Honolulu fire investigators determined a fire that damaged a shark tour boat in Haleiwa Harbor early this morning was intentionally set.

It’s the second fire involving a North Shore Shark Adventures tour boat this month.

The cabin of the boat was engulfed in flames when firefighters arrived at about 12:11 a.m., said fire Capt. Robert Main.

The fire was extinguished within ten minutes.

The fire damaged the front end and cabin of the boat, which was in its slip. No one was on board the boat and no one was in the area when firefighters arrived, Main said. 

Damage is estimated at $225,000. The investigation is being turned over to police.

Fire investigators said arson caused a fire on a North Shore Shark Adventures boat that destroyed a 30-foot shark tour boat on Jan. 7.

The 12:40 a.m. fire burned the bridge and cabin of the boat and the heat from the fire damaged a nearby vessel.

Damage was also estimated at $225,000.

North Shore Shark Adventures is one of two shark-tour operators operating out of Haleiwa that have been the source of constant debate in recent years.

On Thursday, a District Judge Christopher McKenzie dismissed charges against five current and former shark tour company employees, who were accused of feeding sharks in state waters.

The charges were dismissed after federal officials refused to submit a user’s manual and related materials for a top-secret tracking device also used in terror and drug-trafficking cases.

Defense attorney David Hayakawa said they needed the user’s manual and other key materials are used by the National Oceanic and Atmospheric Administration used to track the location of the shark tour boats.

The tool is at the center of the cases against the men because the charges allege they fed sharks within state waters that end 3 nautical miles off shore.