Features Technical Time to throttle back
Read more news

Time to throttle back

Fuel prices and a slumping economy have boatbuilders and designers focusing on efficiency instead of horsepower

This Jarvis Newman 30 built by C.W. Hood Yachts has a semidisplacement hull and is powered  to run at planing speeds.If you punched a hole in the fuel tank of a 50-plus-foot sportfisherman, the diesel would gush out slower than the rate at which the engines devour the fuel, says one marine industry veteran.

It’s no secret. Boatbuilders, engine manufacturers — and boaters themselves — know powerboats consume eyebrow-raising amounts of fuel, making them among the least efficient forms of travel. That’s the price we pay. “Only the helicopter may be worse,” says naval architect Lou Codega. “Water is dense, and there’s only so much you can do to move it out of the way.”

Codega outlined some effective strategies to improve mileage and cut down on fuel expenses at a 2007 boatbuilding conference. Build lighter and slower boats, scale back accommodations, and use the latest propulsion technologies. That was Codega’s message.

“Hear, hear,” his colleagues said after the lecture, titled “Moderate Speed Powerboats, Can Less be More?” They praised his philosophy, shook his hand firmly and patted him on the back.

But that was the extent of their response. Virtually nothing changed.

A year later, companies were still building the same wide, commodious planing hulls, weighed down with berths, heads, galleys, gensets, triple-spreader outriggers and a gazillion horsepower.

Full-displacement hulls sacrifice speed for efficiency and a steady ride in a variety of seas.But there are signs things are changing. With fuel prices on the rise again and the economy still slumping, some boatbuilders and designers are realizing they must embrace a different attitude, one that stresses more thoughtful engineering and de-emphasizes speed and horsepower.

“I guess I am in the enviable position of getting to say, ‘I told you so,’ ” says Codega, who for 20 years has been turning out proven designs for the likes of Regulator, Carolina Classic, Hines-Farley and Mirage Manufacturing (Great Harbour trawlers). “Now [changing] is a problem. It’s easier to do this stuff when times are good.”

Will boats become more efficient? Will the public accept or even ask for those changes once the economy turns around? In other words, will it be business as usual or the start of something new? Ken Fickett believes change will prevail.

The design of a typical convertible with inboard power, running along bow high and kicking up a big wake, creates a great deal of form drag because of the deeply immersed transom plowing such a deep furrow in the water.“The days of the stylists designing boats are over,” says Fickett, owner of Mirage Manufacturing, which builds both trawlers and open fishing boats (www.mirage-mfg.com). “I don’t think we can go back to where we were. We need to pay a lot more attention to the engineering that goes into a boat. As we come out of the recession, it’ll be the guys who have done their homework who will rise to the top.”

Even if companies begin to build more fuel-efficient boats, there’s no guarantee that consumers will be interested, says Michael Peters, founder and president of Michael Peters Yacht Design (www.mpyd.net), in Sarasota, Fla. He believes Americans will be hard-pressed to give up their 900-hp, 60-knot vessels.

“These $4 and $5 a gallon [fuel] prices will have to hit us a third and fourth time,” he predicts. “Until then, I don’t think people will change their boating habits or boat companies will turn the corner.”

Case in point is a boat Peters designed in the mid-1980s — a 48-foot ultralight displacement boat with a beam of just 11 feet and a displacement of 14,000 pounds. A pair of 145-hp diesels pushes the boat to 26 knots. “One was built — that was it,” he says.

Peters also believes consumers will be unwilling to accept a boat with Spartan accommodations in the interests of lightening the load and burning less fuel. “To build a lighter, narrower boat you have to give up a hell of a lot of boat,” says Peters, who has designed for Chris-Craft, Cabo and Regal, as well as many custom powerboats.

Unlike Peters, Fickett believes in the if-you-build-it-they-will-come theory, especially given today’s economic and environmental climates. He’s working on a lightweight 40- to 45-foot dayboat that will get an estimated 2 nautical miles per gallon with a pair of 300-hp Volvo Penta IPS pod drives. Codega is designing the vessel.

“We’re going to leave a lot on the beach,” says Codega (www.loucodegana.com), referring to options and amenities. “It’ll be fully cored, long and narrow, but it will be enclosed — sort of like an enclosed express boat.”

Good mileage?

To combat their inherent inefficiency, powerboats must be built lighter, which means more boats with cored construction rather than solid fiberglass and wood structures, according to designers and builders. In a number of applications, new, more efficient propulsion technologies, such as IPS and Cummins MerCruiser Diesel’s Zeus, can be used instead of conventional inboards, though they increase initial cost. The boats must become narrower, not only to cut down on weight but also to allow them to run through the water more efficiently.

All of these elements went into the design, engineering and building of the express boats from mJm Yachts (www.mjmyachts.com), which are known for their efficiency. “You’ve got to think it through,” says Doug Zurn, who designed the company’s 34z and new 40z. “You can’t just throw stuff in a fiberglass shell and hope for the best.”

