RMH on a boat?

I've just had someone ask me if a RMH would work on a boat. I guess it would depend on how big the boat was and how much mass you used, but I've really no idea.

Can someone give me a few pointers?

Well it should and the mass would have to be down low. I am going to be working on a variety for boats but haven't started yet. I do have a design for a boat sized pocket rocket at this time. I think that the boat RMH will have to be a 6 inch system that burns very hot so you could get rid of trash by using it for fuel and get a clean burn. this is an area that i think those little pyrolisis things for making biochar might work really well.
those are a small system that may prove to be a good way to get rid of trash on board if it can handle plastics. so the answer is not yet but i will work on it.

The main issues I see will be:

1) Mass load: must be low and centered; ballast.
2) Air supply - boats can have ventilation problems, absolutely no smoke or CO must be allowed to build up in enclosed spaces. The heater will help mitigate mildew, but the air supply to the compartment where it is located must be worked out well.
3) Water: the logical place to install a mass heater is also the natural location of bilges. Earthen materials might not be suitable, or need to be oiled to the point of becoming linoleum.
4) Firestopping: the hull and bulkheads, and any combustible materials nearby, must be well protected from heat.

Similar in some ways to a basement build.
With the added quirk that your fuel supply may be Gyre trash, sun-dried kelp, and old rope.

Might be worth using hot water as mass, or engine cooling water as thermal source, rather than an earthen mass heater.

We are also thinking about how to do "passive solar" on a boat, especially given that you have reflected cool light (more visible and UV, not quite as much heat) and direct full-spectrum light to work with.
Ventilation would be a great application for passive solar boat design.

-Erica

Ernie Wisner wrote:Well it should and the mass would have to be down low. I am going to be working on a variety for boats but haven't started yet. I do have a design for a boat sized pocket rocket at this time. I think that the boat RMH will have to be a 6 inch system that burns very hot so you could get rid of trash by using it for fuel and get a clean burn. this is an area that i think those little pyrolisis things for making biochar might work really well.
those are a small system that may prove to be a good way to get rid of trash on board if it can handle plastics. so the answer is not yet but i will work on it.

Did you ever get to work on that pocket rocket for the boat?   I am in the process of buying a boat to turn into a sustainable living project and exhibition on alternative living. One of the first things I need to figure out is heating.  I know there are loads of different marine stoves out there but I'm keen to try something that doesn't rely on purchasing fuel.

Did get the design worked out, eventually, but didn't get to try installing it.

If boat shopping, the biggest feature to look for is hull insulation, or the possibility of adding it.  
If your fresh water tanks are isolated from the sea water temperature on the other side of the hull, you have an isolated mass, and lot of options to warm that mass up, whether or not you install additional mass.  (If you have multiple fresh water tanks and can keep some of them cool and algae-and-scale free for drinking, even better.)  

If your living space has only a conductive skin between it and the briny deeps, you are now plugged into the largest thermal mass on Earth.  But Mother Nature controls the thermostat, and laughs at your puny efforts to warm the sea.

Just seen this thread. Some issues immediately spring to mind, but most are covered above.

Obviously your mass needs to be low and centered for balance, but you also need to look at insulating the mass from the hull. Otherwise you will be simply bleeding heat into the surrounding water.