How to Winterize a Saildrive in the Water

[william126]

Hi all,

I leave my boat in the water each winter to get the most out of the fresh air and quiet waterways. In the past I have just ran the engine after each trip and poured antifreeze into the water strainer until I can see it flowing pink out of the exhaust to protect the engine from freezing (full service done each spring).

I now have a new boat with a saildrive though. Has anyone got ideas on how to winterize this while still in the water? My best guess so far is do the same for the engine but remove the hose from the strainer and blow down it until I have air bubbling from beneath the boat so as to force the water from the saildrive unit. It seems a bit unscientific though!

Any ideas woudl be greatly welcomed...

Will

[Pete7]

Will hi and welcome to CF

I see you are in France, but were is the boat? also unless its's obvious is it moored in fresh or salt water?

Peter

[william126]

Hi Peter,

Thanks for the welcome. I've followed this site for the past couple of years as it seems to have a comprehensive answer to almost everything!

Sadly my IT server is in France and I am currently sitting in the UK. My boat is moored on the south coast in Portsmouth, so salt water but flowing enough so that it doesn't freeze. Little bits left in capillaries and small chambers can though...

[Pete7]

Will, we are also moored in Portsmouth, Cold Harbour, Gosport side. The water temperature never goes below 5.c and only once can I remember ice forming on the Solent on 23 Feb 1986 and yes we broke the ice to go diving. However, it was likely this was "freshwater run off" sitting on top of the seawater and the steel pillars from Hyde pier helping it to freeze.

The tidal range of Portsmouth harbour between 4m and 5m each day means the water is well mixed to maintain an average temperature.

http://www.solentforum.org/publicati...hapter%201.pdf

Since the water temperature is always above freezing I wouldn't worry because the temperature of the water will maintain the air temperature around the engine bay and in the leg. If you were lifting out then that would be different. We have a raw water cooled Volvo 2003 and other than an oil change before winter and check the anode just leave it alone.

Pete

[william126]

Thanks for that Pete, and with data backing you up from 1984 I highly impressed! It's true that I may worrying too much as I haven't wintered in Portsmouth yet (I'm up by Fareham lake) and certainly didn't realise the water stayed that warm. It may sound daft but I had never made the distinction between water being in the leg while in the water and on the hard.
To be on the safe side I think I'll still put some antifreeze in the engine should it get really cold, but leave the saildrive alone.
Thanks very much for the advice. Happy winter sailing!
Will

[Pete7]

Since you area on a swinging mooring those greenhouse low watt heaters are out. Checking the engine antifreeze would be a good plan if it is freshwater cooled, especially if you have only just bought the yacht, you don't know what strength the previous owner used.

Nice sheltered spot up their, just make sure you have plenty of ventilation. Although we have a pontoon it doesn't have water or elec so like you rely on ventilation over the winter to combat damp and mildew. We made a mistake sealing up a previous boat, never again

Pete

[Rapanui]

Hi there. We kept a boat in Langstone Harbour for many years and had the benefit of working at the VT yard in Porchester from 1978. It did not happen often but the sea surface at Porchester froze several times in that period. I would guess that Fareham lake would have similar problems as I would expect the sea temperature would get colder the further you are from the harbour entrance. While there is not a vast amount of fresh water entering the harbour, I would think the salinity in Fareham lake would be lower than the entrance and these 2 factors make it more likely to freeze. Might be a good idea to talk to people nearby who should know like Fairweather Marine.

Friends who kept their boats afloat in the top of Chichester harbour overwinter did have problems with sea water circuits freezing and popping core plugs etc. They used antifreeze to protect any fresh water circuits, drained down the calorifier and fresh water tanks and emptied the saltwater circuit as far as possible.

For a saildrive, all I can think of doing is attaching a dinghy air pump to the saltwater pick up line and blowing down to expel water and while blowing shut off the inlet.

The biggest problem will be the above water parts of the circuit as the air temp will get far lower than the sea temp, but there is a risk that water in the saildrive could freeze in a very cold snap. Might be worth investing in GSM boat alarm that can monitor temperature and alarm texts to your phone. They are are about £150 on ebay