Describe about Thrust Block.

The main thrust block transfers forward and astern propeller thrust to the hull and limits axial movement of the shaft. Some axial clearance to allow formation of an oil film between the collar and thrust pads. This clearance also needed for allow for expansion as parts warm up to operating temperature. Total movement of the thrust shaft (about 1 mm being typical).

 

Michell type thrust pad is good for thrust block. The pivot position of thrust pads may be central or offset.

Central pads are interchangeable in thrust blocks for reversible engine, where direction of load and rotation change. Here two set pads are used. One for ahead side collar and another for astern side collar.

Offset pads for non-reversible engine and controllable pitch propeller (CPP) based engine. Here only one set pad used in thrust collar.