Engine cooling type pro's and con's

[boathunter]

Air-cooled

Water cooled

Keel cooled

 

I've been coming across these descriptions on my search and need some enlightenment pretty please.

 

Air cooled speaks for itself? I gather these are the older historic type and as such no use for heating water or the boat? Or are they?

 

But Water cooled and Keel cooled? Same thing? subtle differences?

[Athy]

Yes, air-coolled speaks for itself.

Water cooled comes in two flavours:

- Keel cooled - go for it.

- Raw water cooled - avoid.

 

Most modern n/b's have keel cooling. Yoghurt pots usually have raw water cooling because you can't weld the water tank to fibreglass.

[by'eck]

Air and water are generic cooling mediums for engines. If the water coolant is within a closed circuit as is usual rather than using raw canal water, then you have to arrange to take the heat out of it so it can be circulated back to continue cooling the engine.

 

Keel cooling is the most popular method usually via a thin tank welded to the inside of the hull below the water line. It may be located vertically along the side of the swims or horizontally on the base plate. Either way it allows water flowing through it to give up its heat to the cool external surface of the hull.

[steelaway]

Air-cooled

Water cooled

Keel cooled

 

I've been coming across these descriptions on my search and need some enlightenment pretty please.

 

Air cooled speaks for itself? I gather these are the older historic type and as such no use for heating water or the boat? Or are they?

 

But Water cooled and Keel cooled? Same thing? subtle differences?

 

Hi

 

 

Over the last 30+ years the general consensus has been that keel cooling is best.

 

Alex

[boathunter]

Thanks chaps.

Raw water cooled is more outboard engines then.

Air-cooled I guess is something you just put up with (the lack of extra use for the heat) if you want and old thumper? Or are they actually water cooled with an air cooled rad like a car?

[Athy]

Old thumpers come in all three flavours! My Gardner is keel-cooled, Lister SR and similar (very reliable engines I'm told) are usually air-cooled, but some old engines are raw-water cooled.

The drawback of raw water cooling iis that when the water is drawn in it can be accompanied by weeds which block the inlets. So you have to stop the engine and empty the filters to prevent overheating.

[onionbargee]

pipe the engine to a hot tub, get some crack and hookers and have a party !

[PhilR]

Hi

 

 

Over the last 30+ years the general consensus has been that keel cooling is best.

 

Alex

 

Really!

 

I look forward to hearing where you got that consensus from ....................

[boathunter]

Do we need an arguement? Not really I hope.

 

So - back to the air-cooled question - My VW camper is air cooled like a motorbike with a fan chucking loads of air and tinware surrounding the finned barrels and heads.

I can't imagine a thumping diesel engine being like that, so the question remains, are these marine air-cooled engines in fact water cooled with the water being cooled by air via a radiator? Sorry for being thick.

[bizzard]

Do we need an arguement? Not really I hope.

 

So - back to the air-cooled question - My VW camper is air cooled like a motorbike with a fan chucking loads of air and tinware surrounding the finned barrels and heads.

I can't imagine a thumping diesel engine being like that, so the question remains, are these marine air-cooled engines in fact water cooled with the water being cooled by air via a radiator? Sorry for being thick.

They are cooled in a similar manner as your VW camper.

[Alan Saunders]

Old thumpers come in all three flavours! My Gardner is keel-cooled, Lister SR and similar (very reliable engines I'm told) are usually air-cooled, but some old engines are raw-water cooled.

The drawback of raw water cooling iis that when the water is drawn in it can be accompanied by weeds which block the inlets. So you have to stop the engine and empty the filters to prevent overheating.

Yes but a massive Gardner is super silent and the little noise it does make is pleasing to my ear!

 

Alan (3LW)

[LEO]

Hi,

 

Raw water engines are also a pain in the frosty weather, needing to be drained down when not in use.

 

There is also a variation on raw water cooled - closed circuit for the engine and then a raw water heat exchanger which also cools the exhaust, these systems are not too bad and easier to 'winterise'.

 

Water cooled engines are quieter than air cooled and with the former, a useful by-product is hot water supplied by the engine.

 

Some older engines are raw water cooled (Kelvins, some Listers and Nationals) and they don't seem to suffer from too much corrosion which 'sealed' or keeled cooled engines have a chance of resisting by way of the inhibitors incorporated with modern anti-freeze solutions.

 

Keel cooled is probably the best method of cooling the engine, I have tried raw water, converted this to a heat exchanger on one boat and now have keel cooled - even these are not foolproof - if the keel cooling tank is too small, extensive use on a river can lead to over heating problems - modification to overcome this can be expensive.

 

Hope that helps, as stated, I have a keel cooled engine, lots of hot water for domestic use, nice warm engine room, frost protected by anti-freeze, backed up by central heating or electrical heater.

 

L.

[Athy]

Yes but a massive Gardner is super silent

Alan (3LW)

Eh?

You must have forgotten to switch it on.

Mike (2LW).

[Naughty Cal]

Thanks chaps.

Raw water cooled is more outboard engines then.

Air-cooled I guess is something you just put up with (the lack of extra use for the heat) if you want and old thumper? Or are they actually water cooled with an air cooled rad like a car?

 

Not necessarily. Our big Volvo is indirectly raw water cooled (i.e through a heat exchager). It is a very efficient method of cooling the engine, especially as with ours when you need a lot of water to cool it down. Only minor downside is if you get something over the water intake which then starves the system of water and can damage the impellor (water pump). We fitted a speed seal (http://www.speedseal.com/SpeedsealLife/SpeedsealLife.html) to NC earlier this year and it does seem to have done what it says on the tin. In previous years we have used maybe 3 or 4 impellors. This year just 1. Could be luck of course but we suspect not as we have overheated without damage to the rubber impellors.

 

For narrowboats keel cooled systems are favoured but there have been many cases where the keel tanks are not adequately sized. Something to check.

[LEO]

Eh?

You must have forgotten to switch it on.

Mike (2LW).

 

Hi Mike (2LW), Yes and no, the 3LW are smoother sounding than the 2LW, them more cylinders you get the smoother they sound - but all GArdners make sweet music.

 

Mike (2LW - 112 695).

[Athy]

Hi Mike (2LW), Yes and no, the 3LW are smoother sounding than the 2LW, them more cylinders you get the smoother they sound - but all GArdners make sweet music.

 

Mike (2LW - 112 695).

Yes, we moored next to one (well, it was surrounded by about 65 feet of boat) last year and I noticed its smoothness - but silent, nah! To have a silent Gardner would be akin to buying a rare, valuable record and playing it with the volume control set to "0".

Mike (2LW - 105 962).

 

Cor, wotta bunch of trainspotters.....

[OldGoat]

Hi,

 

Raw water engines are also a pain in the frosty weather, needing to be drained down when not in use.

 

There is also a variation on raw water cooled - closed circuit for the engine and then a raw water heat exchanger which also cools the exhaust, these systems are not too bad and easier to 'winterise'.

 

Water cooled engines are quieter than air cooled and with the former, a useful by-product is hot water supplied by the engine.

 

Some older engines are raw water cooled (Kelvins, some Listers and Nationals) and they don't seem to suffer from too much corrosion which 'sealed' or keeled cooled engines have a chance of resisting by way of the inhibitors incorporated with modern anti-freeze solutions.

 

Keel cooled is probably the best method of cooling the engine, I have tried raw water, converted this to a heat exchanger on one boat and now have keel cooled - even these are not foolproof - if the keel cooling tank is too small, extensive use on a river can lead to over heating problems - modification to overcome this can be expensive.

 

Hope that helps, as stated, I have a keel cooled engine, lots of hot water for domestic use, nice warm engine room, frost protected by anti-freeze, backed up by central heating or electrical heater.

 

L.

 

 

Hooray! I'm a fan of "fresh water cooled" engines.

 

The first boats we hired (Teddesley) were all cooled that way and I was impressed how quiet they were and how relatively cool the engine rooms were. So when we decided to build that's what we did.

(OK.OK a hospital silencer is almost as good - but takes up too much space in a trad layout)

 

 

Being cautious by nature I had a keel tank fitted as well - very usful when keeping up with AWBs on the Thames..

Winterising is easy just add some friendly antifreeze through the weed filter.

Having a decent old-schoool builder helped with a ginormous mud box - so we hardly ever get a choked filter.

 

So don't dismiss fresh water cooled engines; the heat exchanger manifold makes a lot of difference. However I do agree that very old raw water cooled and uncooled exhaust manifold engines might be best avoided.

[steelaway]

Really!

 

I look forward to hearing where you got that consensus from ....................

 

 

 

Really

 

I look forward to you convincing me differently

 

Alex

[boathunter]

Really

 

I look forward to you convincing me differently

 

Alex

As Harry Hill would say - there's only one way to fnd out... FIGHT!

 

Seriously chaps, it's great to see such passionate views on the matter. Clearly all types have their fans. I have a love for old VW Campers, but I do know there's no sense to it. They're too small to camp in, the heating is useless, crap mpg, crap performance, over-priced, steering rubbish, brakes inadequate, need constant maintenance and really there's nothing about them that's defensable, but I've had at least one for the last 20 years in spite of that. To me they look cute and sound good and that's enough.

[John V]

Hi Mike (2LW), Yes and no, the 3LW are smoother sounding than the 2LW, them more cylinders you get the smoother they sound - but all GArdners make sweet music.

 

Mike (2LW - 112 695).

 

prefer the 6LX myself

 

Yoghurt pots usually have raw water cooling because you can't weld the water tank to fibreglass.

 

You do it with pipes on the outside

[nebulae]

I took a Lister SR2 out of my boat.It was noisy(air cooled)unreliable and the exhaust through the engine room cabin top tended to cover us in soot and blast brick dust from tunnel roofs.This is the third boat I have had with a Lister(SR2,ST2 and ST3)They have all driven me to distraction.4 years ago I fitted an Isusu from HMI.I was advised by an experienced engineer that retro fitting a keel cooling tank could be tricky.I took his advice and fitted a raw water cooled set up,as used in seagoing boats.The direct cooling is obviously sealed and filled with antifreeze,the raw water exits through the exhaust.This silences the exhaust note as well as cooling the it.The boat has since done 300 hours in widely different conditions with no problems.I have another boat which has been used for the last 40 years in salt water.It has a Volvo Penta MD1 diesel with direct raw water cooling.When I stripped it down recently,I was very surprised at how little corosion there was!

[boathunter]

Ah well, lucky for me I like soot and noise and exhaust fumes. Makes me feel alive.