T1617 Halyard Aquadrive No2 ID2.indd

WHY FIT AN AQUADRIVE?An Aquadrive system willreduce structure bornenoise and vibration by up to90%. It will reduce overallnoise levels by up to 75%.It will end shaft alignmentproblems on installation,and for ever more!It will allow the engine to be installedflat, because the Aquadrive allowsangles between the engine and theshaft. It will ease problems whenre-engining. And it’s a gift when reenginingan older boat.How does it removeso much noise?Marine engines traditionally havebeen coupled directly to thepropeller drive shaft, perhaps witha stiff flexible coupling between thetwo. Most of the vibration is sentstraight down the shaft, and theengine mounts can’t do their jobproperly because they are strainedforwards by propeller thrust. Sovibration gets into the hull, andvibration equals noise.The Aquadrive puts free movementbetween engine and shaft. It takesthe propeller thrust straight onto thehull, and allows free movement ofup to 25mm between engine andshaft – up and down, sideways, orfore and aft. No vibration goes downthe shaft, The mounts are no longerstrained forwards by the propeller’sthrust. The Aquadrive allows somuch movement that you can evenfit special softer mounts on enginesof four cylinders or more.What’s the result?Modern hulls are made from GRPor steel. Both materials carry noisebadly, so structure borne noise isa particular problem. The chartshows just how much noise can becancelled by fitting Aquadrive.2