8-line stanzas, rhyming ABACCBDD. Not a fixed meter, but 4 stressed syllables per line in a mix of (usually) iambs and anapests which gives it a certain rhythm. Definitely read it out loud. So perhaps a distant cousin of Ottava Rima.

I was working on a concept of a regular mixed meter, so the first line came - 
                       iamb/anapest/iamb/anapest  - 
with the feel of a rocking boat. But then the poem came out of nowhere, turning melancholy and the rhythm turned to the regular irregularity of the waves on a sea whipped by the wind. I had expected a gentle story of a quiet day on a lake - the poem chose otherwise. Originally line 2 and line 3 were reversed in order, and he was just a bit damp, and with a different, more neutral adverb to describe "dripped". But as the poem turned, I immediately swapped in "relentlessly" to drive the poem into that dark place. I cannot be sure, but I suspect that I was rhyming internally with silently, and "gently" would have been a likely choice. But I think the replacement works even better, the internal syllable rhymes are still there, but less obvious because of the separation: "si-lent-ly", "gent-ly" vs "re-lent-less-ly". To go with a pun, the latter is "less gentle" than the former.