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Q1. A vessel is to be re-engine and the shafting changed so that a 20 percent higher maximum power is transmitted at a 10 percent reduction in maximum speed. The original shaft was made of steel of UTS 500MN/m² and was solid with a diameter of 450mm. The replacement shaft is to have the same outside diameter as the original but be made of steel of UTS 800MN/m² and be hollow. The original safety coefficient (factor of safety) of eight is to be maintained for the replacement shaft.

Calculate EACH of the following:

(a) The maximum torque that the original shaft can transmit;

(b) The maximum permissible internal diameter of the replacement shaft.