Boats - keeping the engine compartment above freezing
Discussion
So out first cold snap looms; according to the forecast it will be -2 at night soon.
This has brought forward my winterising plans somewhat, but the good news is that I'm able to cadge some shore power. So for a 27' cruiser with a 40hp diesel under the cockpit floor, I'm wondering what power heater I need. I guess the volume of the compartment is 2-3 m3. The bottom can't get colder than zero as it's on water, but 'cold' can and will get in on all other sides, and last year it was -12C.
How about two 120W tube heaters:
http://www.amazon.co.uk/Long-Tubular-Heater-120w-C...
Controlled by this?
http://www.amazon.co.uk/Thermostat-Tubular-Heater-...
I haven't done this before so have no feel for the amount of heat needed.
This has brought forward my winterising plans somewhat, but the good news is that I'm able to cadge some shore power. So for a 27' cruiser with a 40hp diesel under the cockpit floor, I'm wondering what power heater I need. I guess the volume of the compartment is 2-3 m3. The bottom can't get colder than zero as it's on water, but 'cold' can and will get in on all other sides, and last year it was -12C.
How about two 120W tube heaters:
http://www.amazon.co.uk/Long-Tubular-Heater-120w-C...
Controlled by this?
http://www.amazon.co.uk/Thermostat-Tubular-Heater-...
I haven't done this before so have no feel for the amount of heat needed.
TBH I wouldn't bother. I don't know the details of your boat, it's cooling arrangements or whether you want to keep using it over the winter, but as long as your antifreeze is topped up it should be fine. You can always close the seacock and bung some a/f in the top of the strainer if you are worried about the raw water circuit.
Personally, I'd be more worried about a heater malfunctioning and starting a fire!
Personally, I'd be more worried about a heater malfunctioning and starting a fire!
Want to keep the boat usable all year.
The issue is the heat exchanger, where the raw (fresh) water interacts with the coolant circuit. If that freezes and cracks, I get a big bill.
What idiot designs these systems with a freshwater stage?
I don't mind draining the drinking water tanks and winterising the WC, as I can take bottled water and pee in a hedge - but the engine (Yanmar 3JH5E) is important and expensive!
The issue is the heat exchanger, where the raw (fresh) water interacts with the coolant circuit. If that freezes and cracks, I get a big bill.
What idiot designs these systems with a freshwater stage?
I don't mind draining the drinking water tanks and winterising the WC, as I can take bottled water and pee in a hedge - but the engine (Yanmar 3JH5E) is important and expensive!
Simpo Two said:
Want to keep the boat usable all year.
The issue is the heat exchanger, where the raw (fresh) water interacts with the coolant circuit. If that freezes and cracks, I get a big bill.
What idiot designs these systems with a freshwater stage?
I don't mind draining the drinking water tanks and winterising the WC, as I can take bottled water and pee in a hedge - but the engine (Yanmar 3JH5E) is important and expensive!
Trace heating is ideal for that application; it's exactly what it's designed for.The issue is the heat exchanger, where the raw (fresh) water interacts with the coolant circuit. If that freezes and cracks, I get a big bill.
What idiot designs these systems with a freshwater stage?
I don't mind draining the drinking water tanks and winterising the WC, as I can take bottled water and pee in a hedge - but the engine (Yanmar 3JH5E) is important and expensive!
rhinochopig said:
Trace heating is ideal for that application; it's exactly what it's designed for.
OK, do you have any examples/photos of such an installation please? Do you just wrap it round the engine like tinsel round a Christmas tree?Hard-Drive said:
Is the boat kept in fresh or salt water? If salt water, don't worry about it unless the temperature gets truly Siberian. If fresh, just close the seacock and pour some a/f in as I mentioned before.
