Regarding inquiry form and calculation: Please read the note at the end of this description! Regardless of the type of ship, we offer you the solution with the Bruntons SigmaDrive coupling. There are various products on the market, that try to solve the problem in different ways. The Bruntons SigmaDrive is the only way to eliminate disturbing noises and vibrations of the drive shaft! Special feature: Brunton's Sigma Drive is essentially different in that it is made from a special bronze alloy, no bearings or rubber parts are used and it is very low-maintenance. Instead, special constant velocity joints are used, which are able to transmit the propeller push without thrust bearings. Constant velocity joints are primarily used in mechanical engineering and as drive shafts in automotive engineering. Unlike simple cardan joints, they transmit the rotary motion uniformly. This prevents irregularities in the drive train and additional loads on the surrounding components. SigmaDrives are designed to be suitable for virtually all boats, from yachts to workboats, in fact pretty much any powered vessel with engines up to 1300 hp.Advantages: Noise and vibrations of the drive shaft can be drastically or completely reduced Compact size comparable to standard shaft couplings High performance and low maintenance Perfect alignment of the propeller shaft Simple installation, without fixing brackets or plates for thrust bearings Very cost-effective solution as little or no modifications to the vessel are requiredTo calculate, please copy and paste the following information together with your vessel and engine details into the notes section of the inquiry form: Yacht -  make and model: Shaft diameter Ø:       mm Engine - make and model: Engine power:        hp/kw Engine speed (rpm): rpm Gear ratio:                     :1