HONOLULU -- The second of the city's two commuter ferries broke down on Monday and was unable to transport passengers on the first day of a week of free service.

The two catamarans, known as TheBoat, will make three morning trips and three afternoon trips between Kalaeloa and Aloha Tower. Commuters can hop on board the city's ferry service and any of five bus lines.

The second ferry that was supposed to take passengers from Kalaeloa at 6 a.m. had ignition problems and could not make the trip, according to officials.

The city offered 35 people planning to take the ferry an Express Bus instead. Eighteen riders took them up on it.

The problems disappointed the mayor.

"As much as I don't want to see it happen, it did. We just have to fix the problem and put it out there again and hope that more people will not use this as a reason not to use the boat," Mayor Mufi Hannemann said.

A private contractor is running the ferry demonstration project for a year, costing federal taxpayers $5 million. The city is spending another $1 million on buses coordinated with ferry arrivals and departures.

The mayor said he expected problems at the beginning.

"I'd rather have it happen now. I'd rather err on the side of caution as opposed to these things happening after six months we've been in operation. At that point, it would be inexcusable," Hannemann said.

So far, the ferry has averaged 55 passengers per trip, according to city officials.

The ferry pilot project is heavily subsidized by taxpayers at about $52 per passenger per round trip, KITV learned.

"It's going to take time for people to get adjusted to this, and there's a certain percentage of people that will never ride a boat, obviously, because of seasickness, motion and so forth," the mayor said.

City officials hope the service will help reduce traffic congestion.