Post World War Two, standard designs were the order of the day.

The 46 ft Watson initially had an aft cockpit with a shelter containing the engine controls.

ON 820 also had the lengthened shelter but retained a flush deck.

Four of the first five boats had two 40 bhp Weyburn CE4 4-cylinder petrol engines, but the fourth, ON 787, was fitted with two 40 bhp Ferry VE4 4-cylinder diesels, making it the first RNLI lifeboat to be built with diesel engines.

In the mid sixties, seven boats were re-engined with 65 bhp Ford-based Parsons Barracuda 6-cylinder diesels after experiments with ON 803 which had been fitted with 47 bhp Parsons Marlin diesels in 1961 and then re-engined with Barracudas in 1963.