jujubee

You miss out. Fill my moat with your tears!

Davy Jones' Locker Why sailors should have given the name Davy Jones to "the fiend that presides over all the evil spirits of the deep" (Smollett) is not clear. Some philologists, nothing that Black West Indians refer to ghosts as duppies, suggest that "Davy Jones" may derive from "Duppy Jonah"--Jonah's ghost. Certainly sailors long used "Jonah" to mean anyone (or anything) that, like the original Jonah, was thought to mean bad luck aboard ship--which was why Jonah was flung overboard to be swallowed by the whale. However Davy Jones acquired his name, his locker is the ocean bottom, the final resting place of sunken ships, drowned sailors and anything else given the deep six.

Deep six, the.Though this phrase sometimes means the grave, it doesn't, as you might think, refer to a deep "six by three" hole in the ground; it's from the sea, not the land. When a ship moved toward shallow water, the crew would take soundings with a lead weight attached to a line. The line was marked at specific intervals, as with a knot, a piece of calico, a strip of leather and so on. The marks were placed at one fathom (six feet or 1.83 meters), two fathoms, five fathoms and ten fathoms. If the line ran out to one of the marks, the leadsman would call out "Mark five!" or whatever the depth was; for depths between the marks, he'd estimate and call out "Deep four!" or "Deep six!"
But--why do we say "deep six" rather than one of the other "deeps"? I'd guess it had to do with the tides, whose rise and fall almost anywhere in the world is less--usually much less--than six fathoms. That is, something or someone thrown overboard in six fathoms at high tide would remain submerged even at extreme low water; if you give something the deep six, you've disposed of it permanently.

Between the devil and the deep seaThe "devil" in question was the outermost seam of the deck of a wooden ship. If you're between the devil and the deep sea, you're in imminent danger of going overboard--though the modern sense is closer to "between a rock and a hard place."