To marinize or not to marinize that is the question

[treeclimber@xtr]

A friend who is a shipwright told me I could set up a heat exchange by pipeing water from the radiator in a loop around the keel. I would have to create cavity (weld a plate along the length of the keel on both sides- Its a steel hull) and pipe the water from the radiator through this, then I can use any normal diesel engine. It is for a 40' steel sail boat. I'm not that keen on altering the shape of my boat where hull meets keel, not even a little bit. Its such a lovely shape already but not have to marinize is very attractive. A friend of my friend has circumnavigated three times with the same engine.
Opinions?

[FAST FRED]

We have a 50 ft Navy Utility Launch that is GRP.

Its DD 6-71 has a dry stack and all the cooling is two lengths (21ft) of 1 1/2 pipe with a close nipple and two 90deg at the "far end".

This system of keel cooling has worked for years , in warm Florida waters.

Cheap , reliable and functional,

No extra water cooling pump to maintain is great for FL sandy waters.

FF

[Landlubber]

My mate who has made over 70 steel boats, regularly builds in a double bottom, it is filled with the radiator coolant mix like glycol and the engine runs through the double bottom fresh water system. i have not heard of any problems....are you there Mr. Yan?

[Manie B]

You can mount it on the outside of the hull quite easely here is a link http://allweatherboats.com/id10.html i am sure we will be seeing a lot more "old" technology with the current world wide inflation

[Eric Sponberg]

See Dave Gerr's article on dry exhaust in Professional Boatbuilder magazine, issue 111, page 66, "The Dry Exhaust--Part 1", which you can read on-line at:

http://www.proboat-digital.com/proboat/20080203/

The article covers the design information you need to know in order to size a proper keel cooling system.

I hope that helps.

Eric

[sal's Dad]

If you have a metal hull, just weld half-pipe on the INSIDE of the hull, anywhere you like, below the waterline. Make a single, continuous loop, sized appropriately for your engine. There was a lot of discussion a couple years ago, either here, or on the Metal Boatbuilding forum. [edit: http://www.metalboatsociety.org/ has extensive discussion of just these issues ]

If you want heat sometimes, put a Y-valve to route the coolant through pipes in your cabin sole!

[FAST FRED]

"If you want heat sometimes, put a Y-valve to route the coolant through pipes in your cabin sole!"


I would add an electric circ pump., so if heat is required after shut down you can get it for free from the engine mass.

With the Y valve in HOT weather the circ pump would cool the engine , making it easier to be aboard after shutdown.



We have used the concept of an electric extra circ pump in our RV bus conversion , an 8v71 has enough retained heat (3000lb engine) to warm a cool evening at little cost .

FF

[treeclimber@xtr]

cool thanks, good info. I'm gonna do that.