I cannot help much with technical specifications for rafts or floats that would be available in the event of a warship / destroyer sinking. But I have some information from Manual of Seamanship 1937 (1941 Edition) By Authority of the Lords Commissioners of the Admiralty.
Chapter X1. Life Saving. Page 397 to 401.
Unable to put in Pages 402 to Page 406 at this time (Which have the completion of Methods of Release section as well as sections, Treatment of Apparently Drowned, Resuscitation Drill and Hints to Bathers).
The first 3 Life jacket pictures (out of 4) before page 397 were too much to put in at this time. But they are only to do with the following.
1st Position. Place the Jacket over the head.
2nd Position. Take the tapes attached to the back of the Jacket, one in each hand, in preparation for securing.
3rd Position. Secure tightly between the two lower sections in front of the body.
4th Position is with page 397.
Philip L