In the absence of survivors, eyewitnesses or wreckage, no one can say with certainty what happened during the final hours aboard the Andrea Gail, other than she disappeared into the cold waters east of Nova Scotia.

But this week, upon the 20th anniversary of the vessel's loss and the so-called Perfect Storm, speculation continues to swirl:

How did the Andrea Gail meet her fate? Did it happen just as portrayed in the movie, when she flipped over trying to conquer an enormous wave? Did anything other than fierce weather contribute to her demise?

Many experts agree that a 72-foot fishing vessel like the Andrea Gail would have little chance surviving the convergence of multiple weather systems now referred to as The Perfect Storm, which included hurricane force winds and wave heights of more than 60 feet.

According to the 1993 U.S. Coast Guard's investigative report, the last communication with the Andrea Gail was on Oct. 28 with another fishing vessel, the Hannah Boden. The report, however, does not reflect the time of the communication.

The Andrea Gail was approximately 150 miles east of Sable Island, presumably heading home to Gloucester — but possibly headed inland for shelter or fuel. It is unknown when or how the fishing vessel lost her radio, or how far she traveled after the radio failed.

"My last conversation with Billy was typical of any that I would have with a vessel 600 miles west of me," said Linda Greenlaw, former captain of the Hannah Boden. "I wanted a weather report, and Billy wanted a fishing report. I recall him saying, 'The weather sucks. You probably won't be fishing tomorrow night.'"

In contrast with the storyline in "The Perfect Storm" movie, Greenlaw says she did not place a distress call on behalf of the Andrea Gail.

"Without a distress call (directly) from the imperiled vessel, the Coast Guard will not initiate a search until the vessel is five days overdue in port," Greenlaw said.

When Greenlaw spoke to Tyne, she said there was no urgency in his voice, and he did not indicate that he was or would be in any danger.

According to the Coast Guard's report, the Andrea Gail was experiencing 30-foot waves and winds from anywhere from 50 to 80 knots around the time of the last communication.

The conditions, though threatening, were probably not unfamiliar to Tyne who had been a successful fisherman for about a decade on other vessels, taking trips to the Grand Banks and fishing off Florida, the Carolinas and elsewhere.

Fisherman Charlie Reed of Gloucester, who stepped down permanently as captain of the Andrea Gail in the summer of 1991, said Tyne had about a year of total experience on the Andrea Gail, and about three months total experience captaining her, before he set out on his last trip in late September.

In Greenlaw's opinion, as the Andrea Gail made her way home, the storm formed overhead and there was little or no warning of the magnitude of what was to come. Predicting the storm also had meteorologists scrambling, with three weather systems on track to collide in the skies above the North Atlantic.

In his book, Sebastian Junger calls the conditions that Tyne must have experienced as a "shear change, like stepping into a room." Junger wrote that the dramatic change in weather happened after 7 p.m.

In "The Perfect Storm" film, Tyne and his crew essentially vote to head into the dangerous storm in order to save their fish from spoiling. Greenlaw acknowledged that Tyne did mention having ice problems, but that was not unusual.

"My one gripe about "The Perfect Storm" movie was how Warner Brothers depicted Billy Tyne and his crew as making a very conscious decision to steam into a storm that they knew was dangerous," said Greenlaw. "That is not what happened. The Andrea Gail was three days into their steam home when the storm hit. Whatever happened to the Andrea Gail happened very quickly."

The crew of the Andrea Gail never placed a distress call or activated an emergency signal.

Because no one knows the details of what happened to the Andrea Gail after her last communication, producers of "The Perfect Storm" movie counted on the expertise and experience of people such as Richard Haworth, who captained the Andrea Gail from 1978 to 1986. Haworth, 58, of Rockport, served as a script consultant on the movie, suggesting possible scenarios to the movie makers.

"I have my own theory," Haworth said. "The Andrea Gail was always a wet vessel; she took a lot of water on deck. Once fully loaded with fuel, water and fish, she was very low to the water.

"When she was modified," he continued, "the owner added weather siding on the port side. My theory is that water became trapped on deck partly because of the additional siding. In rough waves, with the boat rocking from side to side, the accumulating water on deck heaved the vessel to one side and toppled it."

In 1987, the Andrea Gail was retrofitted at the St. Augustine Trawler's Shipyard in Florida. The vessel was lengthened by 30 inches at the stern, or back, to allow for more fuel storage.

As Haworth noted, the portside wall was extended 3 feet with additional siding. Lastly, the whaleback deck (the deck underneath and behind the pilot house) was lengthened by 4 feet to shelter to the main deck.

Water accumulating on the deck after modifications to the Andrea Gail was not the only scenario raised.

The vessel's general stability was questioned in the Coast Guard investigative report.

"Contributing to the casualty may also be the fact that a stability review was not conducted after the modifications made to the vessel in 1987," it stated.

At the time of the Coast Guard's investigation of the incident, the owner of the Andrea Gail, Robert Brown, could not confirm if stability testing was performed after modifications. It should be noted that in 1987, and currently, stability testing is not required on fishing vessels of less than 79 feet, according to Ted Harrington of the U.S. Coast Guard offices in Boston.

"It is good marine practice to have a stability analysis done for any vessel that undergoes a major modification," Harrington said. "Most insurance companies will require a stability analysis to ensure the vessel is good, but there is no regulatory mandate to do so."

Harrington noted that Brown was eventually given a warning, but not a monetary fine, for failure to report his modifications to the Coast Guard documentation office. Harrington considered the lack of updated documentation to be an administrative matter, not a criminal one. Brown has since passed away.

Other theories are still being debated across Gloucester, especially in places like the Crow's Nest, where a fisherman never runs out of tales.

One such fisherman is Jack Flaherty, 64, with over 40 years experience on the sea. Flaherty once worked on an identical sister ship to the Andrea Gail, constructed by the same builder.

Flaherty's theory is that the Andrea Gail may have been low on fuel or had its fuel "muddied" in the rough waters. According to Flaherty, violent movement of the boat can slosh up fuel — bringing up sediment, rust, or algae. Air could also become trapped in the fuel, leading to a stalled engine or complete engine failure.

Flaherty says that in extreme conditions when the waves may be only seconds apart captains have to "jog the waves" — facing the bow into the waves to show the storm the narrowest part of the boat.

"You're going up the face of a 50-foot sea, and then dropping 50 feet into the trough. Seconds later you're climbing another 50 feet and slamming down," said Flaherty. "If your filters get clogged or there's air in your fuel, you could end up powerless in the water. Without power even for a short time, the Andrea Gail could have ended up 'side-to' a wave and been easily rolled."

According to Flaherty, even if the Andrea Gail had almost full fuel tanks, the amount of violent movement may have affected her fuel efficiency and engine performance.

"It's hard to believe it's been 20 years," Flaherty said.

"We can only guess what happened on the Andrea Gail," he said, "but it does us all good to remember and talk about the friends we've lost — not only the crew from the Andrea Gail, but all the fishermen who haven't come home from the sea."

David Sullivan