A man was killed and two other people injured yesterday when the mast of a catamaran broke during a sunset whale-watching cruise in waters off West Maui.

The 5:09 p.m. accident occurred aboard the 55-foot catamaran Kiele V, owned by the Hyatt Regency Maui Resort and Spa.

Mahina Martin, spokeswoman for Maui County, said the man who died was 48 years old. Two other people were taken in stable condition to Maui Memorial Hospital with injuries that weren't life-threatening, Martin said.

Passengers and crew had to abandon the vessel, which sank.

The Coast Guard said three people were treated for hypothermia.

The identity of the man killed was being withheld until his family is notified, Martin said.

Two other catamarans on whale-watching cruises off Kahana Beach near Ka'anapali — Teralani III and Gemini — responded to Kiele V's radio call for assistance and arrived on the scene ahead of the Coast Guard and Maui Fire Rescue.

Fifty people, which included four crew members and the two injured passengers, were taken to shore.

"When we got there, the (Kiele V) captain and crew were trying to cut away the rigging lines so the sail could get away," said Jason Moore, staff photographer for Maui No Ka Oi Magazine, who was aboard the Teralani III, the first ship to arrive and offer assistance to Kiele V.

"The back side (of the Kiele V) was being pulled down and the captain only had a hacksaw to cut the rigging," Moore said.

Coast Guard Lt. John Titchen said, "It's a terrible tragedy when a case results in a loss of life and our hearts go out to the family of the deceased."

Titchen added: "We are fortunate to have been able to safely bring the survivors to shore, and we were able to do so with the help of the Maui Fire Department and a Good Samaritan. It's a classic example of mariners quickly answering a call for help."

The 399-foot ice breaker Polar Sea, which was tied to a mooring ball off Lahaina, launched a small vessel and responded quickly to the Kiele V's call for help, Titchen said.

Hyatt Regency Maui management could not be reached for comment last night.

Yesterday's incident was the second death aboard a Hawai'i tour catamaran in less than four months. On Dec. 1, 2006, 13-year-old Jordan James Loser of Riverside, Calif., was killed when the 65-foot mast of the tour catamaran Na Hoku II snapped in brisk winds off Waikiki, pinning him.

Reach Rod Ohira at rohira@honoluluadvertiser.com.