The Pride of Baltimore, which sank last month off the coast of Puerto Rico, was unstable and prone to tipping and filling up with water, according to an independent study conducted for the Coast Guard two years ago.

Of the 30 sailing ships examined in the study, only two were found less stable. Those two ships -- the Marquez, a British vessel, and the Albatross, an American ship -- both had already capsized and sunk by the time the study report was issued.

According to a copy of the study, which is on file at Coast Guard headquarters in the District of Columbia, the Pride would rapidly lose its stability once it tipped more than about 30 degrees from upright. The ship would begin to flood once it tipped 53 degrees, the study said, and would not be able to right itself once it reached 76 degrees.

Most modern yachts are designed to survive knockdowns of 90 degrees or more. Many of the other sailing ships in the 30-ship study could tip more than 120 degrees and still right themselves. Others were deemed more stable than the Pride because they had smaller masts and more ballast, and so were much less likely to tip over.

The Pride, a 90-foot replica of an early 1800s Baltimore clipper, was struck by an unexpected blast of hurricane-force wind while sailing 280 miles north of Puerto Rico on May 14. The ship was knocked over on its side within 20 seconds, according to its crew, and filled with water and sank within two minutes. Eight crew members survived, but the captain and three other crew members were lost.

The captain, Armin E. Elsaesser III, was aware of the study -- conducted by a Maine naval architecture firm, Woodin and Marean -- and made several moves to ease the problem, including removing heavy excess material, before leaving Europe to sail back to Baltimore. Elsaesser had several long conversations with the study's authors, according to several people who knew him and were familiar with the study.

Two months before the Pride sank, he wrote Pride officials in Baltimore that he was "still concerned about Pride's stability" and wanted to have the ship examined this summer by the naval architects who had written the study. That letter has been presented as evidence in a Coast Guard inquiry into the Pride's sinking.

"It's readily apparent to me that the Pride of Baltimore -- even with only a paid crew on board -- should never have sailed offshore with that rig," said William Peterson, one of the few modern naval architects who has studied sailing-ship safety and who examined the Pride's stability characteristics. He said the Pride was so dangerous that it should have been fitted with watertight compartments to slow sinking, and that additional safety measures should have been taken.

If the Pride's operators were aware of how unstable their ship was, he said, "I am very confident it would have influenced their decision-making, maybe to the point where they would not have taken the vessel offshore."

Gail Shawe, executive director of the nonprofit organization that operated the Pride for the city, said that although the group's officials and sailors knew the ship had drawbacks, they were not worried about its stability. The sailors, she said, were interested in knowing as much as possible about its stability.

"Everybody who sailed on the Pride, especially the captains, were very definitely aware of the fact that this was a 19th century vessel, and that caution was necessary, and that knowledge was necessary," Shawe said. "That's a far cry from being very concerned in the sense of being worried about the safety of the ship."

The Pride was designed by Annapolis naval architect Thomas C. Gillmer, a former U.S. Naval Academy professor who has written a textbook on stability.

In an interview, Gillmer said he did not dispute the Coast Guard study and said he discussed it with Pride officials. But he added, "I'm positive stability was not a factor in her loss." He said he is convinced that the Pride was struck by "a freakish, unusual" blast of wind. "If she had been five miles away she would be with us today," he said.

Gillmer said he designed the Pride with deep ballasting using dense metals to make her as stable as a Baltimore clipper could be. "She was what she was," he said, "and I was under contract to design an authentic Baltimore clipper."

Like the ship's builder, Melbourne Smith, Gillmer testified during the Coast Guard hearings last week that he believed the Pride was fit to put to sea.

He said there were concerns that the ship's center of gravity had shifted upward -- theoretically making the ship less stable -- since it was launched in 1977, and before it sailed to Europe he recommended that excess weight be removed from the ship and that its upper sails and spars, or pieces of wood holding the sails, be removed.

Gillmer said in the interview that the ship's captains believed the ship sailed better with the topmasts still on, and that he trusted their wisdom.

Pride officials testified that much excess weight, such as excess anchor chain, was removed before the Pride set sail. More excess equipment, including about 2,000 pounds of Baltimore promotional material, was removed before the Pride left Spain for the return trip across the Atlantic.

However, the topmasts were not removed. Although the upper masts were not carrying sails when the Pride went down, several experts said the upper masts would have added significant weight and vulnerability to the wind high above the ship, where it could cause the most harm.

Steve Wedlock, the captain of a Massachusetts schooner and a friend of Elsaesser, said the Pride's captain was well aware of his ship's stability characteristics, but "approached the whole thing from a very academic side," rather than with fear.

"Sure, you could have had a more stable boat," Wedlock added. "But you wouldn't have had Pride. You wouldn't have had what Baltimore was trying to do. There's a lot of trade-offs, and I know Armin knew about them, and was interested in them." Whether those trade-offs were too risky, Wedlock said, "is one of those questions you can toss back and forth, and we probably will for a long time."

Coast Guard officials said they plan to thoroughly analyze Pride's stability, using computers, and repeat the tests done by the architects who conducted the Coast Guard study, specifically accounting for the sails the Pride had up at the time it sank.

Several people familiar with the study and with the building of the Pride 10 years ago in Baltimore's Inner Harbor said the accident was forseeable and preventable, not only in the way the Pride was sailed but also in the ship's construction.

Two people who helped build the Pride said workers at the Inner Harbor boatyard made macabre jokes about the "inherent instability" of Baltimore clippers but no measure was taken to alter the design, to install greater ballast to keep it upright, to build watertight compartments to prevent or slow the rate of sinking, or to provide other safety features.

Baltimore clippers were designed as fast, light warships and privateers. Compared to most ships of their length, they were lighter and lower in the water, yet carried masts and sails that were much larger. While it gave the ships speed that could be crucial in battle, it also made them much more vulnerable to high winds and high seas.

"I strongly suspect that a large number were lost in exactly the same way" as the Pride, said Steve E. Bunker, a former merchant marine captain and marine historian who worked on the Pride during its construction and was the ship's official historian.

"What bothers me most is that we had history to fall back on, and the folks that were most involved in the early stages -- people like Smith and myself and Tom Gillmer -- were all historians. We know why these vessels failed, we know what we can avoid. We didn't avoid it . . . . This is a vessel we knew very well was a dangerous ship when it went to sea."

Nick Benton, a professional sailing ship rigger who was hired to construct the Pride's masts and other rigging when it was built 10 years ago, said, "The city may not have realized that accuracy and authenticity was so radically in conflict with the safe operation of the vessel."

He said people constructing the Pride 10 years ago in Baltimore's Inner Harbor frequently made jokes about its "inherent instability," frequently referring to accounts of a Baltimore clipper that capsized and sank while resting at anchor in Charleston Harbor.