Green’s Dictionary of Slang

bucket afloat n.

also bucket and float
[rhy. sl.]

a coat.

[UK]Hotten Dict. of Modern Sl. etc.
[UK]Sl. Dict.
[UK]Shields Dly News 2 Dec. 2/7: I put on my ‘German flutes’ (boots) and my ‘bucket afloat’ (coat).
[UK]J. Franklyn Dict. of Rhy. Sl. 44/1: bucket and float Coat [...] in the army during the 1914–18 war.