Practical Boating - Seakeeper

98 Out of the Ocean – blue cod 100 Wrap your boatBONUS VIDEO(just forward, midships) andmore importantly I wantedtwo large water tanks to portimproved stability. When youand starboard.head offshore for a few days ofSqueezing the gyro into thegamefishing you often find yourself inengine room demanded some creative choppy conditions with a big swell running.thinking, and the job fell to Dean Ryder, “We have a high tower on thisowner of Westpark Marina’s Motor Yacht boat, and sitting up there the roll isService Centre.accentuated. Anything that can reduce“We removed the port water tank, roll is a huge advantage and it makesshifted the generator into its place and gamefishing much more appealing todropped the gyro into the generator’s charterers, particularly if the guests havebed. Eliminating one water tanka susceptibility to sea-sickness.”compensated for the gyro’s weight, and The Volvo’s IPS – with its pinpointthe new configuration ensured that the manoeuvrability – comes with a Dynamicboat remained balanced.”Positioning System (DPS) option that’sThe gyro’s weight was actually a also very useful says Ian.relatively minor issue.“It keeps the boat in one spot, and that’s“Of much greater concern is the angular very important when fishing for hapuka oror ‘righting’ torque the gyro imparts to the broadbill in 200 metres of water. With thesehull,” says Dean. “It’s an enormous force, species, you want to fish on the edge of aand we had to beef up the bed for the gyro big drop-off and you need to maintain yoursignificantly using a robust timber structure position very precisely.with glass overlay.”“The skipper’s job is to find theThe finished installation looks superb perfect spot and DPS keeps the boat– you’d swear it was part of the original over that spot. With the gyro, we nowbuild – but at a total cost of around are also able to remain stable. That’s$100,000, it wasn’t a frivolous upgrade, makes the fishing much more pleasantso why did Ian want to do it?and a lot safer – you’re less likely tolose someone over the side. WhenFISHING EASEfishing at night we also put lights“Two reasons. I admit to being something over the side, and if the boat is stableof a magpie – I like new gadgets – and there’s less chance of lines and cablesthe technology appealed to me. Butbecoming entangled.”w w w . b o a ti n g n z.c o.n zLeft: The gyro is mounted on a heavily re-inforced bed, just forward of the twin engines;The gyro’s flywheel spins at 8000rpm and can be disengaged with the touch of buttonIan is delighted with the gyro.“My research suggested it could reduceroll by 80 to 90 per cent, and our experienceso far has corroborated that. All of my regularfishing mates say it’s the best stabilisingtechnology they’ve ever experienced. Whenmy wife comes along for a cruise, the firstthing she says is ‘Is that thing on?’”Another advantage is that, unlikemore conventional ‘fin’ stabilisers, a gyrostabiliser doesn’t require any throughhullcutting.“There are no appendages so thereis no drag,” says Ian. “And where the finstabilisers need speed to be effective, thegyro works perfectly when the boat is atanchor or simply drifting.”Ian has just appointed charter boatveteran Brodie Newton as Matariki Nui’sskipper, but despite working on boats allover the world, Newton had never previouslyexperienced the gyro technology. He sayshe’s amazed at how quickly and effectivelyit stabilises the vessel.TransmissionsControl Systemsservicing the marineindustry since 19180612802Pacific Driveline LtdTel: 64 9 262 3241 • 55G Druces Road, Manukau.Email: pacdrive@clear.net.nzwww.pacificdriveline.co.nzStabilizer0812415subscribe online at www.mags4gifts.co.nz/boating-nz 95

