Chapter 3 (Sections 3 & 4)

Question 1

How long can the shaft taper be left exposed?

Answer 1

The shaft taper must never be left exposed for more than three days.

Question 2

How long does a successful propeller change takes?

Answer 2

2 to 3 weeks

Question 3

What is the minimum water depth requirements for a propeller change?

Answer 3

The ship should have a minimum water depth at the stern of at least 10 feet greater than the ship’s draft.

Question 4

What is used to determine when the propeller was last changed and to obtain any available details of the installation.

Answer 4

Docking Reports

Question 5

What must all RFI (Ready For Use) Propellors have with them?

Answer 5

A completed NAVSEA form 9245/1 (usually taped to the propeller in a protective plastic pouch) attached to the propellor.

Question 6

What is SDI and where is it kept?

Answer 6

Ship Drawing Index

Located in the ships log room

Question 7

What is the NSTM and what chapter has to do with propellors?

Answer 7

Naval Ships Technical Manual (NSTM). NSTM Chapter 245, Propellers

Question 8

What is used to indicate the location of propeller lifting fittings and their arrangement on the hull?

Answer 8

Shell Plating Drawings

Question 9

What is used to specify the size of the shaft, amount of taper, and dimensions and fitting details of shaft keys?

Answer 9

Shafting Drawings

Question 10

What is used to specify dimensions, components, materials, and arrangement of the propeller?

Answer 10

Propellor Drawings

(Important information includes: the weight and diameter of the propeller, the size and location of lifting eye plugs, and the size and number of fastening devices (propeller and fairwater cap studs))

Question 11

What can happen if the propellor is rotated while divers are in the water?

Answer 11

Rotating the propeller while divers are in the vicinity may cause serious injury or death. Ensure that the propeller is rotated only at the direction of the dive supervisor.

Question 12

What are the 3 major components of a fairwater system?

Answer 12

1. Propellor Cap (aka: fairwater cap, dunce cap)
2. Cover Plates
3. Rope Guards

Question 13

What are the 3 types of propellors?

Answer 13

1. Solid
2. Built up
3. Controlled Pitch Propellor (CPP)

Question 14

How do you check if the propellor cap is full of fluid?

Answer 14

Jack the shaft until the fill and vent plug is at the 12 o’clock position and then open the plug.

Question 15

What is a major potential problem with the reinstallation of fairwater systems containing Prairie air component?

Answer 15

The fit of the propeller cap onto the replacement propeller seated on the shaft.

Question 16

How much space must the forward face of the propeller hub and the aft face of the strut bearing to leave for a proper welded rope guard removal?

Answer 16

1-1/2 inch overhanging stub from the existing rope guard while still allowing diver access to the propeller gland seal ring studs and nuts

Question 17

How must propellor caps be constructed?

Answer 17

one- or two- piece design

• Ships equipped with Prairie air systems can have two-piece propeller caps with Prairie air system components housed in the forward section.