Question

(a) List the variables which affect the force on a rudder. (6)

(b) A triangular bulkhead is 7 m wide at the top and has a vertical depth of 8 m. Calculate the load on the bulkhead and the position of centre of pressure if the bulkhead is flooded with sea water on only side.

(i) to the top edge

(ii) with 4 m head to the top edge. (10)

Answer 1

when a rudder is turned from the centreline plane, to any angle, a force acts on the rudder, given by,

$$F=kAV^2N$$

Where,

k = Constant
A = Area of rudder in m2
V = Ship's speed in m/s

The constant is dependent on size of rudder, rudder angle and density of water.

Variables affecting force on rudder:

Rudder angle
Density of water
Ship speed

These are the three variables, while all other are constant parameters i.e.

Area of rudder
Size of rudder.

✓ Verified Model Answer (Text Solution)

Variables affecting force on rudder: