engine cooling

[Trix]

I have found an engine that would suit my boat but it is raw water cooled, the boat appears to already have an intake for the water, however ive been told that weed is a problem on the canals and to avoid raw cooling. So can I either fit a filter inline(or out side for that matter) to catch the weed or would this need emptying to much or can I fit a skin tank and use the engine or is that a different system all together.

 

Is raw water cooling used at all by anyone???

[steamraiser2]

I have found an engine that would suit my boat but it is raw water cooled, the boat appears to already have an intake for the water, however ive been told that weed is a problem on the canals and to avoid raw cooling. So can I either fit a filter inline(or out side for that matter) to catch the weed or would this need emptying to much or can I fit a skin tank and use the engine or is that a different system all together.

 

Is raw water cooling used at all by anyone???

 

 

A few use raw water cooling. I wouldn't recommend it though because weed is a big problem..as is freezing during the winter months. With a skin tank you never need to worry about weed and can properly antifreeze the engine. Get a tank!

[Trix]

A few use raw water cooling. I wouldn't recommend it though because weed is a big problem..as is freezing during the winter months. With a skin tank you never need to worry about weed and can properly antifreeze the engine. Get a tank!

 

but can an engine designed for raw cooling be used with a tank I can t think of a reason why not unless the water pumps are different???

[GUMPY]

but can an engine designed for raw cooling be used with a tank I can t think of a reason why not unless the water pumps are different???

 

Most engines now do not use raw water cooling

The two on the barge here use indirect raw water cooling not the same thing at all.

 

What is the engine and does it have a heat exchanger if not there is a good chance that you could just connect it straight to a skin tank.

[casper ghost]

Does the engine have a wet exhaust as that would need changing to 'dry exhaust' if it had. Alot of boats still have raw water cooling, not something i'd recomend fitting myself.

Casp'

[Trix]

The engine is a yanmar ysm 8 the owner said I would need to fit a water trap on the exhaust so maybe that means it has a wet exhaust, whatever that is

[Iain_S]

Gamebird (26' Sea Otter) is indirect raw water cooled, with a wet exhaust. There is a Vetus filter on the raw water intake, and we have only had problems once, when we used the boat's shallow draft to cross a bund, before our local canal was officially opened. (We therefore claim to be the first non BW boat to cruise from Linlithgow to Falkirk. BW didn't let us down the wheel, though )

 

Weed isn't a problem; we get a few small bits in the filter, but most of the weed that is likely to cause a problem is floating, and the intakes are far enough away from the surface to prevent ingress. There are a couple of other local boats with similar systems. They, with slightly deeper draught than us, had a few problems in the early days when the water depth was only a couple of feet, or less, but their systems seem to have been reliable since.

 

My winter precautions consist of draining the exhaust and the impellor pump. There is another method, which consists of pouring half a litre or so of anti-freeze mix into the filter with the engine running, but I don't do this for environmental reasons

 

If you already have a skin fitting for a water intake, and don't have a skin tank, raw water cooling is, IMO, the way to go, although, IMO again, indrect s better than direct, as you aren't puting silt through anything apart from the heat exchanger and exhaust which are easily cleaned.

 

Iain

[Mac of Cygnet]

Like Gamebird, Cygnet is indirect raw water cooled, with a heat exchanger in the engine and a Vetus strainer. Contrary to what people say, weed has never been a problem, and the strainer rarely needs cleaning (literally a 1-minute job). However, I have no filter on the water intake at hull level, and occasionally an object such as a twig or such may get trapped in the intake narrowest point (the seacock), which entails a simple removal of a hose (ten minute job, twice last year). You can easily tell when this has happened, as much less water comes out of the exhaust, and the engine note changes long before overheating occurs.

 

HOWEVER, the biggest problem I've had is grit wearing the bearings of the raw water pump - I blame the Huddersfield Narrow Canal! Resulting in it leaking of water into the bilge. But as long as 90% of the water is cooling the engine, I'm not too bothered abut that.

 

As regards winterising, I use the addition of antifreeze method, which Ian doesn't like for environmental reasons (it goes into the canal/river when you start the engine again), but the dilution is so enormous that I simply can't believe it does any harm.

 

The big advantage of raw water cooling is on rivers, where inadequate skin tanks can overheat on long runs, as I have experienced on a previous boat. This is not a problem with raw water cooling, except when blocked - see above. If you plan to restrict yourself to canals, a skin tank is probably better, but I certainly wouldn't convert from a raw water system if already installed. You get used to them.

