Raw water to keel cooler

[knottybuoyz]

I'm considering buying a keel cooler for our boat project. It seems like the right time to do it while we're building the boat. We have a Yammy 4JH-TE that's about 20 yrs old with only 300 hrs on it. I really like the idea of a closed cooling loop but want to retain the water cooled exhaust. The cost for the cooler is just about a grand.

Anybody done anything similar?

[NCboatrx]

The big advantage of having a keel cooled engine is that you dont have to maintain a water pump">raw water pump with a flexible impeller. Your engine already has a closed fresh water cooling system which is cooled via the heat exchanger and the raw water which cools the heat exchanger is never actually in contact with the engine components. As you want to keep the raw water pump, I dont see anything useful with what you propose.

Like everyone else, I have had some bright ideas for projects on my boat. Occasionally I have seen these same ideas in practice on another boat and have been very thankful that I didn't actually go through with the project as I didn't like the results.

Stanley

[daddle]

I'd guess that the two systems would fail twice as often. Having both sounds like a disadvantage. Keel cooling is popular in fouled water on slow boats. Like canal craft. Raw water cooling works well enough. Ya just have to learn to love that raw water pump.

[DeepFrz]

Unless you go with dry exhaust I really can't see the advantages Rick.

[knottybuoyz]

We'll be spending the bulk of our time in the canals and coastal waterways so a keel cooler is a definite advantage. Anyone who was on the Hudson river this year would attest to that.

Been reading the service manual for this particular engine and it doesn't look like it'd be a very good candidate for a conversion. I'll keep researching.

[DeepFrz]

Rick, what problems did the keel cooler/wet exhaust systems eliminate? You still need to pump raw water into the exhaust system so you need a through hull and strainer and pump.

[Blue Stocking]

Originally Posted by DeepFrz

Unless you go with dry exhaust I really can't see the advantages Rick.

+1 Jacketed dry exhaust would solve your heating need while cruising.

[knottybuoyz]

Originally Posted by DeepFrz

Rick, what problems did the keel cooler/wet exhaust systems eliminate? You still need to pump raw water into the exhaust system so you need a through hull and strainer and pump.

Well a few really. A heat exchanger failure wouldn't be an issue, both cooling loops would be glycol and at over $2K to replace a heat exchanger (if you can even find one) $1K keel cooler is a bargain.

We cruise rivers and canals and hope someday to do the ICW. If you've ever been in the Erie Canal or Hudson river you'll appreciate a keel cooler but with a wet exhaust I'd still need the through hull. A dry exhaust would be better, I understand that but I don't want to have to purchase new materials to build it. I also don't really want a an exhaust stack on the boat either.

We already have our boat heating needs taken care of, thanks Blue Stocking.

Lots to consider I guess.

[swisscraft]

Hi,

if proper done I love the keel cooled stuff, much less to worry about. But proper means you get ride of the raw water circuit which calls for a hot exhaust...

If you so concerned about the rivers you may consider another option: Double the raw water filters, either two side by side with a change over switch or even two separate trough hulls/filters in case of a plastic bag over one inlet. Adding a water flow alarm and you have a prober system which is more built to standard. I guess an additional trough hull/filter plus a water flow alarm should be less than 500.

cheers Marco

[DeepFrz]

I like the keel cooler method too, especially if the engine also uses a dry exhaust. But that takes up a lot of space. Oh, the decisions. Good luck, have you been able to do any more work on your ship lately?

[delmarrey]

Just a note: You will need to inset into the keel or put a protection cover over it to keep it from getting damaged. You will never know if it's damaged until you pull the reservoir cap.

[Chief Engineer]

Most Keel Coolers I have seen are recessed into the hull.

I had a 26foot MWB with a Fernstrum cooler. Used raw water for the exhaust circuit.....worked great....but it has to be zinced well

[knottybuoyz]

Originally Posted by DeepFrz

Good luck, have you been able to do any more work on your ship lately?

Nope. Sitting tight to see what the work/life situation will be in the next few months. I've got enough material to get the hull laminated in the spring and flipped. I have to control my impulse buying now that I may be headed to a fixed income soon.

Thnx everybody for the info on the keel cooler question. I'm still not sure but it looks like it'll be raw water cooled as original just for the sake of cost.