Just before the early morning accident that claimed the lives of four crewmen aboard the towboat Elizabeth M on Jan. 9, 2005, dam gates at the Montgomery Lock and Dam were raised, speeding up the high water and dangerous currents the towboat and its six heavy, coal-laden barges unsuccessfully tried to navigate as they exited the lock chamber.

A U.S. Coast Guard investigation report dated May 1, 2006, but never publicly released, states, "While the Elizabeth M was in the lock chamber, the dam gates were raised from 83 feet to 89 feet. An increase in the flow rate over the dam would have increased the outdraft current at the upper approach to the lock."

That's where the Elizabeth M, working on the already storm-swollen Ohio River, lost control of its barges and, while trying to corral them, was washed over the dam and sank. Drowned in the worst river accident in the Pittsburgh area in four decades were Edward Crevda, 22, of West Brownsville; Scott Stewart, 36, of Wheeling, W.Va.; Tom Fisher, 25, of Latrobe, and Rick Conklin, 40, of Crucible, Greene County, whose body was recovered from the engine room of the towboat during its salvage almost two months after the accident.

Coast Guard report documents also disclose for the first time that the master of the Elizabeth M, George Zappone, and the pilot of another towboat, the Richard C, assigned as a "helper" on the tow, were issued "letters of warning" for failure to follow river navigation rules and specific sailing orders, and that Mr. Zappone was guilty of "misconduct." The names of the Richard C master and pilot were redacted, or blacked out, of the report.

The new information about the accident investigation and the U.S. Army Corps of Engineers' operation of the dam 32 miles down the Ohio River from Pittsburgh, near Industry, Beaver County, is contained in one of several Coast Guard investigation documents obtained through a federal Freedom of Information Act request by the Pittsburgh Post-Gazette.

Stephen Moschetta is an attorney whose Washington, Pa., firm specializes in marine cases and settled a claim for Mr. Conklin's estate against the owner of the Elizabeth M, Campbell Transportation. He didn't know the dam gates were opened while the tow was in the lock chamber and said the action may have contributed to the accident.

"It's surprising. It created a greater chance that what's in the lock chamber would be pushed out toward the middle of the river," he said. "Whether it's negligence I don't know, but it didn't help. It could have been an aggravating factor."

Karen Auer, a spokeswoman for the Corps of Engineers, said opening the dam gates could have affected the outdraft, but not as much in high water as when the river is at normal flow.

"It's possible it could have increased the outdraft currents," Ms. Auer said. "It may have had some slight effect but not as much as at lower water levels."

She said an internal Corps review found that standard procedures were followed on the night of the accident and all lock and dam personnel acted properly. Lock and dam workers were interviewed by Coast Guard investigators but none was sanctioned or penalized in any way.

Ms. Auer said it is not standard procedure to notify boats in the lock chamber that the dam gates have been raised or lowered, even when the river is flowing swiftly at high levels, and the Elizabeth M was not notified. That procedure has not been changed as a result of the accident.

"Sometimes when tows are approaching the lock they will ask and we will tell them," she said, "but it's not routine." She didn't know if the Elizabeth M requested that information.

Coast Guard Commander Steve Wischmann, the officer in charge of the Coast Guard's Marine Safety Unit in Pittsburgh, called the opening of the dam gates "useful information," but said it is just a piece of the evidence considered by investigators. He said the final case report, which he expects to be completed soon, will make "a number of conclusions" about the cause of the accident.

"I'm very concerned about maritime safety, and sensitive and aware of this accident," said Mr. Wischmann, who was not stationed in Pittsburgh when the accident occurred. "We'll take whatever steps necessary to reduce the likelihood of this type of casualty from occurring in the future."

The report documents released to the Post-Gazette by the Coast Guard said the towboat Richard C was headed downriver between the Montgomery Dam and Georgetown, pushing an empty barge scheduled for repair work, when it passed the Elizabeth M with its six-barge tow traveling upriver.

Mr. Zappone and the pilot of the Richard C disregarded their written orders for both boats to get in tow together despite the high water conditions. The report states that the pilot of the Richard C, whose name was redacted, or blacked out, should have contacted Campbell Transportation to inform the company of the Elizabeth M's disregard for the written orders.

The Richard C pilot was issued a letter of warning by the Coast Guard "for his lack of action in this case, which may have prevented this incident if he had acted on the written orders from Campbell Transportation for the vessels to meet in Georgetown."

In addition, Campbell Transportation Inc., owner of both towboats, was criticized in another of the investigative documents for sending "inadequate" sailing orders to the two boats. The document stated that the wording of the orders faxed to the two vessels was unclear and that the company did not allow adequate time for the Richard C to travel downriver to Georgetown, five miles below the Montgomery Dam, to meet the Elizabeth M where it built its six-barge tow.

Campbell Transportation was also fined $6,000 for discharge of fuel oil from the sinking of the towboat.

Chuck Minton, Campbell Transportation president, declined comment until the Coast Guard releases its full and final report.

The Elizabeth M was already fighting high water and a heavy current early on that cold Sunday morning when Mr. Zappone completed his six-hour shift and turned over the boat to its pilot, Mr. Stewart, who maneuvered the tow into the lock chamber. The lockage was completed without incident and lock workers described it to Coast Guard investigators as a "picture-perfect lock."

Mr. Conklin, a "striker-pilot" or provisional pilot in training, took over from Mr. Stewart and was at the controls of the Elizabeth M when the tow began exiting the lock chamber, according to the narrative in a 31-page incident report. The towboat pushed the six barges approximately 200 feet out of the lock chamber before releasing the tow and maneuvering behind the stern.

"This is the approximate time and location where the effects of the outdraft [current] would have been felt at the head of the tow," the report states. "The tow was out of shape and being set toward the center of the river by the outdraft."

As they exited the lock chamber, the front barges collided with the upriver "bull nose" at the end of the middle lock wall. The collision caused all but one of the ropes tying the front two barges to the rest of the tow to break away as the towboat continued to push the other four barges out of the lock chamber.

At that time, approximately 2:08 a.m., Mr. Zappone returned to the pilot house, took control of the towboat from Mr. Conklin and attempted to maneuver the tow upriver to mooring cells located above the upper end of the landside lock wall.

When that didn't work, and as the barges drifted in the strong current toward the middle of the river and the dam, Mr. Zappone moved the Elizabeth M from the port side of the tow around to the starboard side where a line was tied to a timberhead on the middle barge. By that time, around 2:18 a.m., the tow had drifted inside a dangerous restricted area above the dam.

Mr. Zappone attempted to back the barges upriver with the Elizabeth M's engines running in reverse to pull instead of push the barges, but was unable to make any headway against the current.

Orders were given to release the tow, which quickly collided with the dam. Three barges went over the dam and three were caught in the dam at gate 3 and sank.

The Elizabeth M struck the dam sideways, at a 45-degree angle on the starboard side, then spun and went over the dam stern first through the gate 6 spillway. Before it started going over the gate "rollers" at approximately 2:20 a.m., a locksman told Coast Guard investigators that "the whole stern was completely submerged, and the rest of the quarter deck and so forth went very fast, and the only part I could physically see was the wheelhouse."

The investigative report's executive summary states, "Actions taken by the Master [Mr. Zappone] before and during the casualty did not adhere to written policy/procedures."

Five of 10 investigative report documents on the towboat accident remain classified as "still under investigation" by the Coast Guard, now part of the U.S. Department of Homeland Security, 34 months after the accident, and therefore were judged not eligible for release.