Thx @beemer im still missing something in your diagram. Perhaps I’m thinking of another different technique? I’m trying to have one continuous piece of rope in a tub then pay out to the target depth and then clip on to the bow/stern line. A float would be nice in case I need to cut the line and get my setup back later. What confuses me is that your diagram doesn’t show a connection to the bow/stern line from rode in the stern.
Here’s what I was gonna try (sans small float):
Here’s what I was gonna try (sans small float):