Keel cooling question.

[gmarine25]

Can any engine, even one that is seawater after-cooled, be converted to keel cooling? I have always wondered this. If the after cooler was changed from seawater to coolant would this not affect it's rated performance?

 

[F/V First Team]

It absolutely would, this can be solved by either running a much larger keel cooling system circuit or creating an independent one for the intercooling/aftercooling air charge.

 

[Powderpro]

A high hp/liter engine will likely require 2 keel coolers. A John Deere 6081 (8.1 liter) 375hp only requires one keel cooler. I spoke with the Deere dealer a few days ago and they mentioned they were going to keel cool the new 500hp 9 liter which would require 2 coolers. The customer wanted 500hp, but also needed the engine keel cooled. For comparision, the 425hp version of the Deere 9 liter requires only 1 cooler. I believe for most modern engines, a company like Fernstrum can tell you what cooler will meet the requirements of a particular engine.

A friend of mine needed 2 coolers for his 500hp C9 Cat. Another friend needed 2 coolers for a 370hp 5.9 liter Iveco. I believe you can keel cool any engine so long as you have enough cooling capacity.

 

[BillD]

A high hp/liter engine will likely require 2 keel coolers. A John Deere 6081 (8.1 liter) 375hp only requires one keel cooler. I spoke with the Deere dealer a few days ago and they mentioned they were going to keel cool the new 500hp 9 liter which would require 2 coolers. The customer wanted 500hp, but also needed the engine keel cooled. For comparision, the 425hp version of the Deere 9 liter requires only 1 cooler. I believe for most modern engines, a company like Fernstrum can tell you what cooler will meet the requirements of a particular engine.

A friend of mine needed 2 coolers for his 500hp C9 Cat. Another friend needed 2 coolers for a 370hp 5.9 liter Iveco. I believe you can keel cool any engine so long as you have enough cooling capacity.

I'm not up to speed on keel cooling big engines. But in my "mind's eye" the benefits would be @ the least.......

Benefits of keel cooling:
Non corrosive 50/50 antifreeze throughout the WHOLE cooling system.
No raw water pump with an impeller to worry about.
No worries about salt water intrusion backing in through the exhaust.
No worries about the engine "burning" salt water through a leaking aftercooler.
No "winterizing" the SWAC system.

Drawbacks, if at all:

A dry exhaust.
A knot or two of spped loss?

 

[Pedlyr]

What about using a heat exchanger? You install a shell and tube style heat exchanger for the aftercooler circuit. Plumb the raw water to that. May need some space for that, though.

You have to make sure that the intake air is still cool enough. Might be a good idea to get any installation engineered first.

 

[Pedlyr]

Aftercooler

Here are some pics of what saltwater can do to an aftercooler. This is what I have been involved in recently at work. (4) 3406E's - now C18 - rebuilds. 2 complete and 2 top ends.

The condensation tube shows where the "drain" is. They always seem clogged. Note the "waterline'. Forget about zincs. BTW, one engine was leaking ELC

New ZF gear already installed in last pic

 

[Frigate]

Pedlyr,

How many hours were on those 3406Es?

 

[F/V First Team]

Is that a can of Brakleen I see there trying to hide in a towel?

 

[Powderpro]

Pedlyr,

How many hours were on those 3406Es?

And when were they installed?

Keel cooling is definitely more friendly to the engine, but for the speedsters out there, the coolers are a little more drag, weight, and expense. We put a wedge (see pic) in front of the keel cooler to help speed things up and provide some protection, but we also install the cooler very close to the keel for additional protection. This is a single Fernstrum cooler for a Deere 6081 (8.1 liter) 375hp engine. At sea trial this boat was very light, but topped out at 22.7 knots.

 

[Pedlyr]

These engines are about 12 years old and have 16,000 hours on them. Which is really not bad. But they have been apart before. Actually the liners did not look that bad, and they were original. The boat has a short duty cycle mostly inshore. No canyon trips here.

Powder's post reminds me of another thing I have seen on 3406's in another location. Our boats all have engine seachests that are vented.

Some others don't. Just a pipe to the hull. Got to be such an issue CAT got involved. They installed clear tubing for the AC intake and saw a lot of air. And in their eyes cavitation. These people were blasting through engines. If I am not mistaken, I think the lower HP C18's now come with a AC circuit that goes to the plate heat exchanger.

And, BTW Most of the cans of Brakleen end up in the bilge. That is a survivor.