Zurn says 2,000 hours of engineering went into the 40z (the z is for Zurn). The entire hull and deck are cored, impregnated with epoxy resin in a vacuum-bagging process. Both boats have a waterline-length to waterline-beam ratio of about 3.5 to 1, relatively narrow for an express cruiser. The 40z, with twin IPS500s, gets about 1.5 nmpg at 25 knots. The 34z, with a single 380-hp Yanmar diesel and conventional prop and shaft, gets 2 nmpg at the same speed. In the world of boats, that’s pretty efficient, given the speed. Slow it down more, and things only get better.

This high-performance center console will do over 60 knots with triple 300-hp engines, but don't expect the efficiency and range that you would get with a pair of diesel sterndrives in the same boat. A deep-vee hull like this one, with a moderate beam for the length and a fine entry, will deliver an excellent rough-water ride.Twenty-five knots is fast to some boaters and slow to others. No matter what the speed, you can save fuel by slowing down and finding the boat/engine’s most economical rpm setting — the so-called “sweet spot.”

Capt. Stefan Czuplak skippers a 105-foot Azimut with twin 2,000-hp MTU Detroit diesels. At 20.5 knots, the Azimut burns 159 gallons per hour; at 10 knots it burns 26 gph. “I can burn 4,000 gallons and go 500 miles or go 1,300 miles and burn the same amount of fuel,” going slower, says Czuplak.

The Down East semidisplacement Duffy 31 (www.atlanticboat.com) with a single 380-hp Yanmar diesel consumes 10 gph at 20 knots, or travels 2 nmpg. Back her down to 12 knots, and she burns 3 gph, or 4 nmpg. That’s pretty good mileage for a recreational powerboat.

In contrast, a 33-foot twin 300-hp gasoline inboard express cruiser burns about 30 gph at 29 knots and is lucky to get 1 nmpg. Push that boat to 34 knots, and the burn rate can more than double. A big center console with triple 300-hp 4-strokes traveling at 45 knots consumes more than 100 gph for just more than 0.5 nmpg. You pay a price for speed.

In a recent sea trial, a Viking 50 Convertible at a comfortable cruise of 30 knots consumed 74 gph with its twin 1,360-hp MAN 12-cylinder common-rail diesels. That equates to 0.4 nmpg and a range of 496 nautical miles on her 1,200-gallon fuel capacity. And keep in mind that these numbers were generated during ideal conditions, says Peter Frederiksen, Viking director of communications (www.vikingyachts.com).

“This boat was fresh, with a clean bottom, finely tuned custom propellers, and a reasonable payload of gear, fuel, water, passengers,” he says. “A boat’s speed is connected at the hip not only to horsepower and weight, but also to the conditions, pertaining to the bottom, the depth of water, sea state, fuel quality and various other factors. Also, many boats are improperly propped or are using propellers that are out of pitch, and these factors are extremely detrimental to fuel efficiency.”

Many boat owners — especially those with smaller boats — would do well to put their boats on extreme diets and not carry everything they own when simply out for a day of fishing or cruising.

Operating a boat properly makes a difference, too, says Codega. “I see so many boats running with their bows too far down,” he says. “Pay attention to trim angle. When running in calm water, get as much of the boat out of the water as possible. Bring [the bow] up till it porpoises, and then bring it back down a bit.”

Staying single

Twin engines, of course, bring a slew of benefits to the boating experience, such as redundancy for get-home power if one engine fails and better low-speed maneuverability. Plus, a single engine needs to be pushed harder to achieve the same speed as twins, so power plant longevity factors into the equation.

On the flip side, two engines consume more fuel than one, maintenance and repair costs double, and a twin-screw setup often leaves little access in the engine room.

“In 2002, when I bought a boat with a single engine, people gave me funny looks,” says John Love, who had his Grand Banks 42, Maramor, built with a single 420-hp Caterpillar diesel. “But I think acceptance of single-engine boats is increasing. Part of that is due to the bow thruster and how much it helps.”

Pod-drive technology has softened some of the twin-engine drawbacks, says Love, a Soundings contributing writer whose May 2008 article compares his trawler with the new Zeus-powered Grand Banks 41. “The performance of pod drives is truly a quantum leap over shaft drives,” he wrote. “The smaller footprint of the propulsion machinery and its design enable optimizing its isolation from the accommodations and improving access.”

Both Volvo Penta and Cummins MerCruiser claim that boats with their systems get 20 to 30 percent better mileage than with conventional inboard setups. But the gain in efficiency is often offset by installing larger engines, says Love. “The American market has demanded a ridiculous amount of horsepower and, as a result, lower-horsepower models of these systems are not yet available,” he says.

That demand for ever-increasing horsepower may be waning, some boatbuilders say. Consumers have become more aware of fuel-burn rates, says Bill Sweetland, a salesman at Atlantic Boat Company in Brooklin, Maine, builder of Duffy boats. “A few years ago people hardly ever asked us how much fuel a boat burns,” he says. “Now it’s a consideration.”

Chugging

Darren Plymale, general manager of Galati Yachts in Tampa, Fla., a Tiara, Cruisers and Viking dealer, agrees. Plymale says owners who must run their boats great distances to compete in fishing tournaments, for example, are doing so at slower speeds — 12 to 14 knots — and setting aside more time to reach their destinations. “It’s called chugging,” says Plymale. “Today, it’s not chic to waste money.”

