Of course, being portable it falls outside the boat safety scheme requirements..which is why I have heard rumours of folk ripping out their built in gas cookers etc on the broads and putting the little portable ones in...thereby not having to construct gas lockers etc into older boats.

Don't you just love the unforeseen effect of regulations.

I've seen cartridge gas heaters on the market for Ł13 or so. I have a portable camping cooker version, and its very good,even though the gas cartridges don't last all that long. On board I have the Origo.

Just use it sensibly and you will be fine. Read The Instructions (as they say.)

Tim