Bracket adds buoyancy and efficiency

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Armstrong Yanmar Marine bolt-on option for inboards and sterndrives extends a boat’s range


Armstrong Nautical Products, known for its outboard engine brackets, has teamed with Yanmar America Corp. to produce an engine bracket for sterndrives and inboards.

The AYM (Armstrong Yanmar Marine) bolt-on diesel bracket can be used as an alternative to a boat’s current conventional propulsion installation, whether that’s outboard, sterndrive or inboard power.

The AYM brackets, which are fabricated with marine-grade aluminum, also can be installed on factory-built boats. “There will be applications in both the [original equipment manufacturer] and repower markets where the user is needing or wanting diesel durability and economy,” says Rusty Sedlack, vice president of Stuart, Fla.-based Armstrong.

The apparatus holds the entire propulsion package aft of the transom. It’s available with a variety of Yanmar diesel sterndrive packages — from 188 to 370 hp. A Parker 2530 Extended Cabin is the first boat to be outfitted with the bracket. It’s powered with a 260-hp Yanmar 6BY2-260 linked to a Yanmar ZT350 hydraulic clutch sterndrive.

“As it turns out, the Yanmar BY series of engines that we’ve designed the bracket around is very similar in weight to the larger outboards,” Sedlack says.

Among its other benefits, the bracket adds buoyancy to the hull and its location lowers the engine’s center of gravity, says Tom Watson, marine division manager of Adairsville, Ga.-based Yanmar America. And the design creates an unobstructed transom boarding platform, he says.

“There are certain [boat owners] who will light up to this — maybe those who run their boats or cruise a great deal,” Watson says. “It’s not going to be for the light-usage [boater]. It’s going to be for fairly enthusiastic boaters.”

Builders who have expressed interest are those who already use outboard engine brackets and want a diesel offering without having to make an investment in their tooling, Watson says.

Armstrong custom-designs brackets for each particular boat/engine combination.

“We’ve developed a set of questions about the boat and motor that allows us to come up with a solution that will provide the performance efficiencies of the Armstrong bracket for each application,” Sedlack says. “This process is no different for the AYM unit.”

No additional boat construction requirements are necessary for vessels already using Armstrong’s outboard brackets, Sedlack says. The key ingredient: a solid transom in good condition with a minimum thickness of 2-1/2 inches, he says. “If these parameters are met, then anyone should be able to install the bracket — and the entire unit is bolt-on,” Sedlack says.

Performance numbers suggest that Parker has made a wise choice with the AYM bracket. At 26.7 mph, the Yanmar burns 10.8 gallons per hour for a mile-per-gallon rating of 2.5, and it gets the same mileage at its top speed of 34 mph, according to Yanmar testing. In comparison, a Parker 2530 Extended Cabin with twin Yamaha 150-hp 4-strokes (F150 model) at 26.3 mph burns 12.8 gph for a 2.06 mpg rating, according to Yamaha testing. At a top speed of 39.9 mph, the Yamaha-powered Parker can travel 1.44 miles to the gallon, the Yamaha data indicate.


Consumers will appreciate the fuel efficiency of this propulsion option — and that they have the option in the first place, says Linwood Parker, owner of Parker Marine Enterprises Inc. “When gasoline and oil prices are high we are all more sensitive to fuel consumption,” Parker says. “In 2006-07 fuel consumption was important, but it’s nowhere near as sensitive of an issue as it is in today’s world. People are looking for value. Range and longevity of the engine have become a real premium.”

The Parker has a 173-gallon fuel capacity. The AYM-bracketed Parker at its 26.7 mph cruise speed would have a range of 375 miles using 150 gallons; the outboard-powered boat would have a range of 315 miles at its sweet spot of 26.3 mph.

The diesel-powered boat has better range, but diesel power is significantly more expensive. A 25-foot extended-cabin model with twin F150 outboards is about $110,000, compared with $125,000 for the same boat with the diesel setup, Parker says. But the diesel boat’s upfront cost will be worth it for some boaters, Parker says.

The AYM bracket completely encloses the Yanmar diesel. Parker says he was impressed with the Yanmar engine’s noise levels and its acceleration.

“It was quiet and comfortable coming out of the hole and got on plane quickly,” Parker says, adding that the company’s 28-footer is also a candidate for the AYM bracket installation. “It’s a heckuva package. On this boat with its standard fuel placement, [production] was simply a matter of bolting the bracket to the transom. The weight distribution and the trim angle were perfect.”


The bracket extends the running surface at displacement speeds, but not when the boat is on plane, Parker says.

The combined weight of the diesel power and bracket is just about equivalent to the twin-150 installation on the 2530 Extended Cabin from Parker, he says.


Yanmar estimates the weight of the bracket, engine and drive to be 1,400 pounds. (Two Yamaha F150s weigh about 950 pounds, and the Armstrong bracket for the 25-foot Parker Extended Cabin weighs 230 pounds.)

The AYM bracket was shown Oct. 17-19 at the International BoatBuilders’ Exhibition & Conference in Louisville, Ky. Sedlack said in early October that Armstrong and Yanmar did not plan to display the bracket at the Fort Lauderdale International Boat Show in late October and were unsure whether it would be shown Feb. 17-21 at the Miami International Boat Show.


However, Armstrong and Yanmar will enter the bracket in the DAME design awards competition Nov. 15-17 at the Marine Equipment Trade Show in Amsterdam, Sedlack says. Armstrong captured a DAME award two years ago for its boarding ladder for rigid-hull inflatable boats, Sedlack says.

The companies are looking to Europe as a potential market. Yanmar officials in Europe are impressed with the product and think it would do well, and a DAME award can lead to significant media exposure. And Europe, in general, is more inclined toward diesel power than the United States is.

The price of the bracket-engine arrangement will vary according to the power chosen and the ultimate shape of the bracket required, Sedlack says. “Generally, the price is slightly higher than outboards of equal power with a bracket,” he says.

For the Parker 2530 Extended Cabin, the propulsion package — a 260-hp Yanmar 6BY2-260 linked to a Yanmar ZT350 with an AYM bracket — is about $46,000, according to Yanmar.

Armstrong, which also deals in marine ladders and deck plates, has been fabricating outboard brackets for 20 years, Sedlack says. The brackets often are used for repowering projects.

Parker has been building boats since the late 1960s. Today it builds center-console, walkaround and sport cabin (pilothouse) boats. The fleet ranges from 18 to 34 feet.

Yanmar’s U.S. subsidiary was established in 1981. It offers diesel engines from 150 to 900 hp.

Yanmar America recently brought to market a sterndrive package with joystick capability. The joystick is part of Yanmar’s new Vessel Control System, which will be linked to a new diesel — the 8LV — a 4.5-liter twin turbo V-8 available in 320- or 370-hp configurations.

Contacts: Yanmar America, (770) 877-9894,; Armstrong Nautical Products, (772) 286-7204,; Parker Marine Enterprises Inc., (252) 728-5621,

This article originally appeared in the November 2011 issue.


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