IIRC our YC has experienced 4 fires on boats in the past 31 years (before that I wasn't a member). One, cause unknown, diesel powered, in a shelter, repaired and back in the club.
Two, electrical, shore power connection at the boat end. Written off, repaired and back in the club
Three, split hydraulic hose on transmission. not too much damage.
Four, mechanic left something behind on a diesel engine, ignition in the wee hours. This could have taken out $millions of neighbouring boats, but a vigilant night guy caught it early. Written off but repaired.
There may be others of less significant circumstances that have not formed part of the dock talk.
Significantly, none attributable to gas power.
I have also witnessed two boats burn to the waterline from galley fires. Both had alcohol stoves.