As stated last time, it's fresh water. I'm aware of the seacock end but I really don't want fresh water freezing in the heat exchanger.This is the engine although I think the heat exchager is not shown:
http://boatdeck.com.au/yanmar-3jh5e/
Those heaters work well. 120W in a sealed compartment makes a notable difference to the amount of condensation on the motors - and therefore they don't spend the winter festering and rusting (aside from the freezing issue). I wouldn't use a thermostat though, I would (have) just leave them on. You'd have to decide for yourself whether 1 or 2 is enough.
Does it have a strainer on the inlet side, above the waterline. If so, I'd also pop the cap off the strainer and fill the pump & exchanger side of it with antifreeze as well. Powercuts do happen.
Does it have a strainer on the inlet side, above the waterline. If so, I'd also pop the cap off the strainer and fill the pump & exchanger side of it with antifreeze as well. Powercuts do happen.
Edited by MattYorke on Monday 22 October 16:26
MattYorke said:
Those heaters work well. 120W in a sealed compartment makes a notable difference to the amount of condensation on the motors - and therefore they don't spend the winter festering and rusting (aside from the freezing issue). I wouldn't use a thermostat though, I would (have) just leave them on. You'd have to decide for yourself whether 1 or 2 is enough.
Hadn't thought of condensation (though my concern is freezing).Did you omit the thermostat because you thought it was just a link in the chain that could fail?
MattYorke said:
Does it have a strainer on the inlet side, above the waterline. If so, I'd also pop the cap off the strainer and fill the pump & exchanger side of it with antifreeze as well. Powercuts do happen.
Well that's called winterising and will take two people and render the boat unusable, which is exactly what I'm trying to avoid.The brief: Go to boat, start engine, use boat, return to base, get off boat, go home.
But can it be done?
Next year the plan is to pull out the entire fresh water side and pay a clever man to retrofit keel cooling. Sorted.
Simpo Two said:
Well that's called winterising and will take two people and render the boat unusable, which is exactly what I'm trying to avoid.
.
.
Don't see why that's a 2 person job? Presumably you turn the seacock off when you leave the boat, it's only another minute or two to pour a/f in the strainer whilst you are in there?
Hard-Drive said:
Don't see why that's a 2 person job? Presumably you turn the seacock off when you leave the boat, it's only another minute or two to pour a/f in the strainer whilst you are in there?
There seems to be a misunderstanding here. Yes I can take the lid off the strainer and pour AF into the seacock (well it's at the bottom of a 2-foot hose) BUT the original suggestion was 'and fill the pump & exchanger side of it with antifreeze as well'. The exchanger is in/on the engine - pouring AF into the strainer isn't going to touch it. To get the AF through the exchanger the engine has to be running while it's is poured into the strainer so the engine sucks it up. So I'd be head-down in the 'engine room' and quite unable to be outside looking under the bathing platform to see when the exhaust water goes blue - the sign that the AF is throughout the engine.Maybe with experience I could guess it but it's my first winter with a new boat.
Here are some photos which hopefully expain:
I'm not an engineer. I beleive the exchanger is the lump on the left top of the engine - I suppose just taking the lid off and chucking AF in is not possible?
Get yourself a de-humidifier that heats too.
Brilliant bit of kit. Put on the gally top with the drain in the sink, leave the engine compartment open, and the whole boat will be dry and toasty.
I have three of them on the go, in garage, house, boat. Don't know how I'd live without them!
I've had a heat exchanger pop the end open with ice before ! (don't ask
) As you say, expensive !
Brilliant bit of kit. Put on the gally top with the drain in the sink, leave the engine compartment open, and the whole boat will be dry and toasty.
I have three of them on the go, in garage, house, boat. Don't know how I'd live without them!
I've had a heat exchanger pop the end open with ice before ! (don't ask
) As you say, expensive !mickrick said:
Get yourself a de-humidifier that heats too.
Brilliant bit of kit. Put on the gally top with the drain in the sink, leave the engine compartment open, and the whole boat will be dry and toasty.
