Paul Cooper
Senior Member
My version is the type of crewsaver (hammer i think) that works only with water pressure ie you have to be in water for it to go off. i have had the other version which would go off in the rain or in the back of my car when wet from the walk back from my swim. The other option is to wear an floatation suit, such as sea boat anglers wear. The advantage of these is you will never be cold.