There are hundreds of heaters out there that could fit my yacht and probably do a great job.


However, I have had two diesel-electric blowers – none of them worked satisfactory. That is, they worked fine as long as they worked. But after a few years they both started to have starting problems, black exhaust, noise and vibration and consuming batteries. The last part is a serious problem during winter and long cold nights. It is hard for our normal summer-batteries to hold up with the extra consumption during winter. The nights are longer and colder, so you tend to use more time in the cabin – consuming more electricity. Sooner or later you end up worrying about charging your batteries instead of sailing and enjoying the scenery. You know you are over the limit when you start looking for an excuse to start the engine.

The last diesel-electric blower died rather slowly of rust. I spent hours servicing it. But it still leaked exhaust into the hot-air and letting the monoxide built up in the cabin. If I had fallen asleep in the fumes, it would highly probably be the start of a very long nap.

  • First – When choosing a new heat-source I decided it should be simple. My experience is that anything that can go wrong in a boat sooner or later will. And I will end up servicing it a nice day while fair winds are outside of the marina.
  • Second – I wanted a heat source that runs without electricity – remember: when you need your heat most, electricity will be scarce.
  • Third – It had to look like it belonged in my cabin and be sturdy enough to keep going in rough weather.


Danish Refleks has been making diesel-heaters since the early 1900’s. They are fitted in most small danish commercial fish-boats going into the North Sea and the Skagerrak summer or winter. They are known to faithfully heat the cabin no matter whats going on outside – as long as they are given diesel. I can’t think of any better recommendation. Besides – I love it when the installation brochure makes sure you understand that there will be a slight diesel-drip in 10 meter (30 feet) waves – no more than 1/2 litre in 10 hours, and there is an overflow outlet that runs into a small holding tank. I mean, if Refleks worries about the heat in 30 feet waves, it is more than enough for me… Besides they recommend you to clean the oven after it has burned for a few months. First – burning for months? – second the cleaning is dropping a tablet of some sort into the oven and keep going… I like the attitude.

Nothing is as simple as it looks in the brochure. My cabin-floor is tilted so I needed to make a fitting I could bolt to the bulkhead. Then the space is really limited – I really need to be able to pass between the oven and the table even when “Salt” is listing hard to port. And it should be possible to do that without burning your bum or frying a Helly Hansen. And I had to make a heat-shield between the heater and the bed. It is a good idea to have the oven as low as possible in the boat. It sucks in cold and damp air from the bottom and let it out dry and hot from the flanges at top. So if you want the damp and cold out, the oven should be as low as possible.


I bought the smallest and simplest oven called 66M from Refleks. In fact I bought it at the old-fashioned industrial building of Refleks in Ringe outside Odense in Denmark. The fabric is something else. It is placed in the middle of a meadow and looks like an old whisky distillery in Scotland. Inside everything is made by hand and assembled in long lines. As I visited them a Friday in august they had all gone home. But among the trees in the yeard a lady showed up, called another and soon I had my oven, complete with exhaust-pipe, deck flange, and caps. They even put it together particularly for me.


The stainless steel fittings was made by a local blacksmith from my drawings. It is made of two parts – one bolted to the bulkhead and supporting the oven (the oven only weights 7 kilos), while functioning as a try for accidental oil-drips and one part protecting the bed. Besides the hassle of making holes in stainless steel, it was a breeze to fit it all.

With the help of my big brother Morten we cut a hole in the roof/deck with a hole-saw and fitted the deck-flange loosely. Then we wrangled with the exhaust-pipe. I need it to angle away from the passage, make a huge u-turn and back up at the roof. It all fitted together, and when thighting the flange the cosntruction turned rigid.

A standard 8mm diesel-hose was fitted to the main diesel tank and taken underneath and behind everything until it crawls out of a small hole cut in the floor underneath the oven. A second hose is coming from the overflow outlet at the regulator and put into a small holding tank – in my case a two liter water bottle with the hose through the cap and taped securely. I have no plans of keep the oven going in 10 meter waves!

The diesel hose from the main tank is connected through a cut-off walve from Refleks. This will cut of in event of overheating. And the feeding dieselhose is fitted with a filter to ensure that filth from the tank is stopped before it hits the regulator.

Gale tested

So far the oven has been burning for 3 weeks without any incident. It is burning at an absolute minimum and still heats and dries out the boat even though it has been raining and blowing a gale continuously this november.

The Kaskelot depiction takes you topside