Please read my post!
They are 47ft self righting lifeboats. A design that has been in use around the world since 1851!
A design competition was sponsored by Algernon, Duke of Northumberland, in 1851, with one of the parameters being the “Power of self-righting.”. The eventual result of this competition was the development of the “standard” SR lifeboat of the UK’s Royal National Lifeboat Institution (RNLI).