IMHO any boat with a propane system should be required to have a sniffer. I wouldn't feel comfortable on a boat without one. They are easy to install and hook up, and not that expensive. If you have ever seen the videos (sorry, didn't have time to look up a link) of boats blowing up from propane I'm sure you will feel the same way. Propane is probably the most dangerous thing you can have on a boat as it is heavier than air and will build up in the bilge or any low spot, and ignites with the smallest spark. We leave our sniffer circuit breaker on all the time, so that when we first get to the boat and turn the battery switch on the sniffer comes on before we do anything else. It would probably be better to have the sniffer connected to the battery all the time so we don't have to touch the battery switch, still debating the pros and cons of this.
SV Laurie Anne
1988 Brewer 40 Pilothouse