San Francisco catamaran ferry runs fast, quiet and shallow

The new San Francisco Bay Water Emergency Transportation Authority (WETA) commuter ferry, Gemini, did nothing to shatter the early morning stillness of Tiburon, a well-to-do bedroom community in Marin County, across the bay from the city. That’s because the vessel was built to run fast, quiet, shallow, and most important, run clean. This is, after all, California.

Gemini (American Ship Review 2008-2009) and fleet-mate, Pisces, are the first of four 118-foot catamaran ferries to join the WETA fleet. They are designed by Incat Crowther of Sydney, Australia, and built by Nichols Brothers Boat Builders of Freeland, Wash., and Kvichak Marine of Seattle.

With the state’s penchant for looking at the past and thinking of the future, more rigorous demands were required of the designer and builders regarding the environment. California is, after all, putting up the money.

Captain Michael Patrick Crehan at the controls of the ferry with a service speed of 25 knots on the 18-minute crossing.

For emissions, the contract demanded 85 percent below the Environmental Protection Agency’s Tier 2 requirements. That figure was exceeded due to the exceptionally strong performance of the selective catalytic reduction (SCR) system employed. The SCR system injects a urea solution into the exhaust between the engine and a catalyst, causing a reaction that breaks down the exhaust to a harmless gas. The catalyst also reduces particulate matter. A stainless steel box aft of the main cabin, housing the urea canisters, gleams in plain view like an altar to ecology.

The ferry landing at Fisherman’s Wharf makes for a dramatic entry into the city.

“The urea system has become the biggest tourist attraction aboard,†said Patrick Murphy, the director of operations for Blue & Gold Fleet, the company that operates the vessels for WETA.

The ferry provides passengers with a relaxing alternative to the Golden Gate Bridge.

Pacific Power Products supplied Gemini with two 1,410-hp MTU diesels. The transmissions are ZF 3050 units turning five-bladed Michigan Wheel propellers. To meet a shallow-draft requirement for operating in the south bay, a tunnel to house the shaft line was built into the underside of each hull. The tunnel is 14 inches deep at the propellers resulting in a hull draft of 5 feet 5 inches.

The knife-edge bows that cut the water and stream it back along unusually narrow hulls along with the propeller tunnels contribute greatly to Gemini’s exceeding the low wake requirements in the contract.

An MTU diesel in each hull provides power.

“The cool thing about her is the saving in fuel,†said Capt. Michael Patrick Crehan. “She uses 30 gallons per hour as opposed to 200 gals per hour for the other boat on the Vallejo run.â€

Gemini operates between San Francisco and Tiburon during peak commuter hours in the morning and afternoon, making each run in the requisite 18 minutes to meet the schedule. However, with the capability of a service speed of 25 knots, Gemini and Pisces are being pressed into backup service on other runs between peak commuter hours.

Deck hands James Norman and Linda Hallford on the aft deck.

“She can replace two of the other boats and be doing the same job,†said Murphy.

Deck hand Rich Phillips, hosing off the salt spray at the San Francisco Ferry Terminal, cited more pragmatic reasons for admiring the vessel.

“The best thing about this boat, I mean she’s a beautiful boat, but the best thing is the vinyl coating. It doesn’t blister or chip like paint on aluminum. The paint just peals and chips off aluminum. It’s the biggest plus.†•

The knife-like bows of the hulls promote speed and fuel efficiency
By Professional Mariner Staff