Keeping the engine bay above freezing this winter

[Assassin]

One simple solution is the Eberspacher or Mikuni diesel heaters fitted to commercial vehicles, these have low power consumption on 12 volts and most are thermostatic. One battery will easily run them for a week, so if you have two large capacity batteries you can take one home and slow charge it while the other is on the boat, just swap them weekly.

Look at commercial breakers as they often have these types of diesel heaters or a accident damaged truck from a local transport company who may let you have it from a damaged truck for very little money.

 

[PaulGooch]

One simple solution is the Eberspacher or Mikuni diesel heaters fitted to commercial vehicles, these have low power consumption on 12 volts and most are thermostatic. One battery will easily run them for a week, so if you have two large capacity batteries you can take one home and slow charge it while the other is on the boat, just swap them weekly.

Look at commercial breakers as they often have these types of diesel heaters or a accident damaged truck from a local transport company who may let you have it from a damaged truck for very little money.

Most commercial Ebers will be 24v though.

 

[gjgm]

Don't count on it. A quick google for frost damaged boat engines will soon put you straight.

It's one of those things that you will probably get away with for years and then one particularlt cold snap will catch a few out.

I would take action every year to prevent frost damage whether that is to winterise the engine or add some low level heat. Winterising is a hassle but the cost of a new engine puts it into perspective IMO.

What is it in the engine that is going to freeze, Neale, re seawater?
I ssume not the block as it has a/freeze,usually to -50C. ?

 

[neale]

What is it in the engine that is going to freeze, Neale, re seawater?
I ssume not the block as it has a/freeze,usually to -50C. ?

On a raw water cooled engine the block can and often does freeze. I have heard many tales of cracked blocks due to frost damage. On a fresh water cooled engine the damage would be limited to the heat exchangers assuming the antifreeze mix in the engine is up to strength.

The point I am trying to make is that salt in the water is not a guarantee that it won't freeze, plus many boats that are kept on salt water are possibly kept on water which is more brackish that salt. Think any estuary that has fresh water flowing into it, any locked marina that doesn't get a good flush through and will accumulate rain water reducing the salt content.

A quick google seems to indicate that typical sea water will start to freeze around -2°C, while salt saturated water will freeze at around -21°C. Brackish water will freeze at between 0°C and -2°C depending upon the salt content.

Because the sea itself is a massive body with suitable heat reserve it is rare for it to freeze, but a small amount of salt water in an engine block can easily reach -2°C when the outside temperature drops to -10°C or more like it did last year.

Why take the chance?

 

[rafiki_]

On a raw water cooled engine the block can and often does freeze. I have heard many tales of cracked blocks due to frost damage. On a fresh water cooled engine the damage would be limited to the heat exchangers assuming the antifreeze mix in the engine is up to strength.

The point I am trying to make is that salt in the water is not a guarantee that it won't freeze, plus many boats that are kept on salt water are possibly kept on water which is more brackish that salt. Think any estuary that has fresh water flowing into it, any locked marina that doesn't get a good flush through and will accumulate rain water reducing the salt content.

A quick google seems to indicate that typical sea water will start to freeze around -2°C, while salt saturated water will freeze at around -21°C. Brackish water will freeze at between 0°C and -2°C depending upon the salt content.

Because the sea itself is a massive body with suitable heat reserve it is rare for it to freeze, but a small amount of salt water in an engine block can easily reach -2°C when the outside temperature drops to -10°C or more like it did last year.

Why take the chance?

+1. Even on a fresh water cooled engine, if the raw water side freezes and cracks something, when it thaws, you could have a sinker on your hands. It seriously does happen.

 

[PaulGooch]

+1. Even on a fresh water cooled engine, if the raw water side freezes and cracks something, when it thaws, you could have a sinker on your hands. It seriously does happen.

Always shocks me to hear the people leave sea cocks open when they are no onboard, any time of the year.

 

[rafiki_]

Always shocks me to hear the people leave sea cocks open when they are no onboard, any time of the year.

In our Marina, a couple of sea cocks fractured due to ice, and the boats went down.

 

[neale]

Always shocks me to hear the people leave sea cocks open when they are no onboard, any time of the year.

Not all boats have seacocks. Mine doesn't.

 

[PaulGooch]

Not all boats have seacocks. Mine doesn't.

Be hard to close them then

Wouldn't be very happy with no sea cock on mine, i've got a big hole in the bottom where she sucks sea water in

Guessing yours is on outdrives ?

 

[gjgm]

On a raw water cooled engine the block can and often does freeze. I have heard many tales of cracked blocks due to frost damage. On a fresh water cooled engine the damage would be limited to the heat exchangers assuming the antifreeze mix in the engine is up to strength.

The point I am trying to make is that salt in the water is not a guarantee that it won't freeze, plus many boats that are kept on salt water are possibly kept on water which is more brackish that salt. Think any estuary that has fresh water flowing into it, any locked marina that doesn't get a good flush through and will accumulate rain water reducing the salt content.

A quick google seems to indicate that typical sea water will start to freeze around -2°C, while salt saturated water will freeze at around -21°C. Brackish water will freeze at between 0°C and -2°C depending upon the salt content.

