Fact & Fiction
about keel coolers, in particular
the R.W. Fernstrum GRIDCOOLER
FICTION: A GRIDCOOLER can't be
used in high speed applications.
FACT: GRIDCOOLERSare
currently being used on high speed crew and patrol craft.The
GRIDCOOLER creates a negligible amount of drag in high speed
applications, and their sturdy design will hold up under the
most demanding conditions.
FICTION: A GRIDCOOLER must be
mounted in a recess.
FACT: Any GRIDCOOLER
may be mounted in a recess or just externally mounted on the
side, bottom or rake of the hull, depending on the vessel design.
FICTION: GRIDCOOLERS require
too many through hull fittings.
FACT: Any GRIDCOOLER
can use our L-Series option which requires only two through hull
fittings, one for the inlet nozzle and one for the outlet nozzle.
FICTION: The GRIDCOOLER is more
difficult to plumb than our competitors' coolers.
FACT: The two-pass
or U-Flow GRIDCOOLER has both inlet and outlet nozzles on the
same end of the unit. The nozzles can use a variety of fasteners
including hose connectors, flanges, or threaded pipe.
FICTION: Grooved round tubing
is more efficient than smooth rectangular tubing.
FACT: This statement
might be true, depending on the cross-sectional area and perimeter
of the two tubes used in the comparison, but don't be misled
into believing that the grooved tubing used by our competitors
is more efficient than our tubing. Efficiency of the cooling
units in question can be determined by simply comparing the size
of one unit to the size of the other. If a GRIDCOOLER and a grooved
tube cooler are sized for the same application, our GRIDCOOLER
will be the smaller unit.
FICTION: 70/30 copper/nickel
is more durable than 90/10 copper/nickel.
FACT: If you
are comparing apples to apples, 70/30 is only slightly more durable
than 90/10 copper/nickel. However, in comparing our 90/10 to
our competitors' 70/30, you may be comparing apples and oranges.
Our 90/10 tubing is twice as thick as our competitors' 70/30.
This increase in wall thickness more than makes up for any differences
in material.
FICTION: Welded and brazed joints
can crack and leak.
FACT: Unlike"O"
ring slip joints which leak under vibration, welded and brazed
joints will not crack and leak under normal operation, and many
units damaged by severe groundings or being struck by debris
will still operate effectively without leaks. In a heavy pounding
sea, kit coolers and their gasket joints can easily fail.GRIDCOOLERS
are built to withstand heavy seas.
FICTION: Brazed coolers can't
be bent to conform to a hull's curvature.
FACT: Because
of the ductile qualities of 90/10 copper/nickel and the inherent
strength of brazed and welded joints, a GRIDCOOLER can be bent
to meet your desired specifications.
FERNSTRUM
Engineered Keel Cooling
QUALITY - Our 100% parts
inspection process and rigorous testing procedures insure that
all raw material and every GRIDCOOLER is built with the same
exacting standards that prompted the U.S. Navy to set their keel
cooling standards by the Fernstrum GRIDCOOLER. Nearly 25% of
the production time for every GRIDCOOLER is spent in inspection
and testing,from raw material to finished product. This level
of quality control insures the dependability and performance
that has kept our GRIDCOOLERSin service for as long as 30 years.
MATERIALS - A standard
series GRIDCOOLER is made of either heavy gauge 90/10 copper-nickel
or 5000 series marine grade aluminum rectangular tubing. These
alloys were chosen because of their resistance to salt water
corrosion and their heat transfer abilities. The copper/nickel
units are silver brazed, and the aluminum units are welded. These
construction materials and methods provide a level of durability
far above any kit cooler.
DURABILITY - While 70/30
copper/nickel is marginally more corrosion resistant than 90/10,its
lower heat rejection abilities make it a relatively poor heat
conductor when compared to 90/10. However, don't be fooled into
believing a kit cooler is more corrosion resistant than a GRIDCOOLER.A
kit cooler uses a very thin walled tube while our GRIDCOOLER
uses a much thicker wall tube. This thicker wall tube, and our
welded and brazed joints, led the U.S. Navy to give the Fernstrum
GRIDCOOLER a 20 year rating.
