This is an amazing poem I'm a women, therefore I appreciate this very much, your imagery although haunting is truly beautiful. It's almost like watching a scene
You ask for help but I don't think you need much personally. I do though think maybe the end could be a bit more powerful
Example

My secrets held by crabs will be?

Something different from sea and see? Do you see? Anyway this is only what I think but Kudos on a very unique write.

poem Asche. You clearly like it yourself. You say that it is rough but I think not ~ just needs a little work as do all poems when you are editing. Louise Gluck (Nobel Prize last year no less) wrote a poem called 'Confession' therefore I might have thought of another title ~ no problem though if you wish to keep it.

One must be carefull with rhyme it needs to work well, as Teddy has identified in your closing line.  I see that you have paired 'sand' with 'hand' twice throughout.  This sort of says that you can't think of anything better when I know, for sure, that you can.  eg.

Stanza 2.

He wrested me to the ground,
Told me I'd feel mighty fine;
Undressed me without a sound,
Said he owned all that was mine.

Stanza 6 ~ a little hit and miss I think Miss.  Maybe:-

He whispered when the seagulls cried
Short pains throughout my hips and thighs;
And at that moment 'twas when I died
Left drifting on the ocean's guise.   
(You already say that the sea is polluted and the waves are crashing and boundless ~ but just a guise if you are to drift lifeless in it)

Closing line:-
A secret shared 'twixt crab and me. (No 's' on crab)
'twixt very nicely compliments 'twas as used in stanza 6. Don't you think so poet?

I think your piece would benefit from the extra syllable here and there Asche.  Extra syllables are free of charge here on Neo so you may use as many as you like. 

Stanza 3, L4. Add one more syllable:-
And heard discordant sad reply.
(Could be dark reply is it's supposed to be baking sunlight but isn't really bright is it?)

Final stanza add 2 extra syllables, perhaps:-
My empty restless boundless sea.

A little word juggling in stanza 7, line 4 maybe?
By the same sharp shell held in my hand.
Also L2.  To aviod using 'polluted' twice throughout mayhaps trade for 'poisoned'.

Will take another look in a day or two when the tide ebbs.

all that needed to be said has been said in your very powerful poem. An impressive write. Van

Alan has gotten here before me and stolen all the comments and critique that I would have delivered! I am impressed!
I don't think that anyone will object to this staying as it is, on the stream. I feel like this could have been the opening scene in a
movie about a female-serial-killer. I can see where, you and Killer might eventually write something together. ~ Geez.
.

Those stolen moments were a grand larceny, and payback was indeed hell.

I was moved by the experience from a woman's perspective. Rape hits home for me, makes me cringe, having family that have been abused so. the males in a family that have a woman in amongst, that have been violently raped, are scarred by it too. not as much as the woman, I'm sure.

I found the payback ending powerful.

I saw a couple in the Atlantic do
hope it was not you
your poem may not be true
but first prize
they may give to you
most will envy
you

Your atmosphere building is encapsulating!! Love your writing style so much!!