FAQ - we have answers to your qustions


In order to recommend the best cooling solution for your application, our sales and engineering team will need to know specific information about your engine, vessel, and operating conditions. The recommendation form lists the specifications we will need. Once the form is completely filled out, our team will be able to determine the size of cooler necessary for your application. If you do not have all the engine information required on the recommendation form, we will help you. Fernstrum maintains current files on all major marine engine manufacturers.

The Model Number and/or Serial Number are stamped into both ends and/or on the top of the header.

Included in an anode set are two anodes, four mounting bolts, and four washers. (In most cases, one anode set is required per GRIDCOOLER Keel Cooler.)

A gasket set includes all of the gaskets normally supplied with a new cooler. This includes gaskets that are mounted internally as well as externally on the hull. If isolators are standard equipment on your cooler, they will also be provided in the gasket set.

A compression sealing kit is used when a GRIDCOOLER Keel Cooler is mounted utilizing a cofferdam (top hat) installation. The kit consists of additional washers that are unfinished on one side and soft gaskets.

This kit is an added measure to help prevent the pressurized coolant within the cofferdam from potentially seeping around the through-hull pipe fitting.

faq Compression Sealing Parts Placement

Do not exceed 35 PSI (2.41 Bar) when pressure testing a GRIDCOOLER Keel Cooler.

When recessing coolers for 0 knot hull speed applications (generators, air conditioning, hydraulics, etc.), we use a thermal convection current of ½ mph to determine the speed of seawater flowing past the cooler. 

This current is created by the cooler heating the surrounding seawater during normal operations. This heated seawater must be allowed to freely exit the recess, or the cooling system will overheat. Some suggestions on recess design and location can be found in our Installation and Maintenance Manual.

Shallow recesses, like the ones we describe in our Installation and Maintenance Manual, will have little to no effect on the size of a cooler. The key parameter to proper design and placement of a recess is ensuring that the heated seawater can easily escape the recess box.

While we do maintain a number of different units in stock, we typically size each GRIDCOOLER Keel Cooler to specifications required by your engine, vessel, and operating conditions. We will certainly take a customer’s request for a stock cooler model into consideration when determining the appropriate cooler model.