Hawaii ? Loaded with people paying a discount fare of just $5, the $95 million Hawaii Superferry made its maiden run Sunday with a rushed launch for a three-hour voyage to Maui – the first passenger ferry service between the islands.

Legal problems threatened to beach the giant catamaran like one of the whales that environmentalists fear it will run over, so the company moved up the debut by two days.

More than 500 passengers and crew and 150 cars were aboard when the four-deck, blue-and-white vessel emblazoned with manta rays pulled away from the dock to a chorus of cheers.

Before Sunday, the only way to travel among the Hawaiian Islands was with highly competitive local airlines now engaged in a fare war.

The launch, originally set for Tuesday with fares 10 times that much, was moved up after the Hawaii Supreme Court ruled unanimously Thursday that the state should have required an environmental review before the Superferry started service. Three environmental groups have sued, concerned that the vessel could collide with humpback whales, spread invasive species and create long traffic delays.