November 11th: all these storms have been good for timber delivery!
The boots are only there for scale: this is a stacking storage bin section, cleverly hinged so it folds flat. The wood is nice quality; unfortunately the thing had received such a wallop coming ashore, one of the long pieces was cracked beyond resuscitation.
Very likely to be a spreader, tailor made to cradle a large circular item being carried as deck cargo.