Yes, that kind of design but a marine version. As
@Ianpick capacity to work in wood, maybe in teak or lignum vitae, envisaged with through boring and the weight able to descend on impact, if that is feasible. ALL PATENTS RESERVED!
One of my designs has a hole drilled through top to bottom then crimps and beads to determine the depth.
The problem I had with it is that there has to be a hooklength and bait under the float which tangled with the mainline.
The design below, made of teak, is my solution and does work.
It's not a particularly good picture but the float is made with a vine eye and m16 nut which make up most of the weight, in this case 105g.
There is a leadlink and bait clip attached to the vine eye to which the shockleader is tied. I probably only need the bait clip but they're too small to clip to the eye.
The hooklength is then fixed to the shockleader, crimpbeadswivlebeadcrimp, and using a relay clip goes up and over and back onto the bait clip.
The float then acts as a weight with the bait clipped behind.
The nut and vine eye turn the float over on impact, releasing the hook and whatever length hooklength you've attached.
There will be a way of putting an adjustable clip on the rig to shorten the hooklength and run it off the shockleader.
Not easily visible at distance until I paint them yellow!
Lignum vitae sinks like a stone and is now not really available to buy.