Reel on a float

Nice drawing. I think it would take too much away from the buoyancy of the float. It barely has enough to keep the flag up as it is. The added weight of a spool or just the rope on top would roll it over for sure.

Maybe with your current float. But starting with a blank sheet, the float could be slightly longer, or larger in diameter to compensate for the lost material. Of course, I guess a larger float would then have its own drawbacks.

How would you anchor the hooks in the foam?

Haven't figured that one out yet. The hooks don't need to be especially strong just to hold the coiled up rope, but a running fish is something else. The best that I can think of is if the entire recess in the float were a strong plastic box, with the hooks molded as an integral part. Or maybe start with a foam core and coat the whole thing with a fiberglass shell, so that the hollowed out box is an integral part.