I have three of them on the go, in garage, house, boat. Don't know how I'd live without them!
Well if it's good enough for you I'm interested! Link?Brilliant bit of kit. Put on the gally top with the drain in the sink, leave the engine compartment open, and the whole boat will be dry and toasty.
I have three of them on the go, in garage, house, boat. Don't know how I'd live without them!
Note this an aft cockpit cabin cruiser so the engine compartment is under the cockpit (canvas cover) so one device couldn't do engine and saloon (but I'm not too bothered by the saloon).
I have to pop over to the house tomorrow evening, so I'll make a note of the make and model, as I can't remember off the top of my head.
But not sure how well it would heat under a canvas top in -12 to be honest.
The one I have in the house keeps the chill of 112 sq m though, but it only gets down to 5 degrees here in the winter, albeit very humid.
You can definitely feel the warmth and dryness when you walk in.
I'd definitely have one inside the boat though.
But not sure how well it would heat under a canvas top in -12 to be honest.
The one I have in the house keeps the chill of 112 sq m though, but it only gets down to 5 degrees here in the winter, albeit very humid.
You can definitely feel the warmth and dryness when you walk in.
I'd definitely have one inside the boat though.
mickrick said:
I have to pop over to the house tomorrow evening, so I'll make a note of the make and model, as I can't remember off the top of my head.
But not sure how well it would heat under a canvas top in -12 to be honest.
Indeed, that would be bonkers!But not sure how well it would heat under a canvas top in -12 to be honest.
Priority: Engine compartment (vol 2-3 m3; there are side sections too, connected by cutouts about 2'x6" but I could block them off)
Second: Saloon (est vol 12m3). But even if the saloon is kept above freezing there's a lot of drinking water pipework behind units etc along the side which will freeze whatever.
If this works I'll let you visit and do an honorary bilge clean for me. Can you do French polishing?
Oooh! an invite! At least those bilges are nice and smooth.
The vulgar Taiwan thing I work on wouldn't pass the tissue test
French polishing? Does that involve use of the tongue?
Anyway, have you checked under the back end of that heat exchanger?
You may find a drain cock there. It would be handy if there was, as you could perminently attach a piece of hose to it, to drain the freshwater side down into a container when you leave the boat.
I know some of the Yanmars do, as I once got called out to a Sunseeker Tomohawk (IIRC)that was "sinking" but only when it was running!
Turned out the yard that had winterised it hadn't done them back up before putting it back in the water in the spring.
I'd bet an ordinary lightbulb in that engine space would be enough to keep a frost away.
Talking of heat exchangers and fresh water, are you using magnesium anodes?
Oh, and yes, the lump to the left is the heat exchanger, but taking the lid off and putting anti-freeze in(I prefer to call it coolant, or inhibiter) won't do much, as that's what's in there already.
That's the freshwater/coolant/inhibiter/anti-freeze side.
The river water for want of a better term, runs through the tubes inside of that.
If you do find a drain cock, make sure it's the river water side, and not the anti-freeze side you're draining.
If you do ever add to the anti-freeze, add a 50/50 mix with distilled water, as adding anti-freeze alone will reduce the efficiency of the coolant.
Coolant starts to loose it efficiency when it gets over 50%.
Appologies if you already knew all that!
The vulgar Taiwan thing I work on wouldn't pass the tissue test
French polishing? Does that involve use of the tongue?
Anyway, have you checked under the back end of that heat exchanger?
You may find a drain cock there. It would be handy if there was, as you could perminently attach a piece of hose to it, to drain the freshwater side down into a container when you leave the boat.
I know some of the Yanmars do, as I once got called out to a Sunseeker Tomohawk (IIRC)that was "sinking" but only when it was running!
Turned out the yard that had winterised it hadn't done them back up before putting it back in the water in the spring.
I'd bet an ordinary lightbulb in that engine space would be enough to keep a frost away.
