Part of the problem was that motor lifeboats were much heavier than pulling and sailing boats, which could be packed with cork to make them buoyant.

Richard Oakley worked out how to use shifting water ballast to create a self-righting motor lifeboat.

The system worked by the lifeboat taking on one and half tons of sea water at launching in to a tank built into the base of the hull.

If the lifeboat then reached a crucial point of capsize the ballast water would transfer through valves to a righting tank built into the port side.

After several years it was found that the calico absorbed water which caused softening of the wood around the copper nails.

In 1962 a prototype boat was built, 48-01 Earl and Countess Howe (ON 968) and in appearance it resembled an extended 42ft Watson-class with a long tapering superstructure running forward from an aft cockpit which was covered, but open to the stern.

In this an enclosed wheelhouse was positioned amidships, accessed by sliding doors on either side at the forward end.

Initially, radio aerials were rigged between the foremast and a bipod mast at the back of the aft cabin, on the roof of which the radar scanner was mounted on a pylon.

Attention now turned to a steel-hulled development of the 48 ft 6 in Oakley which would dispense with the complex water ballast system and achieve its self-righting capability from a watertight superstructure.

Like the smaller boats, the 48 ft 6 in Oakleys were prone to hull deterioration through electrolysis and were not considered for sale for further use.

48-02 James and Catherine MacFarlane after being out in the open at Lands End since 1988, has been sold to a private owner in July 2016 and moved to Berkshire for restoration.