Spoke to a guy today and he said that the auto ones are very easy to go off some even with rain.
Hmmmmm - don't think so.
You'd have to be in a monsoon, immersed in water and already in difficulty for the auto-inflate model to go off.
It is a requirement of most classes of comemrcial fishing vessels these days that they carry self inflating life jackets. On all the inspections I've done I have yet to find a single instance of one going off accidentally...... and the chances are these guys get a damn site more wet than the average angler in the rain.
Apparently they're operated by a block of salt that melts with water (i cant see it myself).
How do they operate?
Although I like Jims 'pixie' idea hugely
to be honest the self inflate function
is indeed operated by a dissolvable tablet built into the activation chamber by the Co2 cannister. But this needs to be completely immersed in water for it to activate, getting wet isn't enough for it to activate.
It is important that if you do get a life jacket with auto-inflate that it is serviced by a dealer annually...... a trivial expense when ones safety is on the line.
Hamish