Capt. Brad Wright is a chugger. “Bosses are trying different ways to save money,” he says. “If we save the boss money, we save our jobs.” So instead of running a Viking 74 at 29 knots and burning 142 gallons per hour on a passage from Panama City to Anna Maria, Fla., he chugged at an average of 10 knots and burned only 10 gph. “I was totally blown away at the fuel savings,” says Wright. The trip took him and his four-person crew six days. It would have taken him — and crew of three — only three-and-a-half days at 29 knots, but with a much heftier fuel bill.

It’s not just the big boys looking to save fuel. Doug Logan runs a 26-foot Oldport launch with a semi- enclosed pilothouse and a cuddy cabin with V-berth and portable head. A 96-hp Isuzu diesel powers the semidisplacement boat. “It’s very easily driven and planes at about 9 knots,” says Logan, who is from Stony Creek, Conn. At 12.5 knots, the boat gets

5 nmpg, but in the last couple of years he has been keeping it at 10 knots to conserve fuel. That’s Logan’s version of chugging.

Walter Szeezil of Terra Ceia, Fla., would love to get 5 nmpg, though he’s happy getting about

2 nmpg at 27 knots aboard his Contender 27 deep-vee center console. The sweet spot for his twin 200-hp Yamaha HPDI 2-strokes is 3,200 rpm, and those are the engines that were recommended for that boat on the Contender owners’ online forum. Szeezil had considered repowering with 4-strokes, but he’s now happy he didn’t. “My Contender isn’t designed to handle the extra 250 pounds of twin 4-strokes on the transom,” says Szeezil, who ventures offshore to fish the Gulf of Mexico. “It’s certainly strong enough; the hull just porpoises too much.” Lesson: If you have the choice, pick your power carefully.

Change in mentality

Efficiency isn’t just about spending or saving money. Just because a boat owner is well-off financially does not mean he or she is happy spending ridiculous amounts of money to run the vessel, says Larry Polster, vice president of displacement trawler builder Kadey-Krogen Yachts (www.kadeykrogen.com). “They don’t want to burn 40, 50, 60 gallons per hour,” says Polster.

He points to Kadey-Krogen’s pool of customers. A decade ago, the majority of buyers were sailors; now they account for less than half of the company’s business, he says. “People are moving to us from other powerboats,” says Polster. And fuel efficiency is a big reason why some are moving to a displacement boat. A typical motoryacht, Polster points out, burns seven to eight times the fuel to just go twice as fast as a Kadey-Krogen trawler. The Krogen 44, for example, gets 3.5 nmpg at 7 knots.

Some boaters wouldn’t dream of cruising at

7 knots, but the speed factor can be deceiving and the differences minimized, explains Polster. Think tortoise and hare. “In a trawler, you wake up and get under way,” he says. “The crew can have some breakfast, take a shower, read the paper. You have to do all of those things before getting under way when dealing with a faster planing boat.”

Larry Graf has developed a unique new powerboat that sips fuel and goes faster than 7 or 8 knots. Graf, the former president of Glacier Bay Catamarans, has launched a new company, Aspen Power Catamarans (www.aspenpowercatamarans.com). His open 26-foot prototype is powered with a single 110-hp diesel mounted in the starboard sponson. The shape of the sponson offsets the pulling power of the right-hand propeller to maintain straight tracking. Graf calls it “Hydro-Warp” tracking. The sponson is also 35 percent smaller than the port hull, which cuts down on drag and weight. The result: At 15 knots, the boat gets an estimated 5.6 nmpg, he says.

“I wanted to create something that really fits with today’s time and fuel prices and what people were asking for,” Graf says. “It’s something I think the boating industry needs, and if someone wasn’t doing anything like this, then boating becomes an elite sport. Spending $1,000 to $2,000 on fuel on a weekend is not realistic for a lot of people.”

The first production Aspen power cat is a 28-footer powered by a 150-hp diesel, and it is scheduled for delivery in August, says Graf, whose company is based in Snohomish, Wash.

In the opposite corner of the country, Augusto “Kiko” Villalon has the same goal as Graf, but he plans to get there in a monohull — specifically, a single-screw semidisplacement boat similar to a Maine lobster boat. The boat he envisions is a single-screw 34-footer with a plumb bow and narrow entry, a long keel and a flat bottom. With a 315-hp diesel, it would get around 4 nmpg at 16 knots. “People need to know that if you have [a boat] that does 30 to 40 mph or more you will have large expenditures in fuel,” says Villalon, the founder of Marine Concepts in Cape Coral, Fla., which built the tooling for some of the biggest powerboat brands in the business.

The challenge for today’s boatbuilder is to instill a different philosophy in new boaters, or the “freshmen class,” as Villalon calls them. “We need a freshman class that can still enjoy boating without so much speed,” he says. “[They] have to stop and smell the roses.”

 

See related articles:

- Planing hull efficiency

- The folks who did it first

 

This article originally appeared in the August 2009 issue.

 



BoatQuest

FOLLOW US
fbtwit yt