HONOLULU -- The Hawaii Coast Guard is investigating a freak accident that killed a teenage boy and injured several people Friday afternoon.

The Na Hoku Two, a tour catamaran was about a half mile off shore of Diamond Head when fire rescue crews said the mast snapped and broke.

"It was really rough water, but the winds died down and we turned around and came back. It was smooth but the mast it just crumbled there were wires going across our faces and stuff," said Christian Bode, a witness and passenger.

The mast fell to the ship floor, pinning the teenage boy beneath. The crew and passengers attempted to lift the mast off the boy, but it was simply too heavy.

"When I looked back up there was somebody pinned underneath the mast -- it was folded in two or three places there was a call for all men to help lift," said Bode.

The boy and those most seriously injured were airlifted to hospitals. And several others were taken by ambulance.

The boy was pronounced dead at Queen's Medical Center.

Authorities have not positively identified his date of birth, but said he is either 13 or 14.

There was reportedly no warning that the mast would break. Captain John Savio said he had never seen anything like it during his 40 years of sailing.