Talking of heat exchangers and fresh water, are you using magnesium anodes?
Oh, and yes, the lump to the left is the heat exchanger, but taking the lid off and putting anti-freeze in(I prefer to call it coolant, or inhibiter) won't do much, as that's what's in there already.
That's the freshwater/coolant/inhibiter/anti-freeze side.
The river water for want of a better term, runs through the tubes inside of that.
If you do find a drain cock, make sure it's the river water side, and not the anti-freeze side you're draining.
If you do ever add to the anti-freeze, add a 50/50 mix with distilled water, as adding anti-freeze alone will reduce the efficiency of the coolant.
Coolant starts to loose it efficiency when it gets over 50%.
Appologies if you already knew all that!
Edited by mickrick on Monday 22 October 20:37
mickrick said:
Anyway, have you checked under the back end of that heat exchanger?
You may find a drain cock there. It would be handy if there was, as you could perminently attach a piece of hose to it, to drain the freshwater side down into a container when you leave the boat.
That would be interesting to know, I'll ask French Marine. You may find a drain cock there. It would be handy if there was, as you could perminently attach a piece of hose to it, to drain the freshwater side down into a container when you leave the boat.
mickrick said:
I'd bet an ordinary lightbulb in that engine space would be enough to keep a frost away.
I wouldn't trust just one not to go pop, but a rack of 60W lamps could do the job and cost a fraction of a fancy heater. If one pops there'd be several left. Can't imagine lightbulbs catching fire either.mickrick said:
Talking of heat exchangers and fresh water, are you using magnesium anodes?
IIRC I asked that question of Mr Shetland (with regard to the thrusters, which have their own anodes) and he said yes. But that does not guaranteee they are... would they have 'Mg' stamped on them?Did I ever mention that I have one of the Detroits start up better than the other in freezing conditions.
Took me a while to work out what was going on having had injector cleans and supercharger rebuilds on both.
The calorifier is obviously heated from one engine when underway but I always leave the immersion on as I am on the boat often enough to just want everything at temperature when I turn up.
So what you say? Well the calorifier being sited as it is below the heat exchanger of the engine circulates the primary water back around the heat exchanger similar to the old heating systems with no pump. Hot water goes up cold water goes down, so taking heat from the calorifier and keeping that engine toasty.
And before you ask, yes I did find out by one of those 'f
k that's hot' moments. 
So there you are, a simple solution to all your problems, simply strip out your hot water system, carefully locate a hole through the hull bottom of a size equal to approx 10mm bigger all round than a propietary calorifier, place calorifier quickly and bung around with mastic sealant and then pipe up to the engine and hot water systems then attach shore supply. You may wish to take the next haul out opportunity to antifoul the protruding lump of calorifier or alternatively upgrade at an early stage to a copper based calorifier thereby obviating the need for antifoul and giving a handy colour match to your copperkote.
HTH.
Took me a while to work out what was going on having had injector cleans and supercharger rebuilds on both.
The calorifier is obviously heated from one engine when underway but I always leave the immersion on as I am on the boat often enough to just want everything at temperature when I turn up.
So what you say? Well the calorifier being sited as it is below the heat exchanger of the engine circulates the primary water back around the heat exchanger similar to the old heating systems with no pump. Hot water goes up cold water goes down, so taking heat from the calorifier and keeping that engine toasty.
And before you ask, yes I did find out by one of those 'f
k that's hot' moments. So there you are, a simple solution to all your problems, simply strip out your hot water system, carefully locate a hole through the hull bottom of a size equal to approx 10mm bigger all round than a propietary calorifier, place calorifier quickly and bung around with mastic sealant and then pipe up to the engine and hot water systems then attach shore supply. You may wish to take the next haul out opportunity to antifoul the protruding lump of calorifier or alternatively upgrade at an early stage to a copper based calorifier thereby obviating the need for antifoul and giving a handy colour match to your copperkote.
HTH.
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