A $90 million catamaran designed to provide Hawai'i's first interisland ferry service in more than 25 years hit the water for the first time yesterday, the latest step in what officials say is an on-schedule plan to begin operations here in July.

The 350-foot, still unnamed vessel was eased from a Mobile, Ala., shipyard construction area into a floating dock, then released into free-flowing waters, company officials said in Honolulu.

"It was a monumentous moment," said Hawaii Superferry chief executive officer John Garibaldi, coining a new word in his excitement.

The vessel still faces months of sea trials in Alabama, a long trans-Pacific journey, more trials in Hawaiian waters and stiff environmental, legal and legislative opposition. But for a time yesterday, company officials swept all that aside to revel in a day they said had been years in the making.

"We're still prepared to start our operations as planned July 1," Garibaldi said. "We are extremely excited to present an important travel alternative."

Opponents, concerned about the ferry's impact on the environment and overcrowded Neighbor Island harbors, said yesterday they'll work to delay the start-up date of ferry operations, citing a pending lawsuit and a move at the state Legislature to require the company to do a lengthy environmental impact study before proceeding.

State Sen. J. Kalani English, D-6th (E. Maui, Moloka'i, Lana'i), the chairman of the Senate Transportation and International Affairs Committee, and other Neighbor Island legislators have said they'll try to delay ferry operations until the study is done.

"A lot of people want to know what the impact will be on the environment and traffic. A full study would go a long way to making them more comfortable about those things," English said.

Yesterday's launching at the Austal shipyards in Alabama drew crowds of workers and onlookers eager to get their first full view of the ship that will carry up to 866 passengers and 282 vehicles, company officials said.

With structural work on the ferry complete, crews will now turn to finishing the interior and starting sea trials. The company plans to take possession of the ship in March.

If all goes as planned, the ferry will arrive in Hawai'i waters sometime in early May and be ready for its first passenger run two months later. Initially, the company plans to offer daily roundtrip service between Honolulu and Maui and Kaua'i, with one-way passenger fares ranging from $42 to $50. When a second ship joins the fleet in 2009, the company will expand service to the Big Island.

The company has met and overcome all the major obstacles since investors first began thinking about a new interisland ferry service in 2001, Garibaldi said. The obstacles included obtaining more than $200 million in private financing and government loan guarantees, and $40 million in state-funded ferry improvements to Hawai'i harbors, and dealing with widespread concern about the ferry's potential environmental impact, including the possibilities of interisland transport of invasive species and of collisions with migratory humpback whales.

"We continue to work with the community to address all the environmental concerns," he said.

Critics, however, believe the company has not gone far enough.

City councils on Maui, Kaua'i and the Big Island have passed non-binding resolutions calling for a more complete environmental study, and a state judge on Maui ruled last month that a lawsuit by Maui County and two groups seeking to block the ferry can proceed. The suit contends that the state's current master plan for Kahului Harbor is inadequate given the entry of the ferry. Noting that the planned start of the ferry is just months away, Judge Joel August urged the parties in the lawsuit to negotiate a settlement.

Interim state transportation director Barry Fukunaga said yesterday that talks aimed at a settlement are under way. "We've been in contact with the plaintiffs and are trying to come to a meeting of the minds," he said.

State officials expect to have all barges and ramps necessary for ferry operations in place by the ship's arrival in May, Fukunaga said. The state is also reviewing the latest Superferry operations plan, which includes a blueprint to control traffic and other potential problems.

"They've submitted the plan and it's being assessed. We're going back and forth on details with them now, but as of now there aren't any major obstacles," he said.

Superferry officials yesterday also unveiled a new manta-ray-looking logo for the ferry and announced a partnership with the Big Island Manta Pacific Research Foundation, whose mission is to study rays in their natural habitat, conduct scientific research and provide public education about mantas, including a display that will be on board the ferry.

Reach Mike Leidemann at mleidemann@honoluluadvertiser.com.