I really like this, and will continue to think on it, but Im thinking there is nothing to add.
The only thing is, maybe, a couple of "translation by microphone" items.
"A legend goes forth This a message in a bottle" (this message in a bottle? Or: a message in a bottle? Or: this, a message in a bottle? -- if it is like it's typed, that's okay, too -- just verifying. )
"Yet very now and then, -- every?"

Cool. I changed my original manuscript once I realised you were spot on. It comes of writing at night when my mind is active and full of creative energy but also manic and less clear on grammatical or spelling items...

Cool.

I like this poem :) (My interpretation at least) is that its about how we are constantly sailing and searching for meaning and hope i life, in the ceaseless, unebbing waves, that break, bend and toil. Demons assail our thoughts when all the time the sailors (us) never realise true peace at home..

Or is it a Christian allegory?

I wrote a rhymed poem a while back with similar themes, but arrived with very different conclusions:

http://reformingthehereticalmind.blogspot.sg/2015/03/sometimes-i-wonderwhich-of-those-ideas.html