On the Level

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Maintenance is key to ensuring your stabilizers  reliability.

MurphyLaw —whatever can go wrong will, at the worst possible moment —isn t true science. Or is it? Murphy dictates, for example, that stabilizers will fail in rough seas, but this is also when they are working the hardest. Fortunately, hydraulic, pneumatic and active gyrostabilizers are robust and reliable. Just a little routine maintenance should keep Murphy at bay.

Hydraulic systems work for many years with minimal maintenance. an eye on oil level, check the temperature, and periodically inspect the system,”says David Yish, customer service manager for Naiad Dynamics.

Hydraulic oil is cooled to below 165 degrees Fahrenheit by a heat exchanger at the stabilizer unit, typically fed by a main engineraw-water circuit. These coolers donrequire regular cleaning like engine-cooling systems. Just check the zinc every few months.

As long as it remains cool, hydraulic oil lasts a while. think they need frequent oil changes, but without the combustion of an engine, that oil should stay clean,”Yish says. Monitor the gauge built into Naiadfilter assembly, marked green, yellow or red to indicate filter life, but Yish says oil should last three years or about 1,000 hours.

Inspect seawater and hydraulic hoses and replace them when you notice cracking or swelling, particularly near fittings. Hydraulic pumps, which are typically mounted on a main engine, seldom fail, but they deserve a visual inspection as well.

Stabilizers right a boat based on input from a gyroscope —a disc spinning at high speed that resists being tipped like a childtoy top. Naiadgyro requires no scheduled maintenance. a decade or two, the gyro might go out of calibration,”Yish says. Off-center fins or sluggish operation are signs. Naiad can rebuild the gyro or replace it with an electronic controller.

Maintaining seals where fin shafts penetrate the hull is crucial. exposed to seawater is stainless steel, but in some places we need the strength of carbon steel," Yish says. Those carbon-steel parts are sealed within the grease-packed actuator housing. Seawater penetrating that grease may go unnoticed for many months. Tan grease seeping from stabilizer-fin actuators isnabnormal, but oozing gray grease indicates seawater infiltration. three years, remove the fins and replace those seals,”Yish advises.

Pneumatic stabilizers use air rather than hydraulic fluid to spin the gyroscope and activate underwater fins. Ensuring delivery of clean, dry air is the overriding maintenance concern.

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have many customers who replace their filters every year or 400 hours and never have to go into the system,”says Zeyad Metwally, president of Gyro-Gale. But ignoring those filters is a wide-open invitation to Murphy.

Most Gyro-Gale systems draw air from an engine-driven compressor. This hot, damp, oily, dirty air goes through a cooler, typically a heat exchanger plumbed into an engineraw-water system. (Gyro-Galeheat exchanger is designed without zincs.) From there, air travels through a water accumulator and two filters —one desiccant that removes moisture and then a 0.02-micron particle filter —and then into an accumulator tank.

That accumulator tank is the first place problems are likely to show. Periodically open the drain on the bottom. It should never release more than a tablespoonful or so of water. Another indicator of the setuphealth is a pair of air-silencing filters on discharges inside the systemcontrol box. should remain golden,”Metwally says. they turn dark, the filters arenworking properly.”Dark, oily residue on the inside of the control box indicates that there are severe filter problems.

After the accumulator tank, air passes through an oiler that lubricates pneumatic components. Check it once in a while and top it off with ordinary mineral oil from the pharmacy Service Gyro-Galestabilizing fin seals every two years. If these seals fail, water weeping into the boat will leave telltale water marks or salt around the fin actuator. Pneumatic stabilizers should never

release any air except at the control unit in the engine room. Listen or feel for leaks. Like Naiad, Gyro-Galeunit requires no scheduled maintenance. It too offers an upgrade to an electronic control.

Active gyroscopic stabilizers are new to the yacht world, but the technology predates the ships of World War I. Rather than using a small gyroscope to sense motion and then control a set of fins, active gyros employ a large, heavy gyroscope that resists being upset and applies that force directly to the boats hull. Imagine that childspinning top connected to a rocking chair. As that chair tips, the spinning top will force it upright. Now imagine that top is two feet across, weighs 400 pounds and is connected to a boat.

is very little to maintain on a regular basis,”says Stephen Shaw, Seakeeperglobal field service manager. motor, bearings and flywheel are all within the sphere, which is vacuum-protected from salt air.”Its 10-amp-draw alternating-current motor and spinning flywheel do generate heat. use a glycol [antifreeze] loop to cool the system and raw water to cool that glycol,”Shaw says.

A pump and sea strainer, like those found on small marine air conditioners, supply that raw water. Keep the strainer clean, check the zinc in the heat exchanger every three months, and monitor the glycol level through the sight glass. you lose raw-water flow, an alarm sounds on the keypad,”Shaw adds. of the action takes place inside the sealed sphere, so we rely on our monitoring equipment. If there is an issue, the gyro will tell you about it and shut down to protect itself.”To avoid problems offshore, inspect for seawater, glycol or hydraulic fluid leaks as well as chafed hoses or wiring.

Gyrostabilizers donhave fins beneath the water, and Seakeepersystem employs only a very simple hydraulic system with no pumps or filters. Every 2,000 hours, the hydraulic circuit is flushed and the glycol coolant and a few bushings are replaced. Every 10,000 hours, the entire core is rebuilt.

A clogged sea strainer is a potential problem, but this is likely to happen in shallow water, not out in the ocean where stabilizers are needed the most —at least this once besting the wily Murphy.

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