling coating?
FR-10 to FR-30
If Antifouling paint failure should occur FR-50 and above will from
What are the soft fouling ratings?
0- Clean
10- Light
20- Slime
30-Grass
What are the hard fouling ratings?
40 - 100
How do you clean zincs?
With a wire hand brush or wooden, plastic or metal scraper
How do you remove fouling on surfaces of the impressed current cathodic protection system anode?
Cleaned by hand with either wooded or plastic scrapers and white and green abrasive hand pads
What is the keel?
The structure extending fore an aft along the bottom center of the ship and is the principal strength member of the ship
What is a bow truster?
Its a propulsive device that provides transverse trust near the bow of the ship to assist in maneuvering at low speed or in confined waters
What is a masker system?
The masker system consist of belts of perforated plates that run vertically along the hull at the forward bulkhead of the machinery spaces
What types of propellers are there?
Solid
Built-Up
Controlable- Pitch