 

Mac

[Trix]

Ok so if I have the inlet which I think is there I can use the raw system if I use a heat exchanger would that mean I have to have two pumps? one to pump the water around the engine and one to pump the water through the heat exchanger thanks for the replies so far.

[PhilR]

Ok so if I have the inlet which I think is there I can use the raw system if I use a heat exchanger would that mean I have to have two pumps? one to pump the water around the engine and one to pump the water through the heat exchanger thanks for the replies so far.

 

Yes, you will need two pumps.

 

I have owned boats with raw water cooling and raw water/heat exchanger cooling. A heat exchanger has several advantages:

 

1. You will have clean coolant with a rust inhibiting anti freeze solution circulating around the engine.

2. The engine will (should) incorporate a thermostat to give optimum operating temperature (most raw water engines run too cool causing inefficiencies and more risk of bore glazing)

3. If the inlet strainer gets blocked you will have plenty of warning before any engine damage is likely.

4. It is possible to fit a water cooled silencer rather than a bulky traditional silencer. which will need lagging.

 

There used to be several companies which sold marinising parts for automotive/industrial engines, including heat exchangers pumps etc etc.

You should find a few on a Google search and maybe useful info too.

[RobinJ]

but can an engine designed for raw cooling be used with a tank I can t think of a reason why not unless the water pumps are different???

Yes, generally marinised engines have a heat exchanger anyway, if its indirect and you decide against any sort of raw water, simply remove the shell and tube and change the end caps.

I converted mine to raw water, indirect, in order to keep the gearbox cool, rather than the engine, but it works well. On those rare occasions in shallow water, when there is a problem with stuff getting sucked up, the primary system justs carries on! The hull fitting has a coarse strainer, if anything does go over it, simply blow down the pipe! The strainer sifts out all the small stuff, and if the water is bad I might have to clean it more than once a day!

[Mac of Cygnet]

The strainer sifts out all the small stuff, and if the water is bad I might have to clean it more than once a day!

 

I would regard that as a real nuisance. My Vetus strainer, which is bucket-shaped, and not next to the hull but inline after the seacock, has a large surface area and hardly ever needs cleaning out. I've done it twice this year, including Yorkshire to Sharpness and halfway back - about 300 hours of boating.

[Naughty Cal]

As others above ours is indirect raw water cooled. The benefit being there is no skin tank to fit and large amounts of water can be used to cool the engine. Our boat wouldnt be big enough for an adequate sized skin tank to be fitted.

 

The main issue we have is plastic bags blocking the water intake. The rubber impellor which pumps the raw water is water lubricated so if it is starved of water even for a short time it warps and becomes less effective at pumping water. These impellors are sacraficial carrying spares is a must really.

 

I would regard that as a real nuisance. My Vetus strainer, which is bucket-shaped, and not next to the hull but inline after the seacock, has a large surface area and hardly ever needs cleaning out. I've done it twice this year, including Yorkshire to Sharpness and halfway back - about 300 hours of boating.

 

Sounds like you may have a coarser (larger) hole size on your strainer. We have to do ours once a month or so to keep it clean, that could be because the tidal Trent and Humber are very silty though and tends to block up the holes in ours fairly quickly.

[RobinJ]

I would regard that as a real nuisance. My Vetus strainer, which is bucket-shaped, and not next to the hull but inline after the seacock, has a large surface area and hardly ever needs cleaning out. I've done it twice this year, including Yorkshire to Sharpness and halfway back - about 300 hours of boating.

I think there has only ever been once when there was no water at all!

It is quite good as the bits of weed etc., tend to get pushed up the strainer to the top, so looks worse than it actually is.

[twbm]

Nuneaton has a heat exchanger on the engine cooled by canal water drawn through a flat sieve on the hull side. It's not so bad at the moment, having been thouroughly cleaned out in dock last December, but when the holes start to fill up with rust and other detritus it needs cleaning with a long handled brush two or three times a day. A skin tank will avoid all that plus the other advanatges of not freezing etc. etc.

[Trix]

Appears there are supporters of all types, can anyone answer (simple yes or no will do explanation would be nice though) is an engine that is raw cooled different to one that is not ie pump or can you just connect the inlet and out let to the skin tank and fit a different exhaust, I think I have read it right that raw water engines cool the exhaust as well.

 

The boat is equipped to take raw cooling and the engine is raw cooled however it would not be difficult at this stage (boat out being welded) to add a skin tank during the engine installation.

