What Temp?

[Bad Obsession]

At what temperature, outside, do you have to worry about winterization of your engine? I am not going to mess with my fresh water system yet but I am thinking about starting the engine. I can always re-winterize but at what temperature should I become concerned?

 

[Rob19574]

Well 2 things you need to look at are temperature and time below freezing. If it dips down to 30 degrees for a few hours you should be OK. If it stays there for the better part of a day then you should worry.

 

[Don S/V ILLusion]

is your boat in the water or on the hard? It makes a big difference in that the water will tend to moderate large temp swings around your engine making a short-term hard freeze less likely to cause the ambient temp around the engine to plummet.

short answer - there is no definitive answer.

 

[Tim R.]

Are you on the hard or in the water?

 

[Bad Obsession]

I am in the water. I wouldn't mind getting out for a short sail on a nice day. I have an inboard diesel.

I don't see any days below 32 degrees in the 10 day forecast.

 

[Don S/V ILLusion]

It's always a crap-shoot but you might consider simply draining the raw water side if you don't want to winterize again. It's very simple to do and for short periods, you don't have to worry about rust/corrosion forming inside the block and heat exchanger. Or just watch the weather and put a heater on.

 

[Tim R.]

In the water is much better. The water temp around you will help keep the boat warm(relatively) so check that. No sub-freezing days is also good. A colored boat cover will also help by giving passive solar heat to the boat.

 

[Chris Burti]

You are about 250 mile North of where our boat is docked and that may be climatically significant. However, if you don't need a bubbler, you shouldn't be likely to need anything more than a WM dehumidifier to protect her unless it will be below freezing for more than 48 hours.

I use one because it has a fan to circulate the air and puts out the heat equivalent of a 90 watt bulb. I also have a back up WM heater set to the freeze protection setting and that is all I use for winterising. We don't have nearly enough time to sail and must go when we can. In the winter we will go as long as the air temp is higher than our age (which actually occurs surprisingly often during our eastern NC winters).

On the other hand, you are the one that have to deal with the results of freezing so, if you have any doubts... an ounce of prevention...

 

[Dragonfly6689]

Lot's of factors to consider. How cold and for how long before the cat's water on the patio freezes solid enough to do damage? Low of 25 and the cat's water may have a skim of ice, but not frozen solid.

It also depends on lake water quality and temperature. Recall pure clean deionized water freezes at 32...is sealeave a factor too? The water in Mark Twain Lake is not pure clean or dionized. I think a water quality engineer suggested it froze around 28 degrees.

Also remember the engine is inclosed in a department and located next to the hull which is underwater about 18"-24". The engine would have to cool to below 28 degrees before the water in the heat exchanger would freeze. If the water temperature is 40 degrees, it is going to help protect the engine by helping keep the engine above freezing. The engineers out there can probably calcuate the thermal conductivity and the other variables. My simple mind says that if it's 20 degrees outside and 40 degrees under the hull, then it will take quite a while for the engine to reach the average of the 2 or 30 degrees. Of course, the starting temperature will also affect the outcome.

Now a real time example from Missouri. We sailed this weekend dewinterizing only the engine. It's 70 and cloudy today. Low tonight is to be 23. I'm not worried. High tomorrow is 41 and clear. Low tomorrow night is 18...I'm worried but not too worried. High on Thursday in 39 with a low of 23 Thursday night. High in 50s on Friday. I should be ok.

If the forcast was for 23 tonight and high tomorrow in the low 20's the down to 18 tomorrow night, I'd be on my way to the boat right now.

I have followed this pattern since we bought Dragonfly in 2003 and have not had a problem.

that's my 2 cents worth! Others may have more experience and other thougths.

Mark

 

[Ross]

I keep a 2 quart water jug on the porch railing all winter just to watch the freeze-thaw cycles. It won't freeze solid in less than 24 hours at the low to mid twenties. That is completely exposed. Your engine is sheltered from the cold so the inside of the boat would have to go below 20 degrees for several hours before the engine block would get too cold. That isn't likely to happen again this season.

 

[Steve Dion]

Salt water freezes at a "slightly" lower temp. than fresh water (26-28 deg). I would think that you would not see any damage to your engine unless the temps. stayed below these levels for several days.

If you are on a dock with power, you should be able to place a golden rod or space heater in the area to keep the engine/muffler areas warm enough to prevent any damage.

How cold is the water in your area? I would not think that the water temps. are any where near the ambient air temperatures either.

 

[RAD]

What I use to do when I kept my boat in year round and decided to go for a sail was to open the sea cock and start the engine and go sailing! then when I was done I would close the sea cock and pull the out hose off the sea strainer and insert it into a gallon jug of pink antifreeze and start the engine till it sucked it dry and shut down,then open the drain petcock on the strainer and call it a day, the whole operation would take about 15 minutes and one gallon of antifreeze.