A 361-pound porbeagle shark was the winning fish in the weekend’s 23rd annual Monster Shark Tournament in Oak Bluffs. The fish was caught by the crew of a Marshfield fishing boat called Karen Jean II. The captain of the vessel was David Dion of Galveston, Tex.; the boat owner was John Anderson of Marshfield and crewman was William Murphy of New Bedford.

Hundreds of spectators gathered along the promenade at Oak Bluffs harbor Saturday afternoon to watch the fishing boats come in and display their catch. Poor weather on Friday limited the two-day tournament to one. There was a report that only 12 fish were weighed in.

The tournament got off to a rocky start when one of the boats sank early Friday morning in 15-foot seas. Four fishermen were rescued from the boat five miles south of South Beach in Edgartown.

The 20-foot Blue Jacket radioed that it was taking on water at 7:36 a.m. Friday. Jordan Baptiste, executive petty officer of the Menemsha Coast Guard Station said the Coast Guard dispatched a 47-foot motor lifeboat upon hearing the report. The call was discontinued when a nearby powerboat, the Sophia, also on hand for the shark tournament, rescued the four men from the water.

Mr. Baptiste said the Blue Jacket was underway off Muskeget Channel when a large wave came over the bow and broke the windshield, swamping the boat. “They then headed for the nearest point of land and another wave came over the vessel’s stern, at which point it started sinking,” he said.

Sophia’s captain, Kosta Tsoleridis, 19, of Centerville, said: “The water was so nasty. It was scary out there.”

Sophia is a 38-foot off-white Pearson

yacht out of Yarmouth. She left the dock at 6 a.m. and was headed toward the Claws, a fishing spot about 12 miles south of the Vineyard. En route, seas became treacherous. “I turned on the weather channel and there was a forecast for gale winds until 10 a.m.,” the young captain said. He said his crew members asked to turn back. Two were seasick below. The trip was called off, and on the way back, Sophia’s captain spotted a man waving a lifejacket in the air on the stern of the half-submerged boat.

“They said they were going down,” Mr. Tsoleridis said. He kept his boat a safe distance from the Blue Jacket. “The captain yelled ‘Wait a minute,’ while he tied down his fishing rods,” Mr. Tsoleridis said. “They jumped into the water and swam for us,” he said, adding:

“The captain of the other boat was the first guy on our boat.”

Mr. Tsoleridis credits the strength of his older brother Lazo, 24, for pulling the swimmers out of the water.

They then took the four swimmers back to Oak Bluffs, where they were met by EMTs but refused medical attention.

Mr. Tsoleridis said he and his crew received no thanks for what they had done and that surprised him. He owns Seaside Painting Company and with his brother works out of Hyannis. On Saturday the weather improved. Mr. Tsoleridis said they caught and released five sharks, mostly blue sharks and one little mako. The biggest blue shark they caught and released was estimated to be 350 pounds.

Mr. Anderson, the winner, said yesterday that he and his crew tried to fish on Friday but turned back because of the high seas. They fished Saturday and caught the winning fish south of the Vineyard. Mr. Anderson, who is 40, said: “The credit goes to the boat and the crew.” He said they used bluefish for chumming and as bait. Karen Jean II is named after his wife. The vessel is a 35-foot Willis Beal R.P. boat. He said he has fished the tournament three times. “It seems the whole event is cursed by bad weather,” he said, adding: “I think the water was pretty cold out there for this time of year.” Mr. Anderson sells radiation detecting equipment for a small family-owned business.

Oak Bluffs harbor master Todd Alexander said participation was down in the shark tournament this year. “It was definitely not as many boats as the year before,” he said.

Mr. Alexander said there were few incidents. “We don’t have any problems with the shark people. We always have issues with the spectator boats,” he said.

A special shark weighing station was set up next to Our Market, where the biggest of the fish were weighed in. Scientists from the National Marine Fisheries Service, and universities including University of Massachusetts at Dartmouth were on hand to collect tissue samples.

Entrants in the contest paid $1,375 or more to compete.