The boat is about 200 square feet inside.
We currently heat with an infrared electric heater from Costco. The boat came with a small oil burning heater called a Monitor (similar to the link to give you an idea) and with a diesel Dickinson stove. I took the Monitor out to make room for another bunk. Neither the Monitor nor the Dickinson was hooked up when I purchased the boat. Either would make for a much better heating experience than the electric, but both require a significant amount of work to get going. The Dickinson needs a fuel tank installed and connected to as well as a stack/chimney. Because the roof is not finished on the boat I cannot install the stove pipe. No ventilation means no burning. Dickinsons are very popular on commercial fishing vessels and basically set the standard for marine heat. While they are amazing stoves, I’d love to replace it with a propane stove that would be more easily controlled for cooking instead of being primarily for heat.
UPDATE: Our infrared heater had a little, ahem, issue recently. A little popping sound, a little burning smell… Yeah. So, we were two days without heat in early October. (Note, my youngest son had used a pair of dog nail clippers on the cord of the heater just days after we purchased it. The “fix” didn’t last, causing things to overheat. So, I don’t think it was a problem with the heater, but with a damaged cord.) I had a backup heater, one of those oil-filled radiant type, but the switch was broken. That darn thing was in our way all winter and summer and to find out it was broken was aggravating! Space is such a premium! A friend and former co-worker came to the rescue with a nice Bionaire heater. I had looked at it at Costco and considered it hard. I don’t know how it will do when things get in the teens and single digits, but it’s doing ok in the 30s and 40s! How awesome that I”m saved some cash by a friend’s goodwill!