New lease of life for Alaska ferry

15 Jun 2011
'Klondike Express', revitalised with new MTU engines

'Klondike Express', revitalised with new MTU engines

Vessel designer Incat Crowther says that it is becoming involved in refurbishment of its older designs, bringing them up to latest economic and environmental standards.

The company says that as many of its older craft feature hull forms that are still efficient by present-day standards, repowering and refitting is proving a sensible option. A recent example of this is the refitting and repowering of Klondike Express. Originally launched by Nichols Brothers Boat Builders in 1999, Klondike Express is a 342 passenger 40m catamaran ferry operated by 26 Glacier Tours in Alaska. The vessel was designed as a fast tour boat, featuring a pair of MTU 16V2000 engines and waterjet propulsion. Over the years, the engines and gearboxes became tired, leading to increased running and maintenance costs.

Incat Crowther was approached to investigate a series of renewal options, ranging from low level refurbishment of the existing engines through to the replacement of the engines with alternative brands. Replacement of the shaft line and propulsion system was also considered. Included in the analysis of each option were performance, capital cost, fuel burn, local parts and service availability, and ongoing maintenance costs.

Following a comprehensive study, Incat Crowther recommended that the vessel be re-powered with the latest MTU 16V2000 M63L engines. As well as offering optimum performance and efficiency, there was the additional cost benefit of allowing the existing engine foundation and water jet structure to be retained. This meant the vessel would be out of service for the minimum time.

Part of Incat Crowther’s recommendation was to replace the gearboxes with new units with a revised output ratio. The original ZF BU755 boxes were replaced with current model ZF 7650NR units with a custom ratio. Whilst often avoided from a financial stand point, the custom ratio was beneficial in that it allowed better matching of the jet to the engine output without the need for propulsion changes or major structural work. The new gearboxes were fitted with custom mounting feet, replicating the previous foundations.

Following engine fitting, calibration and trouble shooting, sea trials proved that the results were as predicted, with the bonus of lower noise and vibration levels. Ambient noise on the vessel was reported as being halved, which Incat Crowther says indicates that the main structure remains as strong as ever.

Incat Crowther says it remains busy with similar support and refit work. Among these is a program underway to replace the engines on 45m ferry Mendocino, owned and operated by Golden Gate Ferries.

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