I'm puzzled by another expression in Desolation Island and also in Fortune of War, and maybe in other of this author's books.

It comes up when there has been an action at sea, and the expression is, "He lost the number of his mess." Note, "the number", not "a number", which I would understand to mean that some indeterminate number of his messmates were killed in the action.

But "lost the number of his mess?   And not just in one sentence, in one book, but the same phraseology several times in the course of just two books?

Can someone enlighten me?

Dave Oesterreich