Capt. Ed Morehouse loves being at the helm of the nation's biggest, most powerful dredging ship, running its three massive drag arms along the bottom of the Mississippi, sucking up muck at the rate of 7,000 dump-truck loads a day.

But most days, Captain Ed -- the name embroidered on his U.S. Army Corps of Engineers uniform -- commands his stateroom desk.

Under lobbying from the dredging industry, Congress in 1978 ordered the Corps to do less dredging and give outside companies a cut of the business. The argument was that private enterprise could do the job more cheaply and efficiently.

One result: Taxpayers pay about $8.4 million a year just to keep the massive U.S. Dredge Wheeler tied up at the dock in New Orleans.

"It's actually a little frustrating to know that you've got this ship, the most powerful dredge in the U.S., and you can't use it," Morehouse said last month, on board the vessel he has commanded for 14 years.

The Wheeler is 400-foot black-hulled behemoth, bristling with pipes and machinery. On good days, it could keep vital ship channels clear from Brownsville, Tex., to Key West, Fla., and was specially designed to vacuum the tricky entrance to the Mississippi.

Under law, the Wheeler is allowed to work only 55 days a year as part of what the Corps calls its "ready reserve" -- a fleet that supplements privately operated dredges.

"Competition is a good thing," said former senator J. Bennett Johnson, a Louisiana Democrat who helped put the restrictions on the Corps' dredging fleet.

But the Government Accountability Office, Congress's watchdog agency, has suggested, along with others, that this is not a good deal for the taxpayers.

"This is a really stupid way to run the country," said Rep. Peter A. DeFazio (D-Ore.), who has fought the restrictions on the Corps for years. Two of the Corps' remaining four dredges -- down from 14 in 1978 -- are in the Pacific Northwest.

Shipping companies do not like the restrictions, either. "The net result is that it drives up the cost of dredging," said Channing F. Hayden Jr., president of the Steamship Association of Louisiana. "It doesn't make a lot of sense."

The tiny dredging industry vigorously disputes these criticisms, saying its boats work more cheaply.

"We think the Wheeler is working exactly as Congress intended, and that is to serve as an insurance policy," said Jim Rausch, executive director of the Dredging Contractors of America.

But the GAO, in a 2003 report, said the restrictions "have imposed costs on the Corps dredging program, but have thus far not resulted in proven benefits."

The agency offered no dollar figure on how much this is costing the government. But it said the number of dredging companies has shrunk from seven to five since the restrictions took hold, the number of bids per project has gone down, and more and more of the bids have been coming in higher than the Corps' estimates.

As for the Wheeler, the ship's productivity has been slashed by 56 percent, but its costs have gone down only 20 percent. And the crew must find work to do.

Morehouse spends much of his day on administrative tasks -- "You know, meetings, the classic stuff" -- and upgrading the vessel's complex hardware, which includes computers, gauges and video screens with representations of the drag arms.

Morehouse emphasized that he stays busy, but he also said he and officers are trained for more exciting things.

"We have highly trained mates that are walking around the ship making sure it doesn't pull away from the dock, and overseeing contractor work, and doing other things besides what they are really here to do," Morehouse said.

Capt. Ed Morehouse gives a tour of the U.S. Dredge Wheeler at the Army Corps of Engineers wharf in New Orleans.