Coral Princess gets a repower

Operating a 35-metre passenger ship through some of the most environmentally pristine waters on the planet brings with it massive responsibility. So when the engines aboard Coral Princess were due for replacement, the environmental footprint was just as important as the performance data.

Coral Princess is a nature-based cruise vessel operating eco and expedition cruises of up to seven nights on the Great Barrier Reef, 10-night expeditions on Western Australia’s remarkable Kimberley Coast and 11-night Cape York and Arnhem Land expeditions in the waters between Cairns and Darwin. The vessel is part of the Coral Princess Cruises fleet, a pioneer of small ship cruising in Australia and the South Pacific and a leader in its field for almost 30 years. Coral Princess Cruises also offers award-winning expeditions further afield throughout the island archipelagos of the South Pacific, Papua New Guinea, Indonesia and New Zealand.

The Coral Princess was purpose-built for company founder and Managing Director Tony Briggs in 1988. Typically, the Coral Princess logs up some 3000 engine hours each year. After 24 years of service, with a few major engine re-builds along the way, it was time for a complete repower of the ship in line with the company’s best-practice environmental policies.

The Coral Princess is a ‘big’ small ship, displacing 730 tonnes with 27 cabins for passengers plus a crew of 12.

"I have never previously owned a Yanmar engine," said Tony Briggs. "I had worked on them years ago, and I asked around the industry and liked what I was hearing about the brand."

The Yanmar marine diesel engine selected by Coral Princess Cruises was the Yanmar 6AYM-WET. This is a six in-line cylinder engine with a displacement of 20.39 litres and a continuous rated power output of 755mhp (555kW) at 1840rpm. Engine weight (without the gearbox) is 2365kg.

The Yanmar 6AY offers strong performance, low fuel consumption and low emissions. The versatile 6AY Series is extensively used in many examples of heavy displacement work boats but also is quickly gaining an excellent service history and reputation in many high-speed applications such as passenger ferries, patrol craft and cray fishing boats.

The Coral Princess catamaran design facilitated the installation of two of the Yanmar 6AYM-WET engines, one in each hull. Two ZF 2350 Series Island mounted 4:1 ratio transmissions, complete with electronic controls with multiple helm stations were also installed and were mated to the existing propeller shafts.

"Quite apart from the convenience offered, and the increase of engine room space facilitated by the in-line six-cylinder design compared to the original V-12 engines that were removed, we were attracted also to the simple uncomplicated service regime and extended service intervals of 500 hours," said Tony Briggs.

Vibration reduction was a key objective for Coral Princess Cruises when this repower study was undertaken by Power Equipment’s Townsville based Nth Qld Area Manager Nick Marsden.

The final result has seen noise and vibration levels significantly reduced from the original installation, something that has been greatly appreciated by both the crew and passengers alike.

"Previously it was common practise to run the vessel at reduced engine speeds whenever our guests were in the dining room above the engine rooms but now we have no such restrictions," Tony Briggs said.

"The crew also have commented that their quarters directly behind the engine room are much more liveable since the refit. We have achieved supplementary benefits in addition to our prime objective of higher reliability and lower emissions," Briggs said.

"All up I’m very happy with the decision to repower with the Yanmar commercial marine diesel engines."