Fuller’s Fast Cat Korora Provides First Aluminium Hull Reference For Thordon Seal

April 24, 2017

Fullers Group’s has provided a first reference for Thordon Bearings’ TG100 seal on an aluminum hulled fast ferry.

The New Zealand ferry operator’s new 34.9m (114.5 ft.) catamaran Korora, delivered from the Q-West shipyard in December, features a water lubricated propeller shaft arrangement based around a Henley Integrated Propulsion System.

Auckland-headquartered Henley Group, an approved Thordon distributor, with a history dating to 1917, secured the contract to design and supply Korora’s complete drivetrain, following the company’s involvement with the first vessel in the series, the 2014-delivered Te Kotuku.

Mark Power, Managing Director, Henley Group, explained: “Our brief was to design and supply the entire driveline and added the TG100 seal to our Integrated Propulsion System (IPS). At the start of any project we designate ThordonBearings equipment with Henley components as we find they offer greater cost and performance advantages when used in conjunction with our glass-reinforced polymer shaft. They are also much easier to adapt to our Easi Flow sterntube system.”

For first-of-class Te Kotuku, however, the owner opted for a different transmission and sealing arrangement to the one Henley had originally specified; but “after some issues with the first vessel we were asked to supply our complete IPS package, which included Thordon’s TG100 forward seal,” said Power.

In addition to the TG100, Thordon’s scope of supply included SXL tail shaft, strut and rudder bearings along with its ThorPlas-Blue bearing, which was used as an “isolator” between the bronze seal’s housing and the aluminum hull. This arrangement was considered the optimum solution for preventing corrosion.

Henley’s IPS typically consists of its own Easi Flow GRP sterntube and composite shaft, a Henley SS rudder and Tiger propeller, together with Thordon bearings and seals, Twin Disc transmission and engine controls and Vulkan couplings.

“We often find a holistic view is needed from the outset with small to medium-sized projects, since an atomistic  approach can lead to problems once the vessel is operational. We fully understand the connection between engine, transmission, coupling and drivelinecomponents andhave the in-house and supplier knowledge to provide the correct result giving unmatched local andoffshore support during design, build andon-going working environment,” said Power.

George Morrison, Thordon Bearings’ Regional Manager, Western Europe/Africa/ANZ, added: The success of this project, the first installation of a TG100 seal to an aluminium fast cat, opens a new and important market for Thordon Bearings. The fast ferry market is experiencing considerable growth as older tonnage is being renewed and replaced with more energy and environmentally-efficient technologies. We are seeing an increase in enquiries from ferry operators, particularly in the southern hemisphere, for our water lubricated tailshaft bearing systems as way of optimising operations.”

Thordon Bearings introduced the TG100 mechanical seal in 2013. Suitable for propeller shaft diameters of 100mm (4”) to 305mm (12”), the seal combines hard wearing silicon carbide seal faces with Thordon’s proprietary elastomeric polymer bellows.

A unique feature of the TG100 is the emergency seal that permits stand-alone operation to allow the vessel to safely return to the nearest port, preventing permanent seal damage. The unique omega “Ω” shape of the proprietary elastomeric bellows minimises torsional vibration and maintains the required spring force throughout the allowable range of axial shaft movement. This elastomeric bellows has no shelf life and no scheduled replacement.

Korora, the sistership to the 2014-delileverd Te Kotuku, has now commenced operations ferrying up to 400 passengers on Fullers’ Waiheke Island service.

A second vessel, again built to an Incat Crowther design by Wanganui-based Q-West and based on the same Henley/Thordon drivetrain, is schedule for delivery in June. Options are available for an additional two of the same, as part of Fuller Group’s extensive fleet renewal programme.

Koraraprincipal particulars

Designer:                   InCat Crowther
Builder:                      Q-West
Passengers:              401
Length:                      34.9m
Engines:                    Twin Cummins QSK50-M, rated 1800hpat 1970rpm.
Transmission:          Twin Disc MGX 6848 SC 2.37:1
Shaft:                        4indiameter
Propellers:                45in x 52in diameter 5B Henley Tiger fixed pitch propellers
Service speed:        28kt at 85% MCR
Max speed:               30.5kt



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