We are proud owners of the Little Cod. It's been our sole source of heat aboard our 45' fiberglass sailboat, as we have wintered over in the northeast 2 years in a row now. As I write, it's morning and it's not even 20 degrees out. Last night it was 10. Our boat is uninsulated and the Cod keeps us up around 70-75 degrees in here without any trouble. You can get up to 80 or 90 degrees in a boat our size if you're willing to part with some extra wood. We also have cooked nearly all our meals on it this winter. Why not? It's free!
Anyway, I was talking with Andrew and mentioned a little trick I have for turning the Cod into an "all nighter" stove. Right now, with very dry wood, I am able to get 6 hours burn time out of a single load of wood. How?
1) Make sure your stove is running... don't do this on your first load, as you probably want a nice bed of coals to keep it going. This trick starves the fire of oxygen.
2) Load up the stove with nice, dry hardwood over a nice bed of coals.
3) "Roar" the stove for a minute or two (damper and vents wide open), making sure all the wood you loaded is burning well.
4) Close the damper and vent completely.
5) The trick! Stuff a piece of aluminum foil into the small crack under the stove door to prevent air from making its way in through the door's permanent vent space. Stuff the foil right in there with a spoon or something to make an airtight seal.
6) Enjoy approx 50% of full output, but enjoy that for 6 hours.
This is what I do each evening before I go to bed. Done this way, the stove will last all night and you won't have to wake up to feed it. Even if you sleep 8 hours or more, you often will find enough embers in the stove in the AM to get things up and running again without kindling.
This method doubles the efficiency of the Cod. Well, I am estimating it halves the output, so that makes sense. :)
A second trick to evaluate how the fire is going without opening the stove:
You can actually feel the fire by putting your hand 6" from the stove surface and moving it around the stove. If you feel heat that is just slightly "too much" for your hand, you have active flames or very hot red coals in that part of the stove. This helps with figuring out how you want to set the vent or load in any additional wood. I mostly use this technique when starting, or just in general to see how the stove is going and if I should change my vent setting mid burn.
I normally do this over the cooktop area and the side of the stove with the vent in it. Moving your hand around, you can feel where the stove is going strongly, or where it needs more air or drier wood.
Through trial and error I have come to something like the all-night trick posted above... I'm not sure what function the little notch under the door serves - it seems to make it so my stove fires too hot and won't shut down even with full damper and adjuster closed - so I filled it in with stove cement. This improved the function of the stove greatly - I could control the burn of the stove more accurately with the air adjuster.
Next I made an artificial gasket for the door. I just put a bead of stove cement around the perimeter, put a layer of newspaper on the wet cement, and then shut the door. This worked great and was pretty darned airtight, but after a while got brittle and flaked off.
Then I tried a bead of cement with a rope of fiberglass stove gasket pressed into the wet cement, then closed the door. This isn't quite as airtight but seems to be holding up better. In either case, you have to be more careful when loading, opening and closing the door, but the burn control is much more accurate. I can shut down the stove when I leave and feel much more secure..., and as is posted above, I can get coals in the morning most days...
Can certainly understand the desire to tweak the stove to achieve longer burn times. However, in order to have the stove pass US EPA & Washington State emission standards, we had to engineer the air to fuel ratio such that the COD would burn clean and pass both certification tests. Which means that the fixed gap under the door is there to allow a clean, low burn rate setting. By reducing airflow, the stove is most likely not burning as efficiently as its original design condition would allow. In situations like these, creosote build-up could become more of an issue due to cooler flue temperatures. So BEWARE by trying to get the stove to function like an airtight woodstove.
An uninsulated boat, heat by little cod. Excellant news! setting up shop in east boston for the same sort of winter. Do you have any suggestions on...hell anything regarding lliveaboard and your experience with the stove etc? Would be great to hear any inights and success stories of your experience.
i have either spoken to or corresponded with many stove manufactures over the past two years or so. i have been looking for a small air tight wood stove around 4-5 kw output, around 20k BTU plus or minus (these are quite common in the UK). by and large they have all told me to pass emissions in US/CA you need to have the small stove run hot. with the air controls featured to quiet the stoves output, as a user would want, would negate the ability to pass EPA particulate emissions. this is also somewhat true of larger stoves. that is all stoves burn most efficiently at at least 80% rated output continuously. therefore it is best for the environment to buy a small stove, and stoke it often. most consumers in the US don't want to do that, and no stove will burn all night like with the air controls opened up like that.
as far as i know the navigator stove works stoves are not air tight models.
a small stove has a harder time keeping the chimney gases hot enough. andrew mentions creosote build up and that will certainly occur if you stove is not hot enough and does not have a large enough bed of coals in it before you dampen it down. a stack themometer is valuable here.
i think it is well known that wood stoves require stoking in the 4-6 hr range. if you want 12 hr burn times you should be burning hard coal. that will do that no trouble at all.