Reduction gearbox for ships
(dual input - single output) A Friedr Flender

Actually, marine twin input/single output gearboxes perform different jobs:

They concentrate the power of two or more diesel engines on one propeller
Different speeds of the vessel owing to single input/single output or twin input/single output operation (twin-screw vessels with four engines offer still more flexibility, e.g. during maintenance work on the engines)
Redundant propulsion systems



Frequently, advantage is taken of this flexibility in case of passenger liners, such as ferry boats. PTOs are standard. Frequently, also so-called primary PTOs are provided, i.e. the multiple disk clutches which are fitted on principle for connecting and disconnecting an engine are arranged in such a way, that the PTO can be operated when the engine is running, while the propeller is switched off.

Furthermore, two-speed PTOs are used more and more often, thus achieving still higher propulsion flexibility.

For a cruise liner drive, a twin input/single output gearbox was flexibly mounted in order to ensure that only low structure-borne noise is emitted to the hull.



The largest sailing ship of the world,
the Royal Clipper, was equipped with
two double reduction gearboxes of
the type GVA 1120.

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