CONSTRUCTION - Kit coolers
use "O" rings and gaskets to hold their coolers together
for a "tight" seal. Unlike a kit cooler, the welded
and brazed construction of a GRIDCOOLER provides a solid cooler.Welded
and brazed joint construction also eliminates the excess wear
between vibrating tubes and fasteners that occurs with kit coolers.
Sure, you can replace kit tubes a bit easier, but why should
you have to replace tubes?
PRECISION - Every GRIDCOOLERis
built out of high quality pipe and sheet stock, not cheap out-of-round
and thread bare castings or plug-and-pray seals. This allows
us to let you decide how your GRIDCOOLER will attach to your
vessel;and have peace of mind in knowing it will attach properly.
SIZE - The GRIDCOOLER
is the most efficient keel cooler available. Our 90/10 copper/nickel
has 1/3 more heat rejection ability than the 70/30 copper/nickel
used by the competition. Our rectangular tube is much more efficient
than the thin spiral round tube used by the competition. The
size of our cooler can be easily compared to any of theirs. Based
on the same information, our GRIDCOOLER can be as little as half
the size of their bulky kit coolers.
PRESSURE DROP - Overheating,uneven
engine cooling and air pockets in the cooling system are just
a few of the problems associated with excessive pressure drop
in an engine cooling system. Any one of these problems will cause
premature engine wear and engine failure if the problem is not
addressed. It also limits the types of pumps than can be used
for coolant flow. Unlike the kit coolers you may see, our GRIDCOOLER
is designed to create a minimum amount of pressure drop. Kit
coolers using spiral tube create turbulence and turbulence is
pressure drop. Kit coolers with only one through hull fitting
severely restrict water flow, which creates pressure drop.
DESIGN FLEXIBILITY - With
over 8000 GRIDCOOLER models available, we can recommend a cooling
system that meets the unique needs of your engine on your vessel
in your operating environment. Our standard GRIDCOOLER models
can use any one of our five tube types, they can have between
4 and 24 tubes and they can be between 21 and 187 inches long(in
six inch increments). If the standard configuration of a GRIDCOOLER
creates a problem, we can make modifications as needed.
SAFETY FACTOR - Unlike
kit coolers, our units have a 75% heat rejection loading, giving
a built in safety factor of 25% for pump and impeller wear, internal
and external fouling, re-powering, etc.
EASY INSTALLATION - Designed
to be externally mounted or flush mounted on the hull, the GRIDCOOLER
presents no greater problem than ordinary through-hull fittings.The
GRIDCOOLER is a completely assembled unit ready for installation,complete
with heavy neoprene gaskets for sealing the inside and outside
of the hull. If needed, a GRIDCOOLER can be bent to conform to
the hull's curvature.
SUPPORT - With over 50
years experience in the marine engine cooling market, we will
engineer a GRIDCOOLER to meet your specific application and needs.We
can give you advice on cooler placement, installation and service.Should
you require an emergency replacement unit, we can have it shipped
to you within three business days or less.
VARIETY - Kit coolers
might be available in as many as a couple hundred models...GRIDCOOLERS
are available in over 8000 standard models, and a near limitless
number of specials can be built for your individual application.
NEGLIGIBLE DRAG - At up
to twice the size, kit coolers create more drag than our GRIDCOOLER.After
a combination of independent testing by the Vienna Model Test
Basin and in-house testing was completed, it was proven that
the Fernstrum GRIDCOOLER creates less drag than the difference
in drag between spraying and rolling a coat of anti-foulant paint
on a hull.
DAMAGE - If a kit cooler
is damaged, a catastrophic loss of coolant usually follows due
to the loss of tubes. Our GRIDCOOLER does not suffer from this
problem. Because we use brazed and welded joints, the cooler
may leak, but any coolant loss should be replaced
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