Quadcopter rescue thing.

[single]

Maybe not a bad idea but why carry full life rings and not a simple auto inflation thing?
http://www.nexpected.com/2013/04/lifeguards-in-future-this-iranian-drone.html

 

[Seajet]

Because you know a foam liferaft will work, but there's always a question mark over inflatable jobs you can't test.

Years ago I had a thing like a large grenade which was supposed to inflate when thrown to a MOB; after it being doused in heavy spray quite a lot I and crew decided we didn't trust it, so dropped it over the side in a marina - it sank.