When additional thrust is needed from the Propulsion system such as work boats or towing, additional measures must be taken to limit the thrust loading of the engine. The SigmaDrive STS system incorporates a thrust bearing that is mounted in a thrust bulkhead to isolate the propellers’ thrust to the engine. It uses a combination of three SD units built together. Two of which are incorporated in the thrust bearing and another coupled to the transmission with an intermediate shaft. Like the standard installation the couplings are available for shaft torques of 185 ft-lbs to 4425 ft-lbs with a range of diameters and flange options.
The STS thrust coupling has excellent anti-noise and vibration abilities and also ensures that seals and bearings are always perfectly aligned, reducing wear and ensuring a longer trouble free life for all associated components. The coupling is manufactured from a special bronze alloy that makes it a premium product that is maintenance free. The internal component is hard-wearing with a long service life. No rubber is used in the construction of the SigmaDrive and its unique design compensates for the movement of the engine when under load form the propeller shaft.
STS Sigma Thurst System is available in the following models: STS 550, STS 1000, STS 1500, STS 2250, STS 3000