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Duramax DuraCooler Keel Cooler
increases heat transfer by 17%.


The Duramax DuraCooler patented streamlined header enhances interior coolant and exterior seawater flow patterns while reducing system pressure drop within the keel cooler unit. We compared the heat transfer efficiency of the traditional square header design to the streamlined header of the DuraCooler.


DuraCooler Flange and Through-Hull

Through-Hull Nozzle Design

Nozzle size and diameter manufactured for specific application. Two piece header design allows for braising on inside and outside of the sea chestheader which, in turn, increases the integrity and reduces the chance of leakage. Sea chest or cofferdam is required by A.B.S.

Flange-Mount Design

This is for non-through-hull applications. Hardware is located outside the hull for easy access. It is recommended when space inside the hull is tight or equipment makes through-hull inaccessible. No cofferdam or sea chest is needed.

Benefits of the DuraCooler Keel Cooler.

Smaller footprint reduces costs

DuraCooler Streamlined design with increased coolant flow to the outside tubes, can reduce the footprint of some units by as much as 42%. DuraCooler units can be easily retrofitted to cool auxiliary engines and other heat sources at a lower cost.

Lower installation cost and low maintenance

DuraCooler one piece construction is compact, making it easy to install. It’s built for long life and low maintenance, with high-strength 90/10 copper/nickel tubing that has excellent anti-fouling and heat transfer properties. It also resists water-flow erosion.

Custom Engineered to fit your exact needs

Your DuraCooler is custom-sized and manufactured to meet your engine specifications, installation space, internal plumbing configurations and operational requirements.


Coolant flow distribution to the outside tubes increased 35%

Coolent Flow

Heat rejection in the outer tubes increased 45%

heat rejection

Note: Study above conducted on a SC-48-96 and equivalent size square-head unit.
Studies conducted by: Flow Simulations Inc. e-mail: info@flowsimulations.com
Overall heat transfer in the DuraCooler SC-48-96 increased by 17% over the square-headed,
traditional design keel cooler unit tested of equal size in initial testing.

In 1997, Duramax Marine initiated a research and development program to identify opportunities to improve the operational efficiency of the square-headed outboard keel cooler.

Finite element computer studies were conducted to determine internal and external flow patterns, pressure drop and heat transfer characteristics for different heat exchanger geometries.

coolerThe traditional square header design system was tested for inefficiencies.
Computer modeling showed poor coolant flow through tubes 1 & 8. It indicated the outside tubes were being used least efficiently even though these tubes had the greatest potential heat rejection per linear foot. Inefficiencies were attributed to the geometric square head design.

Duramax Marine® began to develop a more efficient streamlined header design.
It needed to enhance interior and exterior flow patterns and, at the same time, reduce the overall pressure drop within the keel cooler unit. Resulting in a more efficient unit with a smaller footprint.

The DuraCooler streamline header design was tested.
The tests conducted on the streamlined header design showed an increase of coolant flow of 35% in the outside tubes, along with an increase of heat transfer in the outside tubes by 45%.

pdf   DuraCooler Keel Cooler Brochure
pdf DuraCooler Keel Cooler Installation Guide



Plumbing Options

Single Pass

Nozzles on opposite ends of the cooler to accommodate internal plumbing. Nozzles are available in various lengths and diameters.
single pass

Double Pass

For internal plumbing that requires nozzles on the same end of the cooler. Allows the internally to be more centrally located.
double pass


Flexible Installation Locations

To accommodate hull design, operating conditions and protection from damage.

Side-mounting (PIC)

Near Propeller

Recessed Mounting

Fairing Block Protection Bending To Fit Curvature


Duramax Marine® is committed to continuous improvement.

In 1998, Duramax Marine® built an 800,000-gallon testing facility to better emulate marine conditions in a controlled environment. The testing facility can test keel coolers 20 feet long and weighing as much as two tons. Temperature drop, pressure drop and flow rates can be monitored and recorded. Duramax keel cooler experts operate this facility. It shows their commitment to the marine industry to help vessels meet the ever changing cooling requirements of engine ecological advancements needed for a clean new world.

Pond Test DuraCooler
  Duramax® is a registered trademark of Duramax Marine® LLC.
DuraCooler® is a registered trademark of Duramax Marine® LLC.

Duramax Marine LLC is an ISO 9001:2008 certified company.
17990 Great Lakes Parkway, Hiram, Ohio 44234 U.S.A.  |  PHONE +1 440.834.5400  |  FAX +1 800.497.9283 USA & Canada or +1 440.834.4950 
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