Yanmar gives more power without penalty

After clocking up 1750 hours on the twin 735hp two stroke diesels installed in his Ocean Alexander when it was built in Taiwan 18 years ago, Richard Wilson decided he need more power to do justice to the hull.

While his engines were a long way from being worn out, Wilson felt they did not provide the power and absolute reliability he sought. So after toying with the idea of buying a larger boat, he decided on a comprehensive refurbishment of his boat, the 15 tonne Synergy.

His research suggested modern diesels could deliver more power with no weight penalty. "I asked around boating friends, professional boaters and marine experts," he says, "There wasn't a single person I spoke to who had a bad word to say about the Yanmar brand."

He ordered a pair of Yanmar 8SY-900M engines, V8s with a displacement of 15.6 litres and electronic unit injectors and electronic engine management. Rated at 900hp at 2300 RPM, the engines weighed just 1650kg without the gearbox.

With an overall length of only 1236mm, the Yanmar 8SY-900Ms slotted neatly into Synergy’s engine room without any modifications to the bulkheads needed.

After two months at the Rivergate Marine and Shipyard in Brisbane, Wilson’s boat emerged with his power up from 736hp per engine to 900hp per engine and lighter by 120kg.

"We can now travel faster and in more comfort," Wilson says, "A wide open throttle we are running 2300RPM for 32 knots, while a comfortable cruise speed is 1800RPM for 22.5 knots." He says his fuel consumption is also less.

"We still have some work to do on the props to achieve better performance but I could not be happier with my choice of Yanmar."