A Maui dive boat yesterday morning came across what appeared to be a 5-foot-long, barnacle encrusted torpedo floating about six miles off shore in the Hawaiian Islands Humpback Whale National Marine Sanctuary. John Ness | Special to The Honolulu Adveriser.

"It was obviously a navigational hazard," said Jeff Strahn, the general manager of Maui Dive Shop. "We've never seen anything like this."

The crew of the 48-foot Maka Koa dive boat came alongside the object floating in calm waters and tossed a bodyboard near it to mark its location, Strahn said. The captain radioed the Coast Guard around 8:15 a.m. and gave the boat's global positioning system coordinates, Strahn said.

A Coast Guard helicopter and a 110-foot cutter searched the waters in the Olowalu region for two-and-a-half hours without finding any signs of the object, Petty Officer 3rd Class Angela Henderson said this morning.

"We got the call around 8:15 and went out there ASAP," Henderson said. "We checked it out but couldn't find anything."

The Coast Guard has turned the investigation over to the Navy, which did not immediately have any information this morning.

The captain of the Maka Koa told Strahn that the object was a 5-foot long "torpedo shaped object with a blunt nose and a halo ring around the tail, where you would have a prop on it," Strahn said. "It had a plate on it but they were unable to read it. They didn't want to put someone in the water next to live ordnance."

John Ness of Seattle saw the object while aboard the Maka Koa and alerted the captain.

"I hollered at the captain to turn the boat," Ness said. "I didn't want him to hit it. We missed the torpedo by 10 feet. ... The disconcerting thing is they didn't find it."

Jeff Walters, co-manager of the 1,400-square-mile Hawaiian Islands Humpback Whale National Marine Sanctuary, said, "It's the first I've ever heard of an actual torpedo being seen in the sanctuary.

"If it's just floating like that, whales don't typically just blindly run into things," Walters said. "They typically have good sight."

But juvenile whales and calves are prone to become curious and play with something in the water, Walters said.

If the object turns out to be live ordnance, Walters said, "there is a remote possibility that something bad could happen if they go up and touch it to see what it is."

The Maka Koa had left Maalaea Harbor around 7 a.m. with a captain, three divemasters and 21 customers onboard for a two-tank dive off of Lana'i, Strahn said.