Fishermen's News - The Advocate for the Commercial Fisherman

Advances in Fishing Vessel Propulsion


When they were looking at ways to bring the hydraulics inboard, NAMJet found that the one-piece scoop bucket was ideally suited to electric actuation. Photo courtesy of NAMJet.

There are still fishing boats being built under tier 3 regulations, and the possibility of a few more exists in the form of keels laid at shipyards, including Nichols Bros. in Freeland, Washington and the Hansen Boat Co. in Everett, Washington, that still qualify for tier 3 engines.

Tier 3-compliant engines of 800 HP or less can be installed until 2017, but otherwise, tier 4 is here to stay, and with it the drawbacks of increased federal regulation tempered by the benefits of technological advances.

One such advance is the gasoline engine. Although companies such as MAN and Sulzer were producing marine diesel engines in the early 1900s, gasoline was the fuel of choice for modern fishing vessels until the end of the First World War. In the 1920s, diesel engines from Enterprise, Atlas and Fairbanks Morse began to supplant gasoline engines because of their safety, efficiency and lower fuel costs. In the 1930s the GM Detroit Diesel engine division introduced the 71 series of two stroke, high-speed diesel engines, in one to six cylinders. The 71 and later 53 series became industry standard for decades before the engines were retired in 1995.

The company's newest offering for the fishing fleet is a gasoline-fueled engine.

Back to the Future

As automotive engine technology has advanced to meet economy, emissions and longevity requirements, marine engine applications have benefitted from advancements in the automotive sector. One of the most notable advancements in engine control since electronic fuel injection is direct gasoline fuel injection, wherein fuel is injected directly into the combustion chamber. GM Marine Technology is reintroducing gasoline to the commercial sector with the advent of a line of direct fuel injection engines from 4.3 to 6.2 liters.

GM says the main advantage of this technology is fuel savings, with direct Injected engines typically offering 8 to 14 percent fuel savings over port fuel injection engines, while the 6.2-liter engine can develop up to 400 HP, and provide 200 HP at 2600 RPM, burning 5 gallons per hour.

Clean Six

German diesel manufacturer MAN, credited with the first marine diesel installation in 1902, has introduced a new in line six cylinder engine for commercial and pleasure applications requiring EPA Tier 3 certification.

The i6-730 is the latest development by MAN introduced into the US marine market, based on the D2676 line of European diesel engines.

The new 12.8-liter six provides 730 HP at 2,300 RPM, keeping it just below the tier 4 threshold, and incorporates all the latest advances in diesel engine gas exchange and fuel injection technology with modern electronic diesel controls.

With a reduction in NOx of 20 percent and a 40 percent reduction in particulates, the engine meets the tier 3 standards without exhaust gas recirculation or aftertreatment. The engine also makes use of a common rail injection system – controlled electronically – to manage combustion across the entire range of operational speeds.

The introduction of the i6-730 rounds out the US line of MAN engines from 730 to 1,900 HP, and can be sourced at the German company's distributor, RDI Marine, in Seattle.

Marinized Diesels

Along with the distribution of MAN Marine Diesel engines, RDI Marine has announced a partnership with Le Teste, France-based Nanni Diesel. One of the premier engine marinizing companies in the world, Nanni uses robust and reliable base engines from Kubota, Toyota and John Deere and offers a full range of marine diesel engines from 10 Hp to 760 Hp and marine generators from 3.5 Kw to 500 Kw.

All engines are delivered with a special Nanni marinization package including a unique cooling system makes the engines more compact than the original base versions and allows for easier installation. Most engines are available with optional keel cooling. Founded in Italy in 1952, the company moved their manufacturing plant to France in 1991. Nanni is a long time partner of Kubota and Toyota in the marine business and recently signed an agreement with Toyota to become their exclusive engine marinization outlet. In 2014 Nanni Diesel also formed a new partnership with John Deere for the marinization and sale of their 5,6,9 and 13 liter engines.

"Adding Nanni to our existing range of MAN Marine diesel engines is a perfect fit for us," says Brian Cook, owner of RDI Marine.

"Now we can offer our clients the highest quality engines available in the market today from 10 HP to 1,900 HP."

Propulsion Control

All that horsepower won't do you any good if you can't apply it. To address the propulsion needs of hard working fishing boats, NAMJet, LLC, a manufacturer of high thrust waterjet propulsion systems, has introduced a waterjet line that provides an option for electric actuation that eliminates the need for hydraulic pumps, oil tanks, filters, plumbing, ongoing hydraulic maintenance and potential oil leaks.

Ian Ramsay, president of Colorado-based NAMJet, says the secret to the new RaptorJet drives is their axial impellers, offering large amounts of thrust.

A high-speed boat, such as a passenger vessel, will want a high pressure and low flow to achieve high top speeds, using a radial impeller, with relatively narrow flow channels. For high flow at low pressure, an axial flow impeller offers a larger flow area at lower speeds.

To appeal to offshore oil and gas operations, which require inboard hydraulics, the company was considering bringing the hydraulic cylinders inboard, but found that the NAMJet one-piece scoop bucket was ideally suited to electric actuation.

"The actuators are all sealed internally in the boat," Ramsay says, "and easily accessible for engine room." This keeps the sensitive parts away from floating debris, and protects the electronics from corrosive seawater. "There are actually very few moving parts," Ramsay says.

Unlike the tight tolerance of high-speed impellers, the axial, low-flow impellers have substantial tip clearance and can operate in abrasive water conditions. "Because it's built for load rather than speed," Ramsay says, "There's hardly any cavitation."

The new 12.8-liter six from MAN provides 730 HP at 2,300 RPM, and incorporates the latest advances in gas exchange and fuel injection technology with modern electronic diesel controls. Photo courtesy of RDI.

The company's newly built 10-meter (32-foot) demonstrator workboat, Raptor, is fitted with a pair of RaptorJet RJ431e drives mated to a pair of Cummins 6.7L engines providing 480 HP and achieving 40 knots, with a bollard pull of 5 short tons.

"Raptor achieved 39 knots at altitude in fresh water," Ramsay says. "We expect it will do 42 knots at sea level, and have a bollard pull of at least 4.2 metric tons, which is massive."

The company has also introduced a line of Intelligent Navigation & Control integrated electronic control systems, iNAV, which can be configured from a basic system to control engine throttles, transmission, jet bucket and steering up to the sophisticated iNAV-iN5 system providing an intuitive user interface for navigation and full vessel control on a touch screen glass helm. The control features station keeping and dynamic positioning capability, as well as multi-vessel positioning control from a single vessel.


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