"Jeff Morris" wrote in
The third approach is to reduce the odds of the vessel sinking, with
positive floatation
and/or collision bulkheads. Multihulls have an advantage
This didn't help the racing multi "Bullfrog Sunblock". Sailing from Auckland
New Zealand to Australia it hit a submerged object ,thought to be a shipping
container . It tore out the center hull and sank like a stone.Luckily the
crew was out on deck at the time and survived if the had been in their
bunks who knows.

I have read about "forward looking sonar" , it'd be a hell of a drain on the
batteries to have it on all the time.

Neil C