In theory, interisland travel via ferry ought to be a no-brainer for Hawaii — being able to move through the island chain by sea seems a logical alternative to flying.

In practice, however, a ferry service here must clear major obstacles — including cost and environmental concerns — which, in part, is why none currently exists. Still, the federal government is putting up $500,000 for a feasibility study, which would determine whether a ferry system will provide a viable travel option for Hawaii.

Conducting such a review is well-intentioned, but unless the state can turn the tide with respect to community opposition, the study will merely be an exercise in futility. Even state Department of Transportation (DOT) Director Ford Fuchigami admits there’s that chance: “If the feasibility (study) come back and says … the community’s not going to support it, we’re just going to walk away from it.”

Much is at stake so a thorough review is needed. The $500,000 commitment from the U.S. Maritime Administration is in addition to the $50,000 that state lawmakers approved this year for the DOT to study the possibility of re-establishing a ferry system. The state envisions the project as a state-owned system that could qualify for federal subsidies.

That would be vastly different from Hawaii’s dip into interisland ferry service in 2007, when the private Superferry service launched with two ships. That process, however, was fraught with missteps, including the lack of a full environmental review.

Protesters on surfboards and canoes blocked the Superferry’s entrance to Kauai’s Nawiliwili Harbor and lawsuits slowed the project’s progression. Ultimately, the Hawaii Supreme Court’s environmental ruling on the state’s flawed approvals process effectively drove the company into bankruptcy in 2009. And that was a shame for many residents and visitors who enjoyed the ease of interisland travel via walking or driving aboard the Superferry.

Any new effort would have to include an environmental review that addresses invasive species control — specifically the movement of invasive species between islands — which environmentalists have argued warrants a complete environmental impact study (EIS).

Again, buy-in from environmentalists and community members will be a significant hurdle to clear, and that can only be achieved through open communication and an extensive review process. For this go-round, skipping steps will only result in the same doomed outcome.

The Senate bill directing the DOT to look into re-establishing a ferry system also tasks the department with studying successful ferry systems, including those in Washington state and Alaska. But those operations are in much different environments with calmer waters.

There are also lessons to be learned from Honolulu’s attempt to establish an intra-island ferry system in 2007 that ran between Kalaeloa and Aloha Tower during former Mayor Mufi Hannemann’s administration. The city ditched the effort in 2009; that ferry ran at about 30 percent of its 149-passenger capacity and passengers complained of bumpy rides.

It’s commendable that the DOT has secured the federal funds to study the feasibility of a future ferry service. But consider this the calmest part of this rebooted journey. If the study concludes that a ferry service in Hawaii is workable, taxpayers will need to brace for rougher waters — over financing and environment, for example — that surely will make it difficult to keep the project on course.