DSK wrote:
Joe wrote:
The oragami boat here used the rudder skeg as a keel cooler.


That is a good idea, but you don't even need to do that.
Just run parallel cooling lines (small diameter tubing works
best, but you have to make sure they will carry enough flow)
in metal-to-metal contact with the hull. The entire hull
will dissipate the heat.

Are you saying run tubing inside the hull, but in contact with the
hull?
If so that would be a maintance nightmare.

One of the best features in the Oragami boats and the Strong All yachts
is the lack of framing. Framing is metals boats worst maintance
problem. You need proper limber holes and they all need to be kept
clean so any moisture will make it to the bildge and not be trapped and
develope frame pools. There were two spots on the hull of redcloud I
had to replace, and both were in the sail locker where water pooled
because it had no way to drain thanks to no limber holes up high. A
frameless boat is perfect. A copper nickle frameless hull 5MM thick
would last 300 years and never need painting.




Has 25 gallons of antifreeze in the rudder skeg, just wonder if the
antifreeze is a good enough rust inhibitor

Aluminum doesn't rust. Doesn't need an inhibitor.

His boat is steel and I guess he using anti freeze Glycol whatever...


... if the keel skeg will
radiate the heat well enough. If so... it sure beats the hell out of
having cooling channels or pipes coming out of the hull.


That's for boats made of wood or foam core or some other
insulator.

All the steel supply boats I ran (225-300fters) had keel coolers.
4"X2" steel channels about 100' long welded to the outside of the hull.
Simple and worked great.



Another clever idea for a heat sink is to put a coil in each
thru-hull. Some refrigeration units have these as an option,
gets similar efficiency to water-cooling but you don't need
a pump.

Just a coil before the exchanger to cool the feed water?

Joe

DSK