T1617 Halyard Aquadrive No2 ID2.indd

AQUADRIVEHow does it solve shaftalignment problems?Marine engines are supported ontimber or steel bearers fixed into thehull. These bearers are positioned toallow the engine to line up roughlywith the shaft. The engine is thenadjusted on its mounts so that it linesup with the propeller shaft couplingwithin a few thousands of an inch.All this takes hours of painstakingwork. And then when you launchthe boat, or tighten the backstay on ayacht, it all moves slightly and needsto be done again!The Aquadrive changes all the rules.The propeller shaft fits into theAquadrive’s thrust bearing, which isfixed firmly into the hull. The engineis connected using the Aquadrive’sspecial drive shaft. This allowsmisalignment of 12.5mm (1/2”) – ormore on larger Aquadrives. Enginealignment can even vary whilerunning, so the movement on anolder or timber hull is not a problem.Can the engine beinstalled flat?Marine engines are normally lined upwith the propeller shaft, which hasto angle down through the bottom ofthe boat. The engine therefore endsup with its front higher than its back,wasting precious headroom.Fit an Aquadrive between the engineand the shaft and suddenly you havean angle of ten degrees or more,allowing the engine to be fittedhorizontally. The Aquadrive thrustbearing takes the propeller shaft(and the thrust!), and the specialdrive shaft is simply installed withthe desired angle at each end. Themaximum angle depends on theshaft speed.Will Aquadrive helpme re-engine?The biggest problem in choosing anew engine is fitting it in the existingspace, with the fewest possiblechanges to the craft. Just imaginethe flexibility if you could put anangle between the new engine andthe existing shaft. Or use a longerAquadrive to lower the wholeengine. Or fit the Aquadrive totake out movement between a newengine with flexible mounts andtraditional solid sterngear.Aquadrives installed with 400hpengines on a 15m motor yacht.Aquadrive with a Yanmar 2GMengine in a Contessa 32.How does the Aquadrivehelp with older boats?Older boats have two particularproblems, both of which makelife a misery when re-engining.The stern tube and shaft arerigidly mounted in the hull, sothe extra vibration of a new andflexibly mounted engine willsimply destroy the sterngear.And older hulls, particularlytimber ones, flex a great dealin the water causing the enginealignment to change. Aquadrivesolves both problems by allowingfree movement between theengine and the shaft. Themovement of the new softmounts, and alignment changesdue to hull flexing, can beignored.4