References

For both ocean-going tugs with the hull numbers V-085 and V-086, built at the Spanish shipyard Astilleros Armón for the Heerema shipping company (the Netherlands), VULKAN ESPAÑOLA, a subsidiary of the globally active VULKAN Group, has delivered highly flexible couplings for the main drives, PTO gearboxes and generators.

With the drive concept implemented in these tugs, a total of four Caterpillar MaK engines, type 6M32C with a rated power of 3,000 kW each, drive both propellers, whereby two engines each are synchronised via one gearbox. In the main drive there are a total of four highly flexible RATO DS couplings, one for each shaft, used between the four Caterpillar engines 6M32C and the two Reintjes gearboxes DLG-5551P.

For the gensets of both anchor-handling tugs with Caterpillar engine C-32 (994 bkW at 1,800 rpm) and alternators LSA-50.2 VL10 of Leroy Somer, as well as for the emergency power supplies with the Caterpillar engine C18-ACERT (601 bkW at 1,800 rpm) and Leroy Somer alternators of type LSA-491 S4, VULKAN ESPAÑOLA has delivered a total of eight highly flexible VULASTIK L couplings. In order to meet the system requirements, there are different qualities of rubber available depending on the torque to be transmitted.

The RATO DS of type A-33DZ BR 2200 are highly flexible elastomer couplings that have been specially developed for the main drives of ships with a requirement of high torsional flexibility and medium misalignment capacity. The different available stiffnesses enable a good tuning of the system with respect to both the transient and steady-state torsional vibration response, even for those systems where the performance depends primarily on perfect interaction between the two engines connected to one gearbox - and especially in cases in which one of the both engines is switched on or off. Another advantage of the successful cooperation between VULKAN and the engine manufacturer for the Heerema shipping company: Since no more time-consuming approval processes are necessary, the customer receives a highly reliable drive solution that has been tested many times with the shortest delivery lead time.

The main parts of the VULASTIK L coupling are hub and flanged casing, between these, the disc-shaped element is arranged. This disc element is connected by vulcanization at its inner radius; the outer radius is connected to the flanged casing by a plug-in toothing. This toothing provides the axial plug-in feature and compensation of shaft displacements.

In this application, too, Caterpillar relies on a solution from VULKAN that has been proven many times over. Thanks to the already existing allocation of the different sizes and rubber qualities of the VULASTIK L for the customary combination of engine and generator, the customer is spared the long project-planning phase with cumbersome approval processes. In addition, the shipping yard and shipping company benefit from the fact that all elastomer couplings required for the entire new project come from a single source, leaving synergy effects also to be utilised keeping installation and maintenance in mind.