Thursday's fire that gutted the Niu Valley home of famed Polynesian voyaging navigator Nainoa Thompson and his wife, KHON2 television personality Kathy Muneno, was caused by a malfunction of an electric tankless water heater, according to Honolulu Fire Department investigators.

HFD spokesman Capt. Earle Kealoha said today the fire originated in a crawl space under the house at 440 Puamamane St.

Damages were estimated at $300,000 to the structure and $50,000 to the contents.

No one was injured in the fire. The damaged house is one of five structures — four of them homes — on a five-acre Thompson family compound located at the end of Puamamane Street.