Davy Jone's Locker

Davy is a bastardization of Duffy, the West Indian term for ghost. Jones comes from Jonah, the prophet who spent a few uncomfortable days lodged in the GI tract of a whale. And a locker, loosely defined, is a place to store valuable things. So the phrase "He's gone to Davy Jones' locker" (i.e., he cashed it in) loosely translates as "He's safe with Duffy Jonah now."