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Tom Lawler of Ledyard, CT asks:

Your 5/10 post said you had a cooling problem with your active stabilizers. Specifically what is the problem and what have you tried to fix it? Have you contacted the manufacturer for advice? How was that experience? I've heard good things about their product. I guess this is a testimony for having paravanes - less mechanical things to break. The biggest concern is having a safe way to deploy and retrieve them without having the boat or crew attacked by the birds.

Jeff Leishman responds: We use a 12v Jabsco reversible Water Puppy pump to cool the Naiads. This pump is sold as a continuous duty pump with heavy duty brushes for long life. In each pump failure (3 total) the brushes failed. Cooling the stabilizers on a dry exhaust keel cooled boat presents a challenge. On a typical wet exhaust system you can simply divert a small amount of the raw water from the engine cooling to cool the system. With a keel cooler, that is not possible. We have been experimenting with other ways to cool the systems, including a separate keel cooler to cool the oil. To date this is still in R&D. We also have a system that American Bow Thruster has developed for us which uses the return oil line to drive a hydraulically driven water pump to cool the system. This has been somewhat successful but the early versions were not the best solution. The latest version seems to be the answer for now.

Naiad has been unable to give us a good solution other that what we are currently doing with the electric water pump. The ABT system is good but quite pricey ( however given the fact that we have burned up three 12v pumps maybe the cost is not so bad?) As you can gather this is a big subject and has many solutions - each one presenting its own set of problems.

The paravanes have been good but not as good as the Naiads. They slow the roll rate down and the roll angle but they do not take the roll angle down like the Naiads. We have a system for launching and retrieving the fish (or birds) that takes all the hassle and danger out of it. It would take too many words to explain the system in this forum but next time you're at a boat show, someone from PAE would be glad to walk you through it (assuming the boat has the paravanes). We have been making the Nordhavn 46 for about 12 years.

 

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