Cat gets an extra life

A fresh pair of Yanmar 6BY2-260 engines has given a new lease of life to a KevlaCat 3000 Sportfisher in Fremantle. Event Horizon has been transformed with the extra Yanmar power delivering unsurpassed reliability for game fishing trips off the coast of Western Australia.

The owner of Event Horizon, John Gardner is an avid offshore fisherman. His favourite fishing grounds lie 50nm off the coast of Denham, an isolated coastal town some 850 km north of Perth. Regular trips into the Indian Ocean, fishing around Bernier Island and Dorre Island, demands that a reliable and utterly dependable pair of engines are on board.

When Gardner approached Fremantle Yanmar dealer Stem 2 Stern about a repower, his boat had one damaged engine that had been flooded. Andrew Wright (pictured) at Stem 2 Stern quickly understood the predicament and recommended that a fresh pair of Yanmar 6BY2-260 engines form the basis of the re-power.

The Yanmar 6BY2-260 is a six-cylinder marine diesel engine which is rated at 260hp (191kW) at 4000 rpm. This is produced from a 2.993-litre, intercooled and turbocharged in-line six-cylinder block. All up weight of the Yanmar engine is just 315kgs.

Yanmar says the second-generation common-rail direct-injection technology, featuring magnetic vertical injectors, ensures optimum performance and outstanding fuel efficiency.

Stem 2 Stern commenced the repower program by removing the 212hp six-cylinder diesel engines which were fitted to the KevlaCat when originally built. The original MerCruiser stern drives were also removed and set aside.

To achieve correct hull balance with the new and more powerful Yanmar 6BY2-260 engines, each engine was fitted into the engine bay some 400mm forward of the old engine position. The compact installation envelope of the Yanmars ensured that they slotted into the tight confines of the respective engine bay in each sponson.

The re-power program proved to be the ideal opportunity to make some changes requested by Gardner. The fuel tank capacity was substantially increased by 150 litres per side, giving Event Horizon a range now of 500nm.

The batteries were repositioned from the bow to the engine room, a modified exhaust system was installed to reduce back pressure, bilge blowers were installed and the old MerCruiser drives were replaced with a pair of fresh MerCruiser Bravo 2 X legs running a 1.81:1 ratio.

Event Horizon is a very large trailer boat, measuring 9.3m loa with a beam of 2.8m. It weighs in at four tonnes. Tyhe owner enjoys week-long live-aboard game fishing trips on his boat so the big fuel capacity, solar panels and high demand on electrical power are all important considerations.

With the repower completed, sea trials confirmed that the decision to re-power with Yanmar was well founded. With an extra 90hp beating away on board, Event Horizon is a new cat with an energetic performance at sea.

"Following the change of engines, new sterndrives with different gearing and the balance of the hull adjusted, we have undertaken extensive prop testing to ensure that the engines operate at their optimum 4000rpm," said Andrew Wright.

Top speed has increased from 35 knots at WOT to 41 knots with the Yanmar 6BY2-260 spinning up at 4000rpm. A comfortable cruise speed of 21 knots is achieved at 2400 rpm with fuel consumption measured at 20 litres per hour per engine. With the original engines, 20 knots was achieved at 3200rpm, meaning more fuel was consumed, more noise and more wear.

The re-power project has proven that old boats have plenty of life left in them when modern engines are transplanted into the engine room. The Yanmar 6BY2-260 marine diesel engines deliver more power, greater efficiencies and absolute confidence for the owner and his crew when they head over the horizon to go game fishing.