How cold is ‘cold enough to cause you a problem’

[Red_Duck]

I did quite a bit of searching and my apologies if there is a thread that answers this. I’m going to winterize my 2019 G23 H6 for the first time. The dealer normally does it but the cost is now just crazy (see other thread). I’ve looked for videos on YT and haven’t actually found a great one yet. Any tips on that are welcome.

Anyway, draining the thing appears straightforward but then flushing it with antifreeze is a different level of drama. Hose attachments and fake lakes etc. so my question is, how cold does it have to before you run the risk of a problem?

I live in Georgia. The air temperature doesn’t go below 32 almost ever. The boat is on a lift over the lake which certainly has never frozen so that would add a bit of temperature vs the boat being on a driveway for example.

So ‘dry block’ vs running antifreeze. And of course if the forecast becomes a freak say 20 degrees for a week then I could use a block heater / drop it in the water and run it every day / then go to the trouble of filling it with antifreeze.

I’m in two minds and would welcome members advice..

thanks

[jmo]

Just draining the water the out is the key, backfilling with RV/Marine AF after draining is extra credit. A bilge heater would be plenty sufficient in your case (assuming you don’t lose power), especially if you put the cover on as well. I use a bilge heater in early Spring in Maine since it possible I could get a few days of below 32 degree weather. The rate of heat transfer between 2 bodies is proportional to the temperature differential. So if it’s a few degrees below freezing it will take a long time to freeze the block, if it’s 0 degrees it will freeze 15 times faster.

if in doubt - just drain the the block or use the bilge heater if your skiing year round.

[Red_Duck]

Quote removed by Admin for not following the Guidelines for Quoting Previous Posts in a Thread.

thank you I appreciate your thoughtful response. And the physics, well done

[jpwhit]

I put temperature loggers in my boats last fall to try to answer the question for myself. I put one in our ski club boat that gets used year round and one in a boat at my lake house that sits on a lift above water. The water here in NC never gets anywhere close to freezing. Both boats had covers.

From my tests, the short answer is it has to get really cold for multiple days to have a problem. The biggest surprise looking at the data from the club boat, is that after it had been run, it took almost 3 days for all the latent heat to fully dissipate. When it hadn't been run for 4+ days, and it dropped into the mid 20s for a few nights, inside the engine box never went below 40 degrees.

The boat on the lift sitting above 50+ degree water, stayed even warmer.

Net, it appeared to me that it would take 3-4 days where the high temps stayed below freezing and the low temps were in the teens to cause a problem. Sitting above warm water seemed to give another 10 degrees of buffer.

[Rednucleus]

Our club boat sits on a lift covered with a space heater running. Gets used a few days a week in winter. We have had occasional lake freezes where it does not get run for 1 to 3 weeks. Never a problem and always nice and warm inside when the cover is removed.

[morfoot]

I wouldn't worry about it too much as you're right as it just doesn't get tat cold for too long here in GA. I've got 2 SN on the lift down near BRM and all I do is drain the block, trans cooler, water pump and empty the water inlet bowl on two of the 3 boats ( one is under cover next to the garage). The other one on the lift is always ready to drop and go ig we get a sunny mid 50's day here in GA and I head out for a ski with my neighbors. I've got petcock valves on everything that needs to be drained for when we get below 32'F for more than a day. A bilge heater is plugged in that kicks on automatically when temps hit 38'F. In a pinch you can use an incandescent lightbulb in the engine compartment instead of a heater. We just don't get those multi day below freezing temps like our northern friends. Bottom line is that it's your call and if you go boating in the winter.

[charlesml3]

The rules is "24 for 24." 24 degrees or less for 24 hours straight.

[MN Ryan]

Here in MN, we have 24 for 4, that is, 24 degrees or less for 4 months.

[hal2814]

I personally don’t run marine antifreeze but I also don’t go more than 2 months without running my engine. Air is better at freeze protection than antifreeze is. If it’s cold enough for air to freeze I promise you won’t even be worried about the boat. You’ll have much bigger issues. Antifreeze’s primary function in winterization is rust and corrosion protection. Back during the DFW freeze it got down to single digits and stayed below freezing for days. It was 20F in my garage. I drained everything maybe 2 weeks before the freeze and it was just fine. I’d definitely take draining seriously. That storm we got knocked out power for days. All those “stick a light in the engine compartment” folks were engine shopping that spring. But the antifreeze is overkill for shorter layups. I’m pretty sure the manuals even say the antifreeze is only for extended layups.