I like the rhyme in this poem. It really does give an aura of waves lapping up on the shore...in a somewhat morbid way.

The length of some of your lines throws off the rhythm though. There’s something about this poem that demands structure and you’ve got that for the most part, but the lengthier lines, particularly [Wash me ashore so the sun may reach me] – stretch on a little too far and diminish the power of the rhyme you’d followed through. This line: [But how I long for shallow gladness] is the other one.
My favourite line is the second last one.