For more than 60 years the D-class has served as the workhorse of the RNLI Inshore Lifeboat (ILB) fleet. The D-class is one of the few RNLI types not to feature a rigid hull. The D-class was specifically designed as a light and highly manoeuvrable rapid response craft, especially suited to close shore work.
There were only 4 Avon S650 boats in service with the RNLI
Design and construction
The D-class lifeboat consists of two sponsons, together housing four inflatable segments intersected by baffles.[2]
This was one of the smaller classes of lifeboat operated by the RNLI, and while there were only 4 Avon S650s in the fleet, the D-class were a common sight at lifeboat stations around the coast. Unlike other members of the ILB fleet, the D-class does not have a rigid hull; all others, with the exception of the Arancia, hovercraft and ALB Tenders, are Rigid Inflatable Boats (RIBs).