Keel Cooler

[muckypup]

Reading the Circumnavigator II which I downloaded off the Nordhavn website it says the N55 has a "Fernstrum Grid Cooler" keel cooler. Anyone know what these are for and why one would be needed?

S.

 

[Talbot]

almost certainly a cooler for the refridgerant in the fridge/freezer, rather than relying on air cooling.

 

[Ifraser]

My understanding of a keel cooler is that the engine coolant is circulated through a grid on the hull that is in the sea water. This eliminantes the need for a heat exchanger. A keel cooler in its simplest form as used on some basic fishing boats is just a pipe run the length of the keel that the engine coolant circulates through. I'm not sure why Nordhavn would use this system instead of a heat exchanger....maybe less moving parts ie no sea water impeller but if its better then why do most manufacturers use heat exchangers....That my understanding of what it is but as you can see don't fully know what the pro's and con's are...cheers Iain

 

[Nautical]

Will be a 'keel' cooler, rad runs lengthwise of the keel and coolant is cooled from the keel rad acting as a heat exchanger to the sea water. Basically means no under water skin fittings and no raw sea water in and around the engine through the heat exchanger. Most Nordhavn's are also dry exhaust if Keel cooled so quieter and the nasty fumes are well above your s/structure rather than down at water level.

 

[Piers]

Keel Cooling cools the anti-freeze/water mix in the engine block, hence eliminating the need for sea-cock, heat exchanger, impellor etc. Arguably less to go wrong, certainly less maintenance, but a more expensive installation. Draw backs to dry stack exhaust are the potential emission of sooty muck (especially on start up, although modern electronics may reduce this), and taking up of valuable cabin space with the oversized 'muffler' and the dry stack itself.

Some boats use keel cooling and still have wet exhausts.....

 

[andyball]

[ QUOTE ]
Some boats use keel cooling and still have wet exhausts.....

[/ QUOTE ]

ours does - with a metal impeller s/w pump ( like a HD pond pump or heating pump ) - presumably to reduce wear & potential troubles in dirty dutch canals...


We have a v wide double skinned keel to provide the cooling, downside is the huge amount of antifreeze required & need to close seacock before cleaning s/w strainer, since the centrifugal pump won't draw if the inlet pipes are empty ( not really a drawback - just different )

 

[contessa26]

Hello! Agree with everything that has already been stated - as always - plus another couple of features of what you call 'keel cooling' - most systems I've seen in work boats and fishing boats: no (corrosive/problematical?) salt water in engine system; err, some systems don't need to draw in salt water/river water via a strainer, so eliminate this device getting blocked, etc; some work boats or rescue boats on ship's davits (for example), allow engine to be started out of the water, prior to lowering/launching... err...
Best regards

 

[Nautical]

Fair comment and agree but most seem to be dry exhaust as many are commerical boats or long distance endurance type thingys.

Think I got the mechanicals correct or are you saying I am wrong?

 

[Piers]

You are right - I just wanted to put the specifics down.