VW on the water

It may be branded Cummins MerCruiser, but the 3.0-litre turbodiesel V6 powering Tristram Boats' 851 Grandeur model is pure Volkswagen.

The V6 is just one of three Volkswagen engines Cummins MerCruiser Diesel (CMD) is selling under the name TDI, for marine applications.

And just like the cars powered by Volkswagen diesels, the boats fitted with them are earning plaudits from all over. Introduced at the Auckland International Boat Show back in March, the range of diesel engines — a 1.9-litre four-cylinder, a 4.2-litre twin-turbo V8 and the V6 already mentioned — are naturally intended for sterndrive vessels with the engines mounted inboard.

Lance Fink, the owner of Tristram Boats, based in Hamilton New Zealand, drives an Audi Q7 with the same basic engine CMDs offer in V8 form for power on the water. Fink, impressed by the performance of his Q7 with the 4.2-litre V8 was ready and willing to try the V6 for his company's 851 Grandeur, a 9.1m trailerable cruiser that has won seven Boat of the Year Awards to date.

“We were very, very impressed by the performance – good things do come in small packages,” Fink said. “We’re talking about a three tonne boat. To have a top speed of 40.4 knots (75 km/h) with a V6 3.0-litre engine is quite outstanding. At 1600 revs if you weren’t holding on you were thrown out the back of the boat – the pick up was that good.”

The VW-powered boat will reach 24km/h on the water in three seconds, with 48km/h coming up in eight. It's not in the same league as the speeds achieved on land with the same engine, but the difference in kerb mass alone is something like a full tonne in favour of the car, with the traction advantage going to the car also.

The engine lends itself very well to work on the water, says Fink.

“It’s a lightweight, compact engine so it’s easy to install and because it’s a common rail diesel there was no fuming and no smell,” he said. “During the test we were using 25 litres an hour at 50 kilometres an hour, so why would you bother with a V8 petrol engine? You wouldn’t, because that would be using 48 litres an hour.”

The 1.9 is available in different states of tune, ranging from 40 to 75hp and weighing 200kg, is suitable for sail-drive configuration also. At 325kg, the compact V6 can be tuned for 225 to 265hp and the twin-turbo V8 weighs little more, at 368kg, but produces 350hp and 700Nm.

CMD sells the TDI engines in Australia as well as New Zealand and the South Pacific.

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