Inexpensive cabin heat while under way?

[David Sanner]

If you just want to use it motoring the engine driven hot water heater works great.  Pumps out the heat and drys out the cabin and even warms up the cockpit near the companionway.
https://c34.org/wiki/index.php?title=Cabin_Heater
Also works nicely on occasion running the motor on the hook to charge the batteries a bit and make some hot water / dry the cabin out.

I'm not sure about using my portable diesel heater in any kind of serious wind/waves but I think it would be fine on the side deck conditions permitting.
I just put mine on the side deck just outside and open hatch with a short stub of ducking but I imagine it could be secured closer to the mast and with a longer duct pump warm/dry air into the cabin underway in moderate conditions w/o serious spray.
https://c34.org/wiki/index.php?title=Diesel_Cabin_Heater_-_Portable

As far as the chinese made heater's safety I feel a whole lot better about using it than my tent propane heater.  Of course I used a carbon monoxide monitor for either.  Also the diesel heater pumps out the heat... my tent heater did knock off the chill but you had to be close to it ... and again, doesn't dry things out like the other heaters.  As mentioned on the wiki page I update the fuel line to get a cleaner burn and it's been trouble free since then.  All of the "shoe box" diesel heaters are pretty complex so can have issues (mainly glow plug & atomizing screen) but outside of that they perform really well.  Here's a fun guy who cruises N. of the Artic circle - does a comparison of different types of diesel heat (eg Refleck) - https://www.youtube.com/watch?v=qV3KsQe7VPI

[Rick Roberts]

Works great and fairly easy to install beside the diesel tank tap.

Rick, any photos/description of the install?  How were exhaust and ducting lines run?

I will be back at the boat in a few weeks in Mexico and I could take some photos then. The heater is installed in the cockpit locker, the piping runs thru the floor of the cockpit locker. From the head, once you remove the the square toilet paper cabinet. You have easy access from there. From that point there's a "Y" splitter, one end runs to the aft cabin, the other runs in between the hull and the liner of the head "cabin". Then from the Nav locker, there's another splitter. One end runs to the bottom of the Nav locker and the other one runs all the way to the V-berth thru the small compartments where your back rest on the Port side settee.