New question - when to take it out?

[Elessar]

I used to keep a boat on the river Severn at Tewkesbury. One winter we reached -19C, and the surface water in the marina was frozen for 35 days. During this time, several petrol engined boats, with direct cooing of their engines, hence freshwater in the cooling jackets froze up, and on thawing, sank as the water came into the boat via pipes or block.
My boat with twin diesels had indirect cooling, a sealed system like a car engine, with a heat exchanger to cool the coolant. I used 2 off 120W tube heaters to warm the engine room, and this was enough to prevent any damage. I drained down the domestic water system, but had to pressurize the calorifier with a bike pump to get rid of the final 10% of the water. The frozen water surface did no damage to the hull or the outdrives. being a sports boat, the interior volume wasn't too large so I used desiccant to keep the interior dry, and this worked well as I drained it regularly and regenerated.

Every other winter the boat was lifted and chocked for about 5 months. I was much more concerned about freezing as the air temp is always cooler than the water temp. Again the use of tube heaters and draining the domestics kept her fine.

Hope this helps?

Good point re raw water cooled boats.
If it’s raw water cooled you need to take the inlet hose off and suck antifreeze through.
Fitting a Y valve with a cock on it - wired or padlocked shut - makes it easier to get the antifreeze in (so you are more likely to do it).

 

[rafiki_]

Good point re raw water cooled boats.
If it’s raw water cooled you need to take the inlet hose off and suck antifreeze through.
Fitting a Y valve with a cock on it - wired or padlocked shut - makes it easier to get the antifreeze in (so you are more likely to do it).

Hi Mark, it is possible to get antifreeze into the system through the outdrive leg muffs. The challenge is keeping it there, as it drains out, so best bet is to seal the intake/outlet if you can.

 

[Elessar]

Hi Mark, it is possible to get antifreeze into the system through the outdrive leg muffs. The challenge is keeping it there, as it drains out, so best bet is to seal the intake/outlet if you can.

Muffs are still a faff a valve is better for lazy people like me. More likely to happen.
If you’ve replaced the water with antifreeze it doesn’t matter if it drains out.
Nothing there to freeze then.

 

[scottie]

Since being first posted and from its title I have pondered if this post should not be moved to the Vatican forum?