[spaghetti]

That's an extra safe system IMO.
The only downside is that it must be quite boring for the buddy who stays on the boat: after time he may drop his attention level, and if you rely on him this may turn to Bull S.
Also the ever running engine may disturb or scare the fish, doesn't it?
BTW. Yesterday my ex neighbour, who has a small firm of nautic safety device in my town, showed me his new invention: it's a divers' float with a LED strobe light on the top (and many other interesting features: extensible flagpole, rescue rope folded around like a yo-yo, water proof tank for car keys, cell phone, wallet et cetera).
I'll ask him permission to post some pics on DB (I didn't understand if the patent is already pending or not). I also think he's looking for importers/resellers in foreign countries. I'll let you all DB folks know if there's a business deal available with this.
Cheers.