GEMINI: Clean, lean and green: a new ferry for the Bay

To meet low-wake requirements, the hulls of the new ferry are long and unusually narrow; you can stand inside and touch both walls at once. (Brian Gauvin photos)

Only California could come up with specs this tough: Build a new commuter ferry for San Francisco Bay with low shoreline impact, restricted draft, minimal noise, whale-seeking sonar and an emissions level far, far lower than anything else in the United States.

But that is what two yards in the Pacific Northwest have achieved. Nichols Brothers Boat Builders, of Whidbey Island, Wash., and Kvichak Marine Industries, of Seattle, have teamed up to build Gemini, the first of two 118-foot, 149-passenger aluminum catamaran ferries that meet all the environmental mandates heaped on them by the state, including an emissions level at least 85 percent better than EPA Tier-2 2007 standards.

The project was born eight years ago out of traffic gridlock resulting from the dot-com boom. New ferries to get commuters off the roads seemed like a good solution, and the state was willing to put up the money. But in California, the environment comes first. Hence the complexities of the vessel.

At the heart of Gemini’s technological wizardry is a treatment system known as selective catalytic reduction, or SCR, which works a little like a catalytic converter on an automobile. The emissions reduction package, which, fully installed, accounts for about $1 million of the $8 million cost of each ferry, was sold by Pacific Power Products of Kent, Wash., which also supplied the two MTU 16V 2000 diesels. “Right from the get-go we talked to the engine manufacturers,” said Bryan Nichols, vice president for sales and marketing at Nichols Brothers. “We were told, ‘You cannot meet that requirement without SCR.’”

Selective catalytic reduction works by breaking down nitrogen oxides (NOx) with the aid of urea, which is sprayed into the exhaust piping as it leaves the engine. Power plants have used the process for years, but only two vessels in the United States have experimented with it, a Staten Island ferry and M/V Solano, a 300-passenger ferry built in 2004 by Dakota Creek Industries of Anacortes, Wash., and owned by the city of Vallejo, Calif.

Ironing out the bugs

The key to minimizing emissions: Consultant Charlie Walther discusses one of two selective catalytic reduction units that treat exhaust gases after they leave the two MTU 16V 2000 diesels. The piping takes the treated exhaust and releases it from the stacks, eliminating the risk of saltwater corrosion.

In a marine setting, some disadvantages of SCR quickly became apparent, notably crumbling of the brick-style catalyst units due to saltwater intrusion into the exhaust. Charlie Walther, an engineering consultant from San Rafael, Calif., who is acting as the owner’s representative for the customer — the bay area’s Water Emergency Transportation Authority, or WETA — says Gemini addresses all of these problems. The exhaust now comes out of the stack, and the catalyst beds no longer use bricks. As a check, the builders had the dealer bench-test the entire system. “Nichols built the exhaust pipes and we mocked it up with the entire assembly,” said Walther. “We accomplished our objective.”

Despite the novelty of the SCR system, speed was not a major concern for WETA, which was looking for just 25 knots, so the propulsion itself is straightforward. The two MTU diesels, rated at 1,410 hp each at 2,100 rpm, work via ZF 3050 transmissions to turn five-bladed Michigan Wheel propellers with a diameter of 46 inches. However, because of draft restrictions — another environmental mandate — the Incat Crowther design had to be adapted to create a “tunnel” in both hulls, allowing the shipyards to raise the propellers and reduce the overall draft at the propeller tips to 6 feet 2 inches. “A lot of work went into the tunnel to make sure it met the draft requirements,” said Nichols. Instead of trim tabs, the vessel uses adjustable interceptors at the aft end of the tunnels.

Haul the engine? No problem

Bryan Nichols shows off Gemini’s interceptors, which operate instead of trim tabs.

At the insistence of Mary Culnane, WETA’s marine engineering manager and the chief inspiration behind the new boats, another hull change was made to permit engine haulout without drydocking. Each engine slides aft on an I-bar to an opening covered by a soft patch. The forward end of Gemini’s port hull was further modified to attach a somewhat experimental sonar detector for whales, marring the hull’s knife-edge aspect with a protrusion below the waterline.

From an operator’s point of view, the bridge and crew quarters are outstanding. The pilothouse, raised above the upper deck, offers a 360° view, and multiple closed-circuit cameras provide security and assistance with docking and undocking. Port and starboard windows slide open for better visibility, and the console arrangement is clear and spacious. “The most experienced ferryboat operator we know did the layout,” said Walther. “I’ve been involved with about 10 of these high-speed craft and this is the best.”

The interior is luxurious. “In order to get Californians out of BMWs and into a boat I had to make the boat quite nice,” said WETA’s Culnane. There are six types of seating arrangements, ranging from two-abreast, first-class-style seats by the windows, to booths for families and bar stools with high tables. “By the snack bar I have what I call the singles bar,” said Culnane. The seats, by Beurteaux, have a minimum width of 23 inches with at least 25 inches between centers. Each row has 120V outlets for laptop chargers, and the ferry will have free WiFi.

Passengers can enter through side doors from both port and starboard, and WETA wants many of them to travel with bicycles (the bay area is trying to discourage commuters from driving to its ferries). There is storage for 18 bicycles aft and 16 forward and a freshwater rinse. In an emergency, Gemini carries a ramp on the foredeck and can load over the bow.

Nichols Brothers is proud of its craftsmanship; one companionway had a series of picture-perfect welds in the aluminum.

Gemini is scheduled for delivery in December. Its sister vessel, Pisces, is next, followed by two virtually identical 199-passenger ferries; the only significant difference is a reclassification from Subchapter T to Subchap-ter K to allow for the extra load.

Both Nichols and Kvichak have full order books. Nichols, which has bounced back from a nasty brush with bankruptcy last winter that briefly shut it down, is building a series of 100-foot tugs; Kvichak’s projects include a 185-foot yacht hull for Delta Marine, a 54-foot survey boat for NOAA, and an 85-foot debris collector for the U.S. Army Corps of Engineers — plus a multiyear contract with the U.S. Coast Guard to supply 45-foot response boats from its Kent, Wash., plant. Neither yard wanted to tie up its resources in a single long-term project, so the result was a joint venture in which Nichols is the prime contractor for Gemini and Pisces and Kvichak takes over for the next two.

A tale of two yards

Although Nichols was always the original prime, Keith Whittemore, Kvichak’s president, says: “We really never decided who was going to do what until the contract was awarded. [Then] we made the decision that Nichols would take the lead on engineering and we would build the hulls and outfit the hulls and wet deck, put the engines in, put the gensets in, put the machinery in, and then float them and tow them up. In that period of time, they were going to be building the houses and getting all of that ready to go.”

Other than switching the lead role, the two yards will split the rest of the work in exactly the same way. Nichols has already sent updated engineering drawings on to Kvichak. “Even though we had a handshake agreement that we would continue to work together … , we did want to make sure that whoever got the projects, the engineering data wasn’t lost,” said Nichols. “A lot of brain power went into that.”

Gemini represents one of the most unusual engineering challenges in ferries in many years, and WETA played hardball to make sure the designers got it right. There are monetary penalties for not meeting speed requirements or low-wake standards. As for missing the emissions mandate, the penalty is nothing less than rejection of the vessel. Both yards are convinced that won’t happen. “This will be an environmentally clean, quiet, low-wash, shallow boat, there’s no doubt it about it,” said Whittemore. “It will be the most technically advanced boat of this size, certainly in the world at this point.”

By Professional Mariner Staff