GR translation: upended shell cases

[Mike Jing]

V10.20-23, P10.36-39   With a clattering of chairs, upended shell cases,
benches, and ottomans, Pirate’s mob gather at the shores of the great
refectory table, a southern island well across a tropic or two from chill
Corydon Throsp’s mediaeval fantasies, . . .

Here "shell cases" refers to wooden cases used to hold artillery shells, is
that correct?