Heating
Heating efficiently a boat cruising in the Baltic sea requires to have solutions for all seasons and to be ready for the most severe cold conditions. It should therefore reside on a combination of electric and diesel heating, combined with efficient insulation to be able to face all situations.
Electric heaters
When power is available, electric heaters are very convenient. Besides, when wintering the boat in the Baltic sea, heating needs to be maintained to avoid freezing and reduce humidity. Three types of electric heaters can be considered:
Convector heaters
- Less power efficient than fluid inertia heaters
- Faster to heat the cabin, therefore indicated for intermittent use
- Dehumidify the air, which is useful on a boat, particularly when overwintering
- Very light
Fluid inertia heaters
- Reduced electricity consumtion compared to convectors
- Do not reduce humidity
- Clothes/towels can be put on them for drying
- Heavy
Radiating heaters
- Nice homogeneous heating
- Do not reduce humidity
- Through radiating panels or infrared
- Do not need circulation of air for heating
- Can be mounted vertically on bulkheads and ceiling
Cybèle 17
Cybèle 17 is equipped with two electric heaters and a diesel stove (Refleks) with two radiators and a circulation pump.
Power comes from two 230V shore power cables, when we are limited to 10 Amp. One is for the boat connected to a Mastervolt insulation transformer and charger-converter and connects to a little heater with a fan in the front cabin. The second, protected by a circuit breaker, is for a big 2000W heater in the saloon. It is important not to let anywhere in the boat get cold.When only one plug is available, one must look at the Mastervolt in order to avoid high amperage when using an induction plate or a vacuum cleaner.
Belisama
Belisama is equiped with a 2000W convector, a 2000W oil-filled heater, an antartic Dickinson diesel heater and three radiant panels on 220V.
When overwintering, the two electric heaters are maintained at 1000W level, and temperature is checked remotely through a Netatmo weather station installed on board. During sailing season, the heavy oild-filled heater is disembarked, and the radiant panels are used on demand, or the light weight convector if temperatures are really low. During spring and autun sailing, the Dickinson diesel heater is used extensively.
Diesel heater
Diesel heaters are very convenient during winter to heat the boat when living onboard.They are supplied by diesel pumped from the main tank of the boat, either manually or through an electric pump. Diesel flows by gravity in the heater. The heat is very comfortable. Using a diesel heater onboard requires having a carbon monoxide alarm. A small heat generated fan can be put on the stove to increase air circulation and reduce diesel consumption using the Seebeck effect.
Cybèle 17
The diesel Refleks heater on Cybèle 17 is equipped with a circulation pump that feeds two small radiators in the cabins. Maximum consumption is 7l/24h, and the pump draws only 2 amps. There is a way to avoid using the pump, but then the radiators must be mounted higher than the stove. But it was impractical on the Ovni 445. We can also cook on the top of the stove. I have a designated pump to feed the day tank for the stove. Diesel comes from the main diesel tanks.
More on Cybèle 17 Refleks heater...
Belisama
Belisama is equipped with the Antartic Dickinson diesel heater without additional radiators connected. It does not consume any electricity, except for a fan sometimes useful when lighting the heater. For the first 20 minutes of operation, it requires close attention as it takes some time for the a to get established nicely through the aircolumn in the chimney.
Insulation
The floorboards get very cold. I fitted a carpet and cut it to fit around the interior. In some places we have two layers of carpet. And we wear our fur-lined slippers that are very comfortable. I measure the temperatures with a IR laser thermometer. The floorboards are keeping a temperature of 7°C, over the carpet holds 9°C, but the temperature feels much higher!
The access to the cabin used for storage is always closed .
A thermal bridge, also called a cold bridge or heat bridge, is an area in a sailboat which has a significantly higher heat transfer than the surrounding materials resulting in an overall reduction in thermal insulation onboard. All the opening portholes and hatches with a metallic frame are doubled with 4mm plexiglass.
Sometimes it’s very difficult to find the thermal bridge. For example around the chimney, we found that the shipyard forgot to add a piece of thermal insulation .
Other tips
The fully enclosed cockpit tent is very efficient. Keeping the temperatures 5-7°C higher than the outside. It also helps reducing the heat loss from the companionway and from underneath the seats of the cockpit, which are not insulated. In Stockholm we built a second tent over the cockpit to carry the weight of all the snow. We keep the curtains closed from 3 o’clock during winter when it gets dark in Sweden anyway.
An electric blanket (230V 50W) is fitted in the main berth. That allows my wife to go to bed before me. As a true Breton, I don’t suffer from cold!
A water bottle is also very appreciated and doesn't cost a lot!
Between the mattresses and base of the berths, condensation prevention matting keeps the berths both vented and dry.
Some words about snow: it can be useful! Try not to keep all it away, as it insulate the roof. For example the deck fills are sometimes blocked by ice, but not behind the snow!
I think important to avoid humidity as much as possible, with a deshumidifyer (electric or with salt) : it's difficult to have an airflow in winter. We clean the thermal bridges at the junction between roof and deck.