A tour boat nearly identical to the one that capsized here, killing 20 elderly tourists, became unstable after weight equivalent to just 10 people was placed at the edge of the vessel, the National Transportation Safety Board (search) said Wednesday evening.

Wednesday's stability test found the Ethan Allen unsuited to handle the weight of the 48 adults who were aboard, said Mark Rosenker, acting chairman of the NTSB. He would not say how many passengers the boat could have safely held.

During the test of the Ethan Allen's sister vessel, the de Champlain, investigators placed three 55-gallon barrels at the boat's edge, then filled them with water, at which point the boat became unstable. The combined weight of the barrels was just over 1,400 pounds, or the equivalent of 10 adults as defined by Coast Guard (search) weight standards.

"We terminated the test because it was unsafe at that point," Rosenker said.

Wednesday's test was the first step toward recreating conditions on this Adirondack lake that might have caused the Ethan Allen (search) to capsize Sunday.

NTSB officials believe the weight and distribution of the 47 passengers in the boat may have contributed to the accident. Both the Ethan Allen and the de Champlain are owned by Shoreline Cruises (search).

NTSB investigators continued to examine the Ethan Allen, which was hauled from the lake Monday, and may put it back in the water for tests.

The Ethan Allen was just shy of its 50-person capacity when it overturned, but that limit was based on a decades-old standard that assumes an average weight of 140 pounds for everyone on board.

Late Wednesday, Rep. John Sweeney, R-N.Y., urged the Coast Guard to speed up its review process for changing the outdated weight calculations.

Sweeney's letter to the Coast Guard came after The Associated Press reported Tuesday that the Coast Guard awarded a contract just days before the Lake George accident to study the effect of raising the average weight estimate. The Coast Guard also acknowledged it had been concerned about the issue since last year.

Investigators also are looking at modifications made to the boat that may have made it heavier, including a wood-Fiberglas canopy that replaced a canvas model, a bigger engine and ballast to keep the boat level.

Investigators were awaiting results of an alcohol test on the Ethan Allen's captain, Richard Paris, 74, the only crew member aboard the 38-foot boat when it overturned.

Paris voluntarily provided a urine sample Tuesday at the NTSB's request, Warren County Sheriff Larry Cleveland said. Investigators did not have reasonable cause to test Paris immediately after the accident because he showed no signs of impairment during an interview, Cleveland said.

The urine test can detect alcohol consumed days earlier. Paris has told investigators his last drink before the accident was a beer the previous Thursday.

Gov. George Pataki said Wednesday that he will soon propose legislation to make the state's boating-safety standards as tough as existing federal regulations. He said he's specifically looking at the federal requirement for testing a pilot for alcohol and drug use after a fatal crash.

The passengers aboard the Ethan Allen were senior citizens from Michigan and Ohio who had come East to see the fall foliage.

All 20 victims drowned, Tim Murphy, a Warren County coroner, said Wednesday.

Glens Falls Hospital, where all 27 surviving passengers were taken, discharged the last three Wednesday morning.