We are based in the Med near Côte d'Azur, this year for the first time we shall not use the boat much during coldest months from December to February, perhaps just for a few hours sailing every couple of weeks.
Hi Oliver,
Be aware that winter in the north part of the Mediterranean is not always as benign as you might think, indeed some of the coldest weather I’ve ever experienced was in Livorno on the west coast of Italy in the early 1990s. At that time the heating system in the hotel where I was staying could not cope with the low temperature, and neither could the heating system in the shipping agents car.
In order to get warm I had to go out to the shops and stand under the heated warm air curtain at the shop entrance. At night I would turn in fully clothed and with all of the blankets and bedding in the room folded double and pulled around me in order to keep warm. The city utilities were loading sea water into whatever tank vehicles they had and were spraying sea water onto the roads in the hope that it would melt the frozen and compacted snow and ice, though I suspect that it was simply making a bad situation worse.
The point is that you need to watch the temperatures carefully and ensure that your boat is appropriately winterised whenever you are likely to be away from it, and don’t forget to remove the shower head from your deck shower. While your boat remains in the water, it is fairly unlikely that onboard temperatures will drop below that of the sea water, but it’s not guaranteed.
Here in the UK, I’ve fitted pole heaters in way of the calorifier and also in way of the fresh water pump and tank changeover valves, and I keep a daily watch on the weather forecasts. Fortunately I live within a forty minute drive of where the boat is kept over winter, so can react to most weather situations before they become a disaster.