PYI fits Sonihull, keeps keel cooler clear

Sonihull, the world’s leading ultrasonic antifouling system, has been installed on a Nordhavn 55, by USA distributor PYI Inc., to cure a persistent keel cooler bio-fouling problem

To cure a recurring problem of marine bio-fouling, a Nordhavn 55 owner from Maine, USA has fitted a Sonihull ultrasonic antifouling system to the internal pipework that feeds his vessel’s Fernstrum keel cooler.

Previously, the underwater heat exchanger was prone to heavy fouling by weeds, barnacles, and mussels. This would impede water flow around the keel cooler and reduce the effectiveness of the cooling system, putting extra strain on the engines and adding to the annual lift-out and service costs.

Here’s a comparison of the Nordhavn 55’s keel cooler after one year in Maine waters

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Here’s a view of the internal pipework before and after the Sonihull installation

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“The photos speak for themselves,” says Dominic Findlow, Technical Director of Sonihull. “The owner took them in the same boat-lift after voyaging nearly 5,000 miles each year over the same waters, including six-month periods of stationary mooring in Maine waters.”

By fitting the Sonihull system to the metal pipe fittings inside the hull, the system can transmit strong ultrasonic pulses throughout the heat exchanger, protecting any surface that is in contact with raw seawater. The pulses create a microscopic layer of micro-cavitation which disrupts the first stages of the food chain and prevents further colonization and attachment of weeds, barnacles and mussels.

Because the only mounting surface available was a short section of threaded bronze inlet pipe, a novel solution was employed. “One Sonihull transducer was bonded to a stainless steel plate which was welded to a threaded collar. As there was no space to screw the assembly into position, the collar was machine split and then secured to the threaded pipe by two locking bolts,” explained Findlow. “A second Sonihull transducer was bonded to the inside of the hull, directly aft of the keel cooler.”

“These results in the leisure sector are testament to the results we achieve in the commercial sector, where operators are saving up to 95% of their capital and maintenance costs when protecting their box coolers with Sonihull instead of impressed-current antifouling systems.”

Sonihull is a zero-harm solution. There are no poisons, or biocides leached into the marine environment, no microplastics are shed from ablative coatings and no toxic metallic ions are left in your wake.

Sonihull, The future of antifouling, now