That is the decision that I have to make assuming the engine does not sell before I make it.

Hope that makes sense.

[RLWP]

Perhaps if you told us what make of engine you have found we could answer that definitively

 

Richard

[Tony Brooks]

The engine is a yanmar ysm 8 the owner said I would need to fit a water trap on the exhaust so maybe that means it has a wet exhaust, whatever that is

 

 

I suspect this is an 8hp yacht engine and probably direct raw water cooled - single brass water pump.

 

I can see no reason why taking the bottom skin tank connection to the water pump inlet and then re-routing the water that normally goes into the exhaust system into the top of the skin tank via T (more later) should not work. The engine is producing the same heat for a given load & speed however it is cooled.

 

Fit the T into the run from engine to top of tank at the highest point and run an upward running pipe from the T to an expansion bottle/tank sourced from a scrap car (bung the extra connections up with corks in short stubs of hose.

 

Connect up the dry exhaust to the now dry mixing elbow and blank off the raw water inlet on the elbow.

 

I am 98% certain this will be just fine.

 

 

If it is indirect raw water (heat exchanger) cooled it is relatively easy to convert to tank cooling as long as the heat exchanger/manifold is used as the fresh water header tank.

 

Remove the impeller in the raw water pump and all the small pipes & hoses associated with it. Plug the two holes where this system connects to the heat exchanger/manifold. One will be obvious and the other will be the one that runs to the exhaust mixing elbow.

 

Remove the larger hose that runs from the manifold to the engine water pump (the one driven by the alternator belt). Take a large hose form the bottom of the skin tank to the engine water pump inlet. Connect the manifold connection to the skin tank.

 

In all case try to avoid upward and downward loops in the pipes and ideally they will both run uphill to the engine.

 

Once again I am 98% certain this will be fine although the cold engine may have no water left in the header tank because of the large volume and contraction as it cools.

[Trix]

Perhaps if you told us what make of engine you have found we could answer that definitively

 

Richard

 

 

It is posted above..... Yanmar ysm8 could pm you a link if you wish its going in a 27ft springer

[Tony Brooks]

It is posted above..... Yanmar ysm8 could pm you a link if you wish its going in a 27ft springer

 

 

In which case the skin tank (if fitted) may well have its own filler because the it had a direct raw water cooled engine connected to a skin tank when new. If so not T & expansion tank required re my earlier post.

[RLWP]

It is posted above..... Yanmar ysm8 could pm you a link if you wish its going in a 27ft springer

 

Thanks, I missed that. Tony's answer is a good one

 

Richard

[Trix]

thanks Tony very useful reply pm sent

[Naughty Cal]

Fulbourne has direct water cooling. We used to get problems with debris being sucked in and stopping the valves in the (reciprocating) water pump from closing. But no problems since we put several slabs of aquarium filter foam into the mud box. Just requires cleaning occasionally.

 

We drain the engine down whenever the boat is left unattended in winter.

David

 

As we use our boat all winter, we install tube heaters in the engine bay (and in the cabin) to keep the temperature in there above freezing when we are plugged in. If we are out and about the engine will have been run so the heat created from that prevents it freezing over night. If you are concerned though sticking an old duvet or sleeping bag over the engine and heat exchanger helps keep the heat in and the cold out.

[Trix]

I have now been told (by the marina) that keel cooling would be best for my boat, he tells me that it works very well on a springer sounds to me like its just another form of the skin tank idea

[Tony Brooks]

I have now been told (by the marina) that keel cooling would be best for my boat, he tells me that it works very well on a springer sounds to me like its just another form of the skin tank idea

 

 

It is, but just to complicate matters some people insist on referring to skin tank cooling as keel cooling so we still do not know what the marina has in mind. One thing I would never do is to agree to having a conventional keel cooler fitted to a narrowboat unless I was 100% sure it would never get onto canals. They are too vulnerable.

 

I have already said the Springer may have a skin tank and t may be set up to cool a nominally direct raw water cooled engine. It needs someone with a bit of knowledge to look at it for you or for you to post pictures of the whole back end on here.

 

They may also have seen a chance to get extra work and the work I suspect may involve welding water pipes on the outside of the swim(s). That should also be fine as long as the surface area is enough and they can pass sufficient flow.

 

For canal work I have little doubt skin tank cooling is by far and away the best option. If a skintank is needed and it will be too expensive then cooler pipes on the outside of the swim(s) would be the next bets option as long as it was done correctly.