Yanmar Re-Powers Angles Day-Charter Boat’s

Dependability is everything in the charter boat business. Mills Charters, (Perth’s leading Charter Company specialising in Deep Sea Fishing, Whale Watching and private function vessel hire) were seeking the ultimate in dependability when they choose to re-power their purpose built vessel, “Blue Strike” with a single Yanmar 6AYM-WGT commercial engine.


“Blue Strike” is a custom built 70ft (21.3m) Conquest built in 1995 specifically for the fishing charter market and currently operating from Hillarys Boat Harbour in Perth. She stands high out of the water and offers unsurpassed levels of comfort and stability. With a displacement of some 30 tonnes, a beam of 5.5m and a licence to carry up to 30 anglers on each day trip she has provided thousands of anglers a day they will never forget.

Like all boats, age eventually caught up with “Blue Strike”. The original V12 European marine diesel engine was due for a rebuild. With an expensive rebuild looming the option to repower with new technology and a comprehensive factory warranty appealed to the owner.The decision to re-power, refurbish and re-fit was made and an off-season window of two months was allocated to take “Blue Strike” out of service. It was an ambitious program with just 4 weeks allocated to the Yanmar re-power aspect.

Following consultation with various marine engineers, propeller suppliers and Power Equipment, the authorised distributor for Yanmar diesel engines, the decision was made to fit a Yanmar 6AYM-WGT. The Yanmar 6AYM-WGT is a six in-line cylinder engine with a displacement of 20.39 litres and a rated power output of 911 hp (670kw) at 1938 rpm. Engine weight (without the gearbox) is 2365 kilograms.

The Yanmar 6AYM-WGT offers strong performance, low fuel consumption and low emissions. The versatile 6AY Series is extensively used in many applications including heavy displacement work boats but also in many high speed applications such as passenger ferries, patrol craft and cray fishing boats. Re-powering the “Blue Strike” was undertaken by Yanmar Dealer, Aquadisiac Marine Services. Business partner Rowan Horch and David Norton-Smith approached the task with a simple process in mind… to completely strip the engine room, install the new Yanmar 6AYM-WGT engine and re-fit new electrics and exhaust system to suit.

“The Yanmar engine and transmission slipped into the engine room relatively easily,” said Rowan Horch. “Most re-powers require modification to the bearers and engine beds, but in this case it all went smoothly. All up the Yanmar is 400 kgs heavier than the old engine and we positioned it slightly further for’ard in the engine room.”

A Yanmar YXH-240 transmission was also installed to complete the power train. The original prop shaft and rudder were re-used but a new prop was fitted, being a 5 blade 39” x 38” unit supplied by M & J Engineering in Fremantle.   Once slipped back into the water, sea trials on “Blue Strike” proved once again, the benefits of re-powering with Yanmar. Compared to the old V12 diesel, the new Yanmar 6AYM-WTG delivered impressive results.

The Yanmar while slightly heavier, delivers an extra 176 mhp to provide a boost in on-water performance; 18.5 knots with the Yanmar compared to 16.5 knots with the old engine.
The staggering aspect to this re-power is that all of the benefits are achieved with a reduction in fuel consumption.


According to Blue Strike’s skipper Anthony Doupain, the benefits of the Yanmar re-power go well beyond the raw performance stats. “The Yanmar has made a big difference to “Blue Strike”, said Anthony Doupain. “It is 10% quieter on board and there is no turbo whistle. With the Yanmar spinning over freely, the hull gets up and planes easily. In a following sea the hull doesn’t bog down and there’s always plenty of power on tap to punch the bow up.”

In terms of service the Yanmar 6AYM-WGT is also a winner. The service interval on the old engine was 250 hours, but the new Yanmar is now double that at 500 hours. The inline 6 cylinder configuration certainly has made servicing and engine room access a lot easier which is also appreciated by the crew. This means that costs are reduced and “Blue Strike” can spend more time at sea with anglers enjoying their day fishing.

Following on from the success of the repower of “Blue Strike’s” Mills Charters recently repowered “Aussie Warrior”, a vessel regarded as the aristocrat of their fleet. The Aussie Warrior which was built by the renowned West Australian boat builder, West Coaster displaces some 35tonnes and at 75ft (22.8m) makes her the biggest fishing charter boat in West Australia.


Again the Yanmar 6AYM-WGT was the engine of choice for the “Aussie Warrior”, a choice that was made somewhat easier for the Mills Charter team by having the performance and fuel economy results of the Yanmar as fitted to “Blue Strike” well documented at the time of their decision making and providing consistencies and economies within their fleet.