SMOKE ON THE WATER

Real jet boats, which use turbine engines, can make you feel like you're flying across the water

BY MARSHALL BRODIE

 

There are jet boats and then there are jet boats. The more common jet boats use a normal piston engine to spin a pump that produces a high pressure stream of water for thrust.

But some boats have real jet engines (more correctly called turbine engines), like those found in helicopters and turboprop airplanes.

I recently drove a 50-foot Nor-Tech catamaran that was powered by twin 1,450-hp turbines from Turbine marine of Pompano Beach, and found that turbines offer many practical advantages, especially for the performance boater.

While John Arruda, president of Turbine marine, admits turbines are not for everyone, he is quick to espouse their benefits of reliability, simplicity, lightweight and ability to use cheaper fuels.

The engines that Turbine marine uses are surplus Lycoming T-53 turbines taken from the military's Huey helicopters. the Lycoming T-53s have an output shaft that can drive a propeller, or in the case of our test boat, Mercury Racing No. 6 Speed-master stern drives. turbine Marine dismantles each engine, restores it to factory specs and modifies it for corrosion resistance in a hostile marine environment.

These modifications include replacing certain parts with aluminum or stainless steel, coating them with chrome or epoxy.

Because an engine failure in an airplane is clearly not a good thing, turbines are extremely reliable. Arruda said a high-performance piston engine of comparable power will have a service life of only a few hundred hours before it needs a total rebuild, which can be as much as $20,000. Turbines, on the other hand have a life expectancy of as much as 50 times longer - or 10,000 hours.

Turbines do burn about 15 percent more fuel at cruising or higher speeds but this is more than offset by the cheaper cost of fuels they can use. Diesel, kerosene, jet fuel or even a 75 percent diesel/25 percent gas mixture are all suitable for turbines. A competition piston engine requires more expensive high-octane pump or race fuel.

However, at idle speeds, a turbine can burn about 40 percent more fuel than a piston engine, making it then more expensive to run.

I had expected the turbines to be temperamental and difficult to learn how to operate. Instead, they are nearly as simple as operating normal gas engines. Arruda says that was one of their top priorities - making the turbines easy to run and use.

STARTING IS SIMPLE

Starting is quick and simple with the flip of a few toggle switches. The throttles, gear shifts and gauges are very much like a typical piston engine with a few additions, including an exhaust-gas temperature gauge and a compressor brake.

Starting the turbines causes the familiar jet engine whine that immediately draws the attention of everyone in the marina. The turbines, though are quiet enough to carry on a conversation without difficulty.

Turbine marine has developed a water-cooled exhaust system that significantly reduces noise and exhaust temperature to only 125 degrees. without the water-cooled exhaust, large amounts of insulation would be needed to shield the fiberglass boat from the heat.

EXHAUST TUBES

Instead, the Turbine Marine's highly polished, stainless-steel exhaust system make for a clean and neat installation without bulky insulation. The exhaust tubes are a large - 15 inches in diameter - making a turbine powered boat instantly recognizable even when it's not running.

Arruda maneuvered the Nor-Tech 50 around the Miami Beach Marina on our way out and proved that it is every bit as easy to handle as a big piston-powered catamaran. Turbine marine does the complete installation of the engine, gauges, controls and rigging in the owners boat.

The Nor-Tech 50 catamaran is an ultra high-performance offshore boat popular on the racing circuit and on poker runs. It is easy to handle and a smooth-riding boat, even at speeds of 100 mph. This turbine-powered Nor-tech though, is actually capable of much higher speeds but, with six passengers on board and a crowded sea of weekend boaters, prudence dictated that we go no faster than the 111 mph that we did - and briefly.

The engines run extremely smooth and without vibration. The high-pitch whine of the turbines at sea evokes a broad smile - it feels like you are literally flying on the water.

PRICEY CHOICE

So why, with some of the turbine advantages, are theory not more common? Simply, turbines are expensive. Yet not exorbitantly so when compared to other ultra high-performance engines.

Arruda said prices start at about $150,000 for each turbine and that includes installation. Most boats have twins so figure on $300,000. If you calculate the long-run costs - the cost per horsepower, the time between rebuilds and the cost of fuel - a turbine is actually cheaper, says Arruda Add in the ego factor of having something unusual and faster than most others and there should be plenty of speed boaters willing to plunk down the money.

Certainly, twin turbines are not for all boats. Arruda's company mostly installs them in high-performance boats in the 45 to 55 foot range.

 

 

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