HELENA - When Meriwether Lewis first pushed his "great experiment" into the Missouri River near present-day Great Falls in 1805, he surely beamed.
"She lay like a cork," he wrote in his journal.
But the iron-framed boat that Lewis designed floated only for a moment before it leaked and sank, taking with it his high spirits. "The circumstance mortified me not a little," he wrote.
Lewis and expedition co-commander William Clark gave the boat a proper burial in a field near the river's great falls. It was never mentioned again.
But now, archaeologist Ken Karsmizki intends to find it.
Karsmizki, of the Columbia Gorge Discovery Center in The Dalles, Ore., has enlisted the help of an Air Force robot equipped with a giant metal detector, and will set out the second week of September to find the boat he believes is still buried.
The boat, dubbed by some "the holy grail of the exploration," would solve a brainteaser for archaeologists and historians if it is found.
"What we would learn that nobody knows is exactly what that thing looked like - the engineering," Karsmizki said. "What was it that they had imagined and then constructed?"
The journals say Lewis designed the frame, which was fabricated by Harper's Ferry arsenal in West Virginia. The expedition carried the 220-pound frame to the great falls, and assembled it at the explorers' White Bear Island camp.
The frame came in 10 sections, so it could be adjusted depending on the availability of materials for covering it. Fully assembled, the government vessel was 36 feet long, 2 1/2 feet deep and 4 1/2 feet wide. The frame was covered with elk and buffalo hides and sealed with a mixture of beeswax, animal fat and charcoal.
"But it didn't work," Karsmizki said. "It floated briefly."
Lewis believed that with more time, he could have repaired the boat. But pressured to get across the Rocky Mountains before winter, Lewis and his crew buried the boat along with a cache of other items they intended to salvage on their return trip the following year. They wrote of returning to the cache, but never mentioned the boat frame again.
Karsmizki believes it is still there, but not everyone agrees.
"We believe it would've made more sense to take that with them," said Dick Boss of the Lewis and Clark Interpretive Center.
Karsmizki said the only one way to find out is to look. Based on Lewis and Clark's maps and journals and data gathered from a hand-held metal detector, Karsmizki has narrowed the coverage area down to 15 acres.
David Weston of TechLink, a NASA-funded program at Montana State University that matched Karsmizki with the Air Force's technology, said there's probably other metal buried in the field.
"The magnetometer system will find whatever metal is buried up there," he said. "It's also the site of Lewis and Clark's camp, so they should find that as well. There's also an irrigation pipe, buried power lines, any junk left by two generations of farmers."
Karsmizki said the research suggests the boat would be about 60 percent intact, and the robot will detect any rust. Its size and shape would help to differentiate it from other objects.
Any items found in the river bed must be turned over to the military, although it is too early to say which branch. Laws that allow archaeologists to keep what they salvage do not apply because the boat is a government vessel.
Because Lewis and Clark were military men, the Air Force loaned Karsmizki the robot at no charge. It weighs 4 tons, is 10 feet long and 5 feet high, and was built to locate buried bombs and land mines.
The robot moves on tracks and is armed with a Global Positioning System, making it more accurate and faster than any other available method for finding buried metals, Weston said.
"What would have taken Karsmizki two years will take the robot a couple of days," he said.
Paul Carpenter, technology transfer manager at Tyndall Air Force Base in Panama City, Fla., said the project gives the Air Force a chance to prove the versatility of military technology.
There is concern that if the boat is located, it will be expensive to dig up and preserve. After being buried for 200 years, the vessel will deteriorate rapidly when exposed to air.