Surf Drive from France Helices
France Helices, the French company that offers a range of trimmable surface drive systems has developed a new model that has rudder steering rather than the normal dynamic steering with the propeller thrust. This new model is aimed at offering a simple solution for boats that have a fairly constant weight and position for their centre of gravity such as RIBs and patrol boats.
Instead of having a drive shaft that can be varied in angle both vertically and horizontally like the company’s well established SDS Drive, the new Surf Drive has a drive shaft that can only be adjusted up and down. This allows the propeller to be trimmed for maximum performance whilst a spade rudder installed immediately behind the propeller is used for steering. The vertical adjustment for trimming the shaft is done by with a hydraulic piston attached to the shaft support.
The Surf Drive is designed for installation using the hull structure at the stern to support the hydraulic ram and the rudder. The thrust from the propeller is taken up by the ball shaped universal bearing where the shaft enters the transom and the shaft can be adjusted up to a maximum of 4° in the vertical plane. The unit is supplied as a complete package for easy installation and France Helices recommend that this drive is used in conjunction with a two speed gearbox for maximum performance.
The initial model of the Surf Drive is capable of absorbing up to 1300 hp making it suitable for boats up to about 20 metres in length. The use of a rudder for steering rather than directing the propeller thrust will reduce the chance of the boat spinning out on high performance craft.
By Dag Pike
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