HOW IT WORKSMechanical engineers can read aboutthe physical laws governing the gyro’soperation at www.seakeeper.com wherethey’ll find plenty of fascinating informationabout moments of inertia, angular velocity,angular momentum and torque.For mere mortals, think about the timeyou spun a bicycle wheel, holding on to itsaxle. The tendency for the wheel to wantto remain on one ‘plane’ is a simplifiedexample of the forces at work with the gyro.The stabilising force is generated by theflywheel spinning at 8000rpm. When theboat rolls the ‘counter-acting load’ thegyro generates and transfers to the hull isimpressive. When you consider that MatarikiNui is an 18-tonne vessel, you can see whythe gyro needed to be mounted securelyonto the vessel’s frames.A network of built-in, integratedsensors constantly measures the vessel’smotion, counter-acting the effect of eachwave. Sensors measure flywheel bearingtemperatures, vacuum pressure, motorand drive temperatures, gimbal angle,brake pressure and boat motion.The flywheel spins in a near vacuumwhich effectively eliminates the powerneeded to overcome air friction, so theflywheel can spin at a high speed:the higher the speed, the smallerthe flywheel because angularmomentum is proportional tospeed. I knew that.Interestingly, thegyro does nothave to be locatedon the boat’scentreline, thoughit is recommendedthat it is mounted aft,particularly in high speed vesselswhere the vertical accelerations upforward might exceed plus or minus 1gee.There is also no ‘one-size-fits-all’.Seakeeper gyros come in a range ofsizes, and in larger vessels two (ormore) units are mounted in tandem.The gyro operates on 240 voltsAC which means the vessel’s dieselgenerator must be running, but as Ianpoints out, the generator is runningall the time in any event, to powerMatariki Nui’s air-conditioning system.Running costs are minimal and noiseindiscernible.Seakeeper gyrostabilisers are becomingmust-have items inluxury craft around theworld, as well as findingfavour with operators ofcommercial vesselsDOES IT WORK?Cynical journalists rarely admit to beingimpressed, but it would be churlish of meto downplay the gyro’s performance. It is,quite simply, remarkable. It’s very easyto compare the boat’s motion with andwithout the gyro thanks to a switch onthe dash. Switching it off doesn’t stop theMarlin - Broadbill – KingfishHapuku – SnapperFish - Dive - CruiseLuxury - New Riviera boat (Dec 2010)Affordable - Tailored ratesCaptained by Brodie Newton,vastly experiencedInternational Gamefishing SkipperManufacturer of Southern Boats and Lazercraft Boats & also Specialising in Custom Builds over 8m0812241• Riviera 43 Offshore Express• Tuna Tower with full driving helm• 880hp • Seakeeper gyro stabiliser• Latest Raymarine electronics including72 mile radar • Sky TV • Wi FiBay of Islands - Auckland - Marsden CovePhone: Brodie 027 295 9500 Freephone: 0508 SPORTFISH www.sportfishingcharter.co.nz96 Boating New Zealand August 2012

flywheel’s spin but merely disengages itseffects by isolating the hydraulic rams.Ideally, we would have liked a snottysouth-wester barrelling up the HaurakiGulf to sample the gyro’s characteristics.Perversely, the weather gods provided acloudless, breathless day, with barely aripple in sight, so we opted for the nextbest thing: playing in the wake of theWaiheke ferry.Lying side-on to the wake without thegyro produced a stomach-heaving roll andwhile up in the tower, a white-knuckledgrip. Three seconds after switching it on,the gyro dramatically stabilised the boat,virtually eliminating the roll. We did thisa number of times, switching betweenmodes to gauge the gyro’s effect, and itwas very impressive. Check out the videoat www.boatingnz.co.nz and make yourown judgements.Remarkably, Seakeeper has only beenin business for five years, but its gyroshave quickly become must-have optionson top-of-the-range European yachts.Builders such as Sunseeker, Fairline,Heesen, Princess and Leopard, andAustralian builders Riviera and Maritimo,have all begun fitting the units. Frenchbuilder Couach has made the gyrosstandard equipment on every yacht.Seakeeper says its sales in the firstnine months of the year were three timeshigher than for the same period a yearearlier, and it expects sales to doubleagain next year. It is fielding a lot ofinterest from operators of wind-farmservice vessels and pilot boats, and hasalso installed its gyros on military craftsuch as torpedo recovery vessels.Matariki Nui is the first New Zealandboat to be equipped with the SeakeeperM8000 gyro, although another is beingfitted to a new build.For more information on the Seakeeper,contact the agent, Manukau’s PacificDriveline Ltd, on 09 262 3241.Manufacturer of Southern Boats and Lazercraft Boats & also Specialising in Custom Builds over 8m081223918 clearwater cove, hobsonville, west harbour. ph (09) 416 1179 www.motoryachtservicecentre.co.nzsubscribe online at www.mags4gifts.co.nz/boating-nz 97