Hi Andrew, thanks a bunch for the thoughts. My first guess was the stove pipe, too, but I wasn't sure. This model has a collar that measures around 3.5" ID and just under 4" OD. I'd thought the pipe was supposed to fit inside the collar, not over, so there's my first big mistake--I'd used the 3.5" measurement to go from.
Even a half inch in diameter is a fairly large percentage of the total area of the pipe when we're dealing with flow, isn't it?
At the stove collar is the only place where one switches "the rule" about pipe ABOVE going down INTO the pipe below. It is usually so hot there that creosote would not dare drizzle out. The reduced pipe size will have an effect but you also likely have other issues going. Overall you just need to confirm with a piece of incense (smoke source) that you don't have a negative pressure or flow of air out of the boat when the wind blows. When this happens all your chimney is doing is supplying "make up air" to the cabin and overriding the hot updraft. This checking can be done w/o the stove running and if you have flow out the stove, you will need to adjust things to stop the inrush of air down the chimney.
Well intended, fine mesh spark screens can also clog quickly and kill flow. Your thick, long, uninsulated pipe on deck might prove to be a great creosote condenser. You might have to insulate that portion to stop it from doing that in very cold weather. Study your flow to see where things are working in reverse is your main task though to start. A/NSW
Thanks a bunch. I ripped out my thick-walled pipe and ran 4" pipe throughout... the stove's running a ton better, and I got rid of about 50 lbs of weight on board. I'm also playing with the indoor/outdoor pressure discrepancies, and that's helping.
Last question (maybe): does the stove pipe hat make much difference as far as draft goes? It seems that a good one would make a difference, but I've heard conflicting reports.
