I spotted this little fellow aboard HMS Prince of Wales, presumably a replacement after a few of her boats were destroyed when she engaged the German battleship Bismarck? It has no rear cabin and resembles a 20 ft Fast Tender as in this Vospers add. Comparing the length to that of the Bofors emplacement that is about 25ft long leads to the conclusion this is a 25ft fast motor boat without a rear cabin.
“MIDDIES” OF THE ROYAL NAVY. NOVEMBER 1943, ABOARD HMS CUMBERLAND, AT FLEET ANCHORAGE. LIFE ABOARD FOR THE MIDSHIPMEN OF THE ROYAL NAVY; JUNIOR NAVAL OFFICERS WHO HAVE HAD A COURSE AT A NAVAL COLLEGE AND ARE STILL STUDYING THE THEORY AND PRACTICE OF SEAMANSHIP. © IWM (A 16669)