HONOLULU -- Hawaii's Superferry has docked, indefinitely.

Emotional protests and legal setbacks have plagued the ship since its weekend debut with runs between Honolulu and two of the outer islands.

The Coast Guard said it can't guarantee the 350-foot ferry's safe passage in and out of the harbor at Kauai.

About 65 people on surfboards, canoes and kayaks formed a human blockade Monday and forced the $95 million ferry to turn back to Honolulu.

They are concerned about the ship's impact on the environment.

The governor, a longtime ferry supporter, has requested the service be stopped because of public safety concerns.

It had already been suspended for Maui because of a court challenge by environmentalists. A hearing in that case was set for Tuesday.

Hawaii Superferry Inc. President and CEO John Garibaldi, said operations would not resume until safety was assured, KITV-TV in Honolulu reported.

The company stands to lose millions while its vessel is grounded, but Garibaldi said his company's main concern involves taking care of customers.

Passengers, many of whom paid a discounted $5 rate to ride the ferry, were put in hotels and given vouchers for future travel.

The company also paid for flights, hotel rooms and car rentals for passengers who sailed and were stranded on Kauai.

Some passengers were told they would be flown home now and their vehicles would be shipped back home to them at a later date.

Supporters said the superferry is a viable alternative for travel between the islands. For decades, the only option was through local airlines.

Opponents say the ferry's daily runs between the Hawaiian Islands endangers whales, threatens to spread invasive species and causes pollution.

Superferry officials note that the vessel is jet powered, with no exposed propellers to endanger marine line.