What a beautifully sad and musical piece of poetry this is, Michael, helped not a little by your chosen form.
Loss seems to be on so many of our minds these twelve months gone, and many of us have good reason, I would imagine. Still, where they have gone, life - with all its hardships and heartache - cannot follow, and the memories they leave behind are forever buoyant and never destined to sink in those metaphorical depths.
I'm not sure commas are needed in the first line of the last stanza apart from the one after 'afloat', but that is personal choice, of course.
This genuinely moved me, Michael. I hope you are well.