perhaps the new hi-tec approach would be to use a drone to either physically dangle a hook on the boat and tow it, or drop a hook and line on the boat so it could be pulled ashore!
I have tried using an airboat to rescue stuff, but the light weight and lack of rudder authority showed it was a no go. Even just towing the traditional cork and string to entangle the mired craft was beyond it as well.
A twin pump boat (no rudder) would probably be the optimum recovery vehicle for weed ?? (keeping a line on it, just in case)
A photographer man with a drone appeared a few weeks ago and took some drone footage. I thought the park was a no fly area but he said no, and produced a map on his phone, and Bushy is is a fly-zone. I think one would have to check the park bylaws though.
Ashley