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Liquefied Natural Gas Powered Boats

Fuel For Thought

Harvey Energy

Does the creation of a fleet of Super-sophisticated, eco-friendly, dual-fuel, LNG-powered platform supply vessels portend a paradigm shift in yacht propulsion? Capt. Bill Pike looks for the answer.

As the primary staging area for oil and gas exploration in the Gulf of Mexico, Port Fourchon, Louisiana, is both a raw, end-of-the-world sort of place and a focal point of modern technology, some of it teetering on the brink of science fiction. As I drove into town one morning a couple of months ago, giant, dinosaur-like tower cranes dotted the landscape, along with jagged-toothed jackup rigs. And a variety of platform supply vessels (PSVs) came and went, plying the canals and bayous that lead off into the Gulf.

Of course, given the low, marshy flatness of the area, I had no trouble finding what I was looking for. The massive, 310-foot Harvey Energy literally towered over everything around Harvey Gulf International’s new Liquefied Natural Gas (LNG) bunkering facility on Gisclair Road, a $25 million extravaganza still under construction at the time, the first of its kind in the United States. Harvey’s security honcho, Dain Detillier, met me at the gate, proffering a hard hat, safety glasses, and a work vest.

“Heah,” he said in an accent that was unmistakably Cajun, albeit most likely high-tech Cajun, given the circumstances. “They’re gonna start fueling LNG in a couple of hours. Captain Pacy’s waitin’ on us, though. He wants to show you around.”

The yard near the dock was abuzz. Two tanker trucks were already parked alongside the Energy. Guys in neon-green hard hats were working at the rear of one of them, connecting insulated hoses while wearing special gray tunics and thick, blue, protective gloves and aprons. Liquefying and transporting natural gas means extremely cold temperatures, often in the decidedly unfriendly neighborhood of -260 degrees F. 

I followed Detillier up a steel gangway to the Energy’s aft deck. As soon as I got there, a guy in a red jumpsuit shoved a clipboard my way—one of several formalities designed to guarantee safety and security. I signed without reading the fine print.

LNG-powered boat

A The capacity of the Harvey Energy’s stainless steel LNG fuel tank is 76,600 gallons. It is double-walled, vacuum-insulated and, when touched, does not even feel cool, despite the -260 degrees F temperature of the fluid inside. Stainless is used for tanks and piping because LNG embrittles other materials.

B To boost lower-deck cargo tank carrying capacities, the three 3,365-horsepower Wärtsilä dual-fuel gensets are located on the main deck, not below. According to Wärtsilä, the gensets operate so cleanly in LNG mode that they already satisfy Tier 4 emissions standards that go into effect in January of 2016.

C The closed-bow design has several practical advantages but the most significant is enlargement of the space that’s devoted to accommodations forward. In addition to 19 climate-controlled staterooms, the Harvey Energy has a gym, sick bay, theatre, conference rooms, and a restaurant-grade galley.

D A fine bow shape below the waterline and a long, narrow underbody promote running efficiency. Top speed for the 310- by 64- by 25.5-foot vessel is 14 knots and cruise speed is 12 knots. At cruise, LNG consumption is 186 gph and diesel consumption is the same. At top end, the vessel burns diesel at a rate of 284 gph and less power-dense LNG at a rate of 393 gph.

Greener Than Green

A couple of years prior to my coming aboard the Energy, during a visit to Trinity Yachts in Gulfport, Mississippi, one of Trinity’s vice presidents at the time, Billy Smith, had offered to show me “a little commercial-type side project” he said might well change the way yachts are built and propelled during the 21st century. Our tour began beneath the six-story, unpainted steel bow of the Energy and finished with her two huge, fully nozzled, LIPS azimuthing propellers dangling over our heads. A giant cylindrical tank on temporary chocks off in the distance beckoned interestingly. The darn thing was easily 100 feet long and about as high as the average ranch house. I asked about it.

“That’s the LNG tank for this baby,” stated Smith, jerking his thumb upwards, “Lockheed Martin’s building ’em for us—you know, the space guys. We’re gonna need six of ’em. For six boats—the first LNG, dual-fuel PSV fleet in the United States.”

Smith went on to extoll the virtues of LNG. He began with emissions—burning LNG in an engine instead of diesel, he explained, cuts nitrogen oxide emissions by 85 percent, eliminates sulfur dioxide (because LNG contains no sulfur), reduces the discharge of carbon dioxide (since LNG contains much less carbon than diesel fuel), and virtually eliminates soot and other particulates. Economics came next—LNG is plentiful in North America, said Smith, and is therefore likely to be much cheaper than diesel in the future. Moreover, it tends to stretch maintenance intervals (particularly for engine cylinder liners and covers), thanks to the exceptionally clean combustion it engenders. And finally Smith bore down on eco-friendliness—all six of the LNG vessels would be owned by Harvey and built and operated to Green Passport and Enviro Plus standards promulgated by the American Bureau of Shipping. These eco-friendly standards would be critical, Smith added, since at least three of the vessels were to be chartered to Royal Dutch Shell, a multi-billion-dollar global enterprise with plans to drill in the Arctic (at press time, drilling had already begun), a spot where minimizing cumulative total emissions (from boats as well as rigs) would be crucial, not only because it would facilitate regulatory compliance but also because it would cut fuel, maintenance, envionmental, and other costs.

“These boats will be greener than green,” Smith concluded. “Which is something that’s increasingly popular on yachts these days. In fact, we’re going to offer an exploration-style LNG yacht based on this PSV design, with plenty of space for tenders, helicopters, water toys, and even an A-frame for subs. We already have a couple of potential customers.”

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This article originally appeared in the November 2015 issue of Power & Motoryacht magazine.