Below freezing for a few hours. Should I worry?

[Steve195]

My boat is on a lift in my covered slip. Weather forecast is for below freezing temps (as low as upper 20's) for 4-5 hours early tomorrow morning and then again Saturday morning. I've already de-winterized and used the boat a couple of times so there's obviously some water in it. Should I worry? I thought about doing the light bulb in the bilge as a quick, easy safeguard.

 

[sdarc]

Don't do the light bulb trick. Not worth the chance. If possible, lower the boat into the water and secure. The water being above freezing will help insulate. Or run the boat in the evening to put heat in. Should take longer then to cool off to freezing levels.

 

[trflgrl]

For extra peace of mind, do both: drop it in the water and run the engine up to full operating temp each evening.

 

[BillK2632]

For peace of mind, drop the boat in the water and run it each evening if you can - but in reality, one or two nights in the mid/upper 20's when the daytime temps are getting above 45deg is not enough to freeze things.

 

[paulswagelock]

Agree with above. Likely not an issue, but if you run it up to operating temperature as late as possible, there will be sufficient heat soak through the night.

 

[Lazy Daze]

We should be saying "a light bulb shouldn't be left in a gasoline bilge". But there have been times when I.... :smt001

I agree that it likely won't be an issue, although it may depend on how warm it gets during the day. Running the engine is good. It also only takes a few minutes to drop the water out of the block/manifold. It won't get 100% of it, but it will definitely help.

 

[magstang1]

After you do whatever preventative method you feel comfortable with, set a bottle of water down in the bilge next to the engine. I bet the next morning it's not even close to frozen.

Would be a simple experiment to give you peace of mind afterward.

 

[JimT]

What is the water temp in your area? We are in the mid 60s. If the water is above 50 you won't have a problem with a few hours in the 20s but I agree that running the engines to temp is a good added precaution.

 

[Steve195]

After you do whatever preventative method you feel comfortable with, set a bottle of water down in the bilge next to the engine. I bet the next morning it's not even close to frozen.

Would be a simple experiment to give you peace of mind afterward.

Good idea, except the boat is about an hour away and I probably won't be able to get up there in the morning. However, I have a battery operated indoor/outdoor thermometer with multiple sensors that records minimum and maximum temps, so I'm going to take it up there later today and put one sensor in the bilge and another on a post in the slip. Then we I go back up there next time I can see what really happened in the bilge vs. the ambient air temp.

 

[Lazy Daze]

When comparing something like bilge temp vs ambient, just keep in mind that it is not a science. There is no hard-n-fast rule to say "if the ambient gets to X temp, then the bilge will drop to Y". There's lot's of variables at play here... What temp did the bilge start at? What temp did the internals of the engine start at? What did the ambient start at? How quickly did it drop? How low did it drop? Ho long did it stay at the lower temp? Was there a wind (which drops the temp faster)?

Use this 'comparison' idea as rough guide... but don't rely on it.

 

[dwna1a]

Water temps at the Richmond Locks are are 52. It's only forecasted to be below freezing tonight/morning. Block your vents and lower her into the water. For extra insurance run her up to temp and then block the vents.

 

[Steve195]

Water temps at the Richmond Locks are are 52. It's only forecasted to be below freezing tonight/morning. Block your vents and lower her into the water. For extra insurance run her up to temp and then block the vents.

My boat is at Lake Anna, which will probably get a bit colder than RVA. Dominion says Lake Anna is at 54 today. I'm going up there around 4pm and will run it, and lower it into the water. I might drop the water out of the block/manifold, too,

Thanks to everybody for their suggestions.

 

[JVM225]

I keep a bottled water in the galley sink every winter when the boat is up on the hard and under shrink wrap. To date, it has never frozen. That includes the two previous winters where we kept getting hit with "the polar vortex".
If you dropped it in the water for extra insurance and peace of mind, you shouldn't have a problem.

 

[Steve195]

Just to close out and report what happened this week to my boat.........

Prior to the cold spell, I dropped my boat on the lift so the outdrive was partially in the water, and the water was just lapping at the keel of the boat.

According to local weather info, Wednesday night the air temp got down to 27 degrees and stayed below freezing for 4 hours. The boat had it's bow and cockpit cover on. The thermometer I left in the helm reported a low 41 and the one in the bilge went to 44.

Last night, the low was 24 and it stayed below freezing for 6 hours. Helm low reported at 36, bilge at 41. The water temp was 54, which obviously kept the boat warm. It's good to know that even with some fairly low temps, I was still well above freezing in the bilge/engine.

 

[Lazy Daze]

Glad to hear everything was A-OK. Just as FYI, though... if you want to take advantage of the warmth from the water, the boat really needs to be IN the water. There was certainly be "some" transfer, but you'll get much more if the hull is fully in contact with the water. Maybe your lift doesn't have a way to securely tie-off the boat if it's in the water - but just a heads up, in case you do.

 

[Steve195]

LazyDaze-
Thanks for the advice. To clarify, my "lapping at the keel" description wasn't really accurate. The boat was probably 6 inches in the water, but not quite enough to float it as it was still resting on the lift bunkers. I did have it tied off just in case, especially since we had 30+ knot winds!