History

The Evolution of the Drive Cooler - The first Drive Cooler was introduced in the 1980s, when there were only a few manufacturers and they all sprayed water on the top of the drive. The first one, made by Hill Propellers, had a solid pick up tube and the others followed with flexible tubes, but they all had one pick-up port and one dump port on the top. The flexible tube style came in a few versions. Eddie Marine used a triangular shape mounting bracket with a big hole in the center. It was a little bit fancier looking than the solid tub design but did nothing to improve the cooling capability. Imco Marine used a polished cap that covers the top of the drive instead of the triangular shaped mounting bracket. They changed the angle of the spray from 90 degrees straight down at the top of the drive, to the back of the drive and skipping the water over the top. The “cap” was open in the back and did nothing to improve the cooling, but it was polished and looked nicer so it began to out sell the others. It didn’t take long for other manufacturers to enclose the back of the cap, “trapping the water on top of the drive” and claiming it to be an improvement, when in actuality, it also cooled the drive oil by about the same as all the others. Tests done by Hot Boat Magazine and published in their April 1997 issue, found this technology of spraying the top surface of the drive to cool the oil inside by about 25 degrees. - In 1999, Simrek introduced the Multiport Driveshower. It is fed by twin pick-up ports for twice the water volumes and targets the top and both sides of the drive with multiple dump ports. It was tested by Dockside Magazine, and the results were published in their August 1999 issue. They found that it cooled the drive oil by 50 degrees. That’s twice the cooling than the other systems that were previously tested by Hot Boat Magazine. Now many of the other manufacturers were scrambling to come up with a gimmick to sell their products. Within a few months, most of the manufacturers were also claiming to be cooling the sides of the drives. To date, there have been no test results to prove that their system is any better than the systems first introduced in the 1980s. - Why twice the cooling? Is it the two vs. one pick-up ports, or is it the multiple dump-ports that can account for the big jump in cooling capacity? The answer seems to have been provided in the magazine article in Family & Performance Boating May 2003 issue when they also tested the Simrek Driveshower. In 2000, Simrek introduced the Halo Design which doesn’t spray any of its cooling water on the top of the drive. During the testing, they found that by targeting only the sides of the drive, instead of the top and sides of the drive, Simrek had increased the cooling protection by 10 degrees over their other model that does spray water on the top of the drive. So if a system that targets only the sides of the drive gets 20% more cooling than the one that dispenses some of the water on the top, then why do most cooler manufacturers sill insist on targeting the top bearing cap and pre-heating the water before it runs down the sides or worse yet, simply targeting the top bearing cap. Once you understand the concept of efficiently cooling a drive, it becomes easy to see that these other systems are nothing more than gimmicks. If they can make it look nice or convince you that it will work, maybe they can sell it and most often at a higher price. Have you ever seen independent test results on any of their products? If a magazine tests a product, the results get published whether the manufacturer wants them to or not. So if you don’t see any testing, then they must not want to the results to be disclosed. - In 2000, Simrek also introduced the 90 degree pick-up port and received a US Patent. This also sent many of the manufacturers scrambling to come up with a solution for their products. To minimize costs, some did nothing. Even after the 45 degree pick-up ports used on their systems were tested and the results of their failures were published in a Hot Boat Magazine article, April 2000 issue. You can still find pictures in many magazines, of boats with one of these 45 degree drive coolers and it is obvious by the picture that the drive cooler is not spraying any water onto the drive. - With the introduction of the Multiport Drive Shower® in 1999, the industry saw a 100% increase in the ability to cool a stern drive. Since then, many have tried to make improvements to this design and claim to be the "best", but without unbiased testing done by an independent testing facility, the public will never know. There has however been the introduction of a lot of gimmicks to the market. Coolers that replace the top bearing cap or the back inspection cap with a very expensive and not very efficient cooling system are one of the worst gimmicks. The chambers that they use inside the replacement caps are way too small to process the water volumes necessary to cool the drive oil. They are closely followed by the “cover styled” systems that use attractive finishes, elaborate designs and exotic shapes to entice you to buy one because it "looks nice and it should work". Before you buy any drive cooling system, ask to see the independent test results that documents that the system does what it claims to do. Don’t rely on the salesman’s redirect, your buddy’s opinion, “well,it looks like it should work” or claims made by the manufacturer. The proof lies in the ability of the system to cool the drive oil. Isn’t that why you are buying it in the first place? A blown drive with a pretty drive cooler on it won’t be of much value. - Reprints of all of the articles mentioned, as well as some others, are available on driveshowers.com