Marine Gears

Marine Gear Units are ideally applied in Ships for:

Diesel engine propulsion lines
Gas turbine propulsion lines
Steam turbine propulsion lines
Electric motor propulsion lines
Combined propulsion lines

Marine gears are referred to the complete set of gears that is applied in the marine applications. Luxury yachts, Commercial ships, Cruise liners, Warships, patrol boats or high-speed ferries are all fitted with marine gear units.

In Marine Gears physical, performance and other features vary considerably. A Marine Gear that has a high performance can have a size in the range of 300 mm to even 5 meters. Power transmission can start from say as little as 225 kilowatts to astronomically high rate of 50,000 Kilowatts. Not only huge power transmission marine gears are also associated with high speeds. For example the gears found inside a fast craft vessels are capable of generating speeds that is at the least 25 knots or 29 mph., are considered high performance. A high performance Marine Gearbox can have a power/weight ratio that is more than 1.5 kilowatts/kilogram and a pitch-line velocity of a minimum 120 m/sec.

Prime Features of Marine Gears
Marine drives are supposed to meet stringent demands. To rise up to such high expectations Marine gears comes with some features that are unique in itself. Discussed here are a few of such features.

Handling huge power loads : Marine gears are designed to sustain massive power loads required by the warships. They can handle power as high as 50,000 kilowatts.
Low-weight requirements : In marine gear applications one major criteria is for low weight, but , without any compromising on factors like stability, smooth running, capability and efficiency of the gear transmission.
Power Transmission from twin engines : This feature of having two or more engines is in stark contrast to the non marine gears. Take the case of a luxury yacht or a state-of-the-art warship, mostly marine vessels comprise two or more engines. The use depends on whether they’re in a small harbor or cruising on the open sea.
Resistance to external forces : Gear Box absorbing about 30% of the external forces.
Varying reduction ratios : In cases of big marine vessels, the multiple inputs are primarily the gas turbines, diesel engines or may be electric motors. Based on such combination, the power sources operate at speeds that are different. So the need in Marine Gears is gear trains that has different reduction ratios.
Complex Gear Designs : This a typical feature of marine gears where the gears are designed to fit in the restrictions of space.

Reduction gears for a ship's service turbine generator (SSTG)
Service turbine generator used in ships has the function of converting thermal energy of steam into electrical energy. This energy is used in the entire ship. And to aid in such conversion process a turbine along with a set of reduction gears are used.

Reduction gears brings down the high speed of a turbine to a more usable generator speed. The reduction gears in ships are primarily double helical and single reduction. The double helical design is used for a smooth meshing of the gears. It also neutralizes the chances of axial thrust formed in the reduction gears. This helps in maintaining axial alignment of the gears. The double helical design in reduction gears offers a more effective transfer of torque. As there is just one reduction in speed, they are denoted as single reduction gears.