Yes, Medsailor, a Sardine with a glass door would be the best. But it's out of the question right now, and I'm contemplating a Pet. Comments I've found seem generally positive, but in the absence of published efficiency or BTU info, it's hard to know whether it will put out enough heat, or too much.
Thanks for the reply.
Unless your yacht is really large, it'll put out more heat than you need. I had a cole stove which was not airtight and the molds/patent were bought by dickenson and it is still marketed as their solid fuel stove. It was small (though larger than the pet) and it took my 31' x 10'beam with 6'6" headroom wooden boat from "bloody cold" with snow in the decks to 90degF in no time flat. I lived aboard and used the stove 100-200 days per year for several years and loved it. I did wish it was airtight though.
In fact, I found that wood burned too hot, and too quick and after trying many many different types of fuel, settled on the "duraflame" logs. The 2 or 3 hour logs are made of parrafin wax and sawdust and light easily, burn consistently (which is key) and burn cooler than wood but enough to make my boat 80DegF. I would take a 3hr long and cut it in thirds and each chunk would heat my boat to 80F and each chunk would last 3 hours.
The Pet is airtight, which makes it miles ahead of the stove I had. I think you'll be very happy with it. Personally I never considered the pet though, since the tiny tot is nearly the same size but could hold more fuel and thus would last longer during the night and require less tending.
Wood stoves are marvelous on a boat! I think you'll be happy with the pet. Give the compressed "druaflame" logs a try though, they're great. They can also be stored in damp places (ie a boat) because the wax keeps them waterproof. I used to keep them in the bilge of my sinking wooden boat.