Because the sea itself is a massive body with suitable heat reserve it is rare for it to freeze, but a small amount of salt water in an engine block can easily reach -2°C when the outside temperature drops to -10°C or more like it did last year.

Why take the chance?

I understand the theory;out of interest then, assuming outdrives, how much water is left in the heat exchange when the boat is lifted...I was told it almost all drains out, given the prop/exhaust is 75cm below the exchange?

 

[PaulGooch]

On a raw water cooled engine the block can and often does freeze. I have heard many tales of cracked blocks due to frost damage. On a fresh water cooled engine the damage would be limited to the heat exchangers assuming the antifreeze mix in the engine is up to strength.

The point I am trying to make is that salt in the water is not a guarantee that it won't freeze, plus many boats that are kept on salt water are possibly kept on water which is more brackish that salt. Think any estuary that has fresh water flowing into it, any locked marina that doesn't get a good flush through and will accumulate rain water reducing the salt content.

A quick google seems to indicate that typical sea water will start to freeze around -2°C, while salt saturated water will freeze at around -21°C. Brackish water will freeze at between 0°C and -2°C depending upon the salt content.

Because the sea itself is a massive body with suitable heat reserve it is rare for it to freeze, but a small amount of salt water in an engine block can easily reach -2°C when the outside temperature drops to -10°C or more like it did last year.

Why take the chance?

Ref the highlighted bits above, my boat is nine years old and has spent it's life in :

Cardiff Bay, locked marina and brackish water.

Wisbech Yacht harbour, brackish water, fresh water leading into it and at the mouth of an estuary (The Wash).

Shotley marina Suffolk, another locked marina.

 

[neale]

Paul, I don't really know what your point is. It sounds like you are saying "I have never had a problem therefore it isn't a problem". I would suggest that the engines damaged by frost say otherwise.

 

[Jim@sea]

I would doubt it would get cold enough in the boat to freeze fresh water never mind salt. My boat was in the water through last winter (used regularly), I don't recall the fresh water tank freezing. I have had a boat with no antifreeze in the closed cooling system in the water through the winter in previous years with no problems.

I am a bit paranoid over this issue, only because when I had a Moody 30 (inboard Volvo) after a winter when I came to re-commission the boat the engine block has a big crack down the side.

 

[PaulGooch]

Paul, I don't really know what your point is. It sounds like you are saying "I have never had a problem therefore it isn't a problem". I would suggest that the engines damaged by frost say otherwise.

Nope, i'm saying i've never had a problem. Therefore it's not a problem for everyone.

 

[rafiki_]

Nope, i'm saying i've never had a problem. Therefore it's not a problem for everyone.

Paul, you make your points well, however, I am in Neale's camp on this. I know a Techie who has made a good, if honest living from repairing frost damaged boats. It does happen!! The OP will have to make up his mind about whether he wants to protect the boat, or trust to luck. In my world, I only get one sort of luck, bad!!

 

[PaulGooch]

Paul, you make your points well, however, I am in Neale's camp on this. I know a Techie who has made a good, if honest living from repairing frost damaged boats. It does happen!! The OP will have to make up his mind about whether he wants to protect the boat, or trust to luck. In my world, I only get one sort of luck, bad!!

I fear my points aren't always well made and that's my fault. I wouldn't consider doing anything different with this boat and the use/locations. But if i had a different boat i'd re-access. If i was in fresh water, as you are, i'm sure i'd be doing things differently.

 

[rafiki_]

I fear my points aren't always well made and that's my fault. I wouldn't consider doing anything different with this boat and the use/locations. But if i had a different boat i'd re-access. If i was in fresh water, as you are, i'm sure i'd be doing things differently.

Have you seen the Severn? Fresh?

 

[Sheppy]

Oh dear, and to think I only wanted some advice on keeping the engine bay warm, some very good points though. Clearly there are strong differing opinions over winterisation and I suppose people know what's best for their boats and what works for them depending on their locations.

I don't have the luxury of shore power or the luxury of taking her out over the winter period but I certainly don't want to take any chances of damage. I suppose I could just do nothing and I'd probably be ok but it's the 'probably' I just don't like, so I'll do the usual winterisation work but as far as the raw water heat exchanger is concerned, well, it just seems to make sense to wrap in all up as best as I can, at least that way I know I tried something.

Thanks everyone,
John

 

[longjohnsilver]

Oh dear, and to think I only wanted some advice on keeping the engine bay warm, some very good points though. Clearly there are strong differing opinions over winterisation and I suppose people know what's best for their boats and what works for them depending on their locations.

I don't have the luxury of shore power or the luxury of taking her out over the winter period but I certainly don't want to take any chances of damage. I suppose I could just do nothing and I'd probably be ok but it's the 'probably' I just don't like, so I'll do the usual winterisation work but as far as the raw water heat exchanger is concerned, well, it just seems to make sense to wrap in all up as best as I can, at least that way I know I tried something.

Thanks everyone,
John

Don't worry John, you'll be fine, even better if you use her. Pop over and say hi if you see us on Eos.

 

[Sheppy]

I do see your boat quite a lot and have thought about saying hello, so thanks for the offer. I was out last Saturday and just went up to Dittisham for a little stretch - beautiful day.