Boat ovens are small (I'm speaking of sailboats here). There is no way you are going to roast a turkey in there, even a small one. A turkey breast perhaps, or a chicken would fit. And in fact, most normal bakeware is too big - you have to shop for "mini" versions of cookie sheets, etc.
Boat ovens are gas ovens- a wonderful thing for someone who has had nothing but electric ovens with their high radiant heat loads (burnt on the bottom, raw on top) for decades. And they do heat the cabin. This is a boon in the winter, but it keeps us from doing much with the oven in the summer (we do a *lot* of grilling in the summer). Also, burning that propane and dumping the moisture it produces into the cabin was a problem before we got our dehumidifier. You *will* want to have a dehumidifier if you're planning to use an oven when the cabin is sealed up.
You probably don't think about it, but the stove and oven in your house are *level*. Because of this, your cakes unthinkingly rise evenly across the pan. But boat stoves are gimbaled. Because sailboats heel, the stoves are made to swivel so that the oven is on an even keel even when the boat is not. This would seem to be a blessing, but it is a mixed one. Depending on what is in the oven and on top of the stove, "level" is a relative term. We keep a small bubble level handy nearby so that we can level the stove using the tea pot, etc when the gimble is unlocked. And don't you dare open the oven door when the stove is unlocked and free to pivot, because it will tilt uncontrollably, and spill it's hot contents all over you. Most of the time, we keep the stove/oven locked into place when we are at the dock or at anchor. But when baking that cake, I'll free it and apply weights to level it to get as even a result as I can. The stove is gimbaled in only one plane: to account for the boat heeling. Variations in the fore/aft plane cannot be corrected, other than by moving prodigious quantities of "things" from the aft cabin to the forward cabin, or vice versa. So of course, we don't do that.
There are several marine stoves manufactured out there. Ours is a Seaward Princess. Perhaps its main competitor is the more expensive Force 10. In a major refit, a boat that was near us at the dock upgraded their stove - they chose the Force 10 because, "if it's more expensive, it must be better." It turned out that this is one of the times that the old adage was *not* true. Not only is the Force 10 more expensive, but its oven volume is about half of that in the Princess. Further, the oven is equipped with a totally inadequate burner. It took forever to heat up, and never would reach 400 °F. They eventually pulled it out and replaced it with a Princess. YMMV of course.
Jane just reminded me of another oven incident - we were anchored off of Hope Island, riding out a storm. I baked cornbread - it heated the cabin, made us feel cozy, quelling the storm anxiety, and as a bonus it tasted good too! Cornbread is for me a comfort food. Baking cornbread somehow feeds my soul.
It may be small, but our little oven bakes up a lot of comfort for me.