Keel cooling question

[Guest]

I am looking at a 40' steel hulled displacement cruiser that is for sale. It has a single Volvo TAMD 41 HD engine and keel cooling. Built is 1995, has just under 1300 hrs on the clock. The broker has explained the advantages of keel cooling, but what are the disadvantages? Why is it used so seldom? Can I expect a costly service/repair sometime soon? I believe boat has been used mostly on Continental inland waterways. I would use it for both inland (freshwater) and some coastal work. Other than anodes, does this make a difference? I have a 34' blue water sailing cruiser at the moment, am considering making the big change to have more access to inland waterways, so am a bit of a newbie to this. BTW. how critical are anode changes when going from fresh to salt and back to fresh water?

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[ccscott49]

I don't know of any disadvantages with keel cooling on a displacement boat, at displacement speeds, planing hulls are a no-no, but I wouldn't unduly worry about it, just ensure the cooling system is in good condition, with anticorrosion inhibitors in the colling water. Normally dry exhaust, with less pollution, which is why it's very common in inland boats, as is air cooling. I've seen a few other offshore boats with it aswell.

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[oldsaltoz]

G'day Edward,

The only real problem is the way the pipe is fixed to the hull, the thru, hull fittings and the debris that can be collected by the pipes and retaining bracket.

Also have a good look at the leading edge of the pipe/s, make sure it has a solid fairing block at the front of the thru hull fitting, so if you do manage to hit something heavy underwater, it is deflected and does not rip a pipe or fitting out.

Keel cooling has been around for a long time and is good if the set up is correct; anodes will protect it, just make sure you have the correct type if staying in salt or fresh water for long periods, this applies to all boats, not just keel cooled.

I hope this helps. . . . . .




<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[Guest]

Thanks, Colin and Brian for your comments.

The exposed cooling pipes are a bundle of 30+ copper tubes 2 to 3 ft long recessed into the hull in a rectangular cavity. The cavity is protected with a heavy (steel?) grating gate which is flush with the hull line. They look well protected - even when grounding, it is very unlikely they would be touched. There are a few small barnacles on the tubes. There are anodes at each end of the cavity (as well as numerous anodes around the steel hull). (I have close up photo of exterior installation, but can't figure out how to post it. If interested send me a PM with ur email address.) From inside the hull the thru hull fittings look very robust. This is a production boat from an experienced and reputable Dutch builder, so expect design and construction to be OK, but builder admits not many buyers specify keel cooling these days. I presume the design includes excess heat transfer capacity to allow for minor fouling from slime, barnacles or weed.

From what you both say, sounds like there are no serious downside problems. I guess worst case would be rupture of cooling tubes due to corrosion or damage, with seawater (fresh or salt) entering the normally sealed coolant system. Not sure how this could be detected unless maybe alarm from change in coolant pressure. Certainly running repairs would be impossible. Solution is regular inspection and frequent anode replacement, I guess.

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[oldsaltoz]

G'day Edward,

Testing for leaks is simple, with a cold engine, put a standard automotive radiator pressure check pump on, leave it for 10 minutes, any loss will indicate a leak.

Have a look at the filler and see if it or a standard coolant pressure pump can be adapted to fit.

Also note, some keel coolers are fitted with risers (pipes that extend above the water line) to prevent salt water entering the system, they have a small air bleed at the top that needs to be bled.

Hope this helps. . . . .

Next time you notice a list, try turning the boat around and see if it has changed, may well be wind on mast and tide on keel causing the list.

Hope this helps. . . . .



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[jfm]

totally incidentally.....

...... tcm's boat has keelcooling for his (many) fridges, on a planing hull. The cooling pipes are actually recessed into the hull sides, just above the chine and below the water line, near the transom.

Totally irrelevant, I know

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