A 55-year-old Steamship authority crew member is in Providence Hospital, recovering from a near-drowning suffered yesterday when a routine man-overboard drill aboard the Steamship Authority ferry Islander went suddenly and catastrophically wrong.

Barry Brooks was assisting in the drill aboard a 12-foot rescue boat when the boat overturned after it had been lowered from the ferry into the water. His ankle entangled in a line, Mr. Brooks was pulled below the surface and held under by the overturned boat.

Vineyard Haven harbor master Jay Wilbur said the ferry was leaving Vineyard Haven harbor, just outside of the breakwater, when a drill was called by a member of the Coast Guard. Mr. Wilbur said the 200-foot ferry was near the number six buoy. The drill started five minutes after the ferry left the dock at 9:30.

As is the practice, the Coast Guard officer threw a dummy into the water to mark the start of the drill. The 12-foot rescue boat on the port deck of the Islander, an inflatable vessel with an outboard motor, was lowered into the water. Mark LaLiberte, 43, of Worcester and Mr. Brooks climbed into the boat from a door on the freight deck. The boat began taking water over the stern and overturned, trapping Mr. Brooks underneath.

A passenger saw what happened and jumped into the water to help. Farley Doucette, a high school teacher from Forked River, N.J., was finishing up a vacation on the Vineyard and going home. He swam under the overturned boat and extricated Mr. Brooks's leg from the rope.

Meanwhile the Vineyard Haven Yacht Club committee boat Vigilant happened to be in the area, loaded with 19 children from eight to 10 years of age. The youngsters were in a class, not sailing because it was windier than usual that day.

"It happened so quick. I don't remember making the decision. I just knew I had to go," said Mr. Doucette, who years ago worked as a lifeguard.

The Vigilant, a Wasque 32, turned and came up alongside to help.

Mr. Doucette and Mr. LaLiberte were able to get the unconscious Mr. Brooks aboard the Vigilant. Four crew members, college-aged, then brought the boat to Tisbury Wharf.

The tugboat Sirius of Tisbury Towing and Transportation, captained by Paul Bangs, lent assistance. Two boats were also dispatched from Martha's Vineyard Shipyard. Phil Hale said: "There was some confusion as to how many people were in the water, so we sent Titan and Riptide."

Donna Swartwood was standing at Tisbury Wharf at the time. "I saw Vigilant driving full speed toward the dock. It was so unusual to see so many kids on board. They yelled at me to call 911." Noreen Russell, operations manager for Tisbury Wharf, called for an ambulance.

Mrs. Swartwood said: "It was all very quick. There were police and the harbor master. The staff of the Vineyard Haven Yacht Club was incredible. They ran to the street to make sure the ambulance came to the right place. They were great."

Mr. Brooks was transported by ambulance to Martha's Vineyard Hospital. At the time of his departure from the dock, he was reported to be breathing on his own.

Josh Rosenblatt of Easthampton, who photographed part of the rescue from shore, was driving along Beach Road and made two stops to watch what was happening. Mr. Rosenblatt said he first thought something was wrong with the ferry. "I saw a tugboat next to it. The boat seemed to be listing to port. Eventually, the ferry moved out of the harbor. Then I saw an ambulance heading down Beach Road toward the hospital."

From Martha's Vineyard Hospital, Mr. Brooks was later transported to Providence Hospital by a Coast Guard jet. Due to a federal regulation that protects patient privacy, the Martha's Vineyard Hospital was unable to release any information yesterday about Mr. Brooks.

Paula Peters, a spokesman for the Steamship Authority, said Mr. Brooks condition is stable. "Our thoughts and prayers are with Mr. Brooks and his family. We are hoping everything is okay. This is an example of how dedicated these people are. Every day they put themselves in harm's way, to insure safe passage of our passengers. We hope Mr. Brooks comes out of this okay and is back at work soon."

The ferry Islander was delayed only 20 minutes by the incident. The 10:45 a.m. boat from Woods Hole back to the Vineyard was canceled so repairs could be made to the rescue boat.

The cause of the accident remains under investigation, both by the Steamship Authority and by the Coast Guard.