After touring the burned USS Miami, Congressman Joe Courtney said it doesn't appear as though the hull was compromised in the fire.

The submarine's hull is dotted with marks, inches apart, where testers pressed a device that measures sound waves to check the integrity, Courtney said Tuesday. The intense heat from the May 23 fire could have changed the circularity and metallurgical makeup, which could have affected plans to repair the submarine or made the endeavor much more costly.

The Navy has said it expects the repairs will be done by April 2015 and will cost about $450 million.

"That's why the repair estimate looks solid. They are not going to have to do anything major to the steel in the hull," Courtney, D-2nd District, said in a telephone interview after the tour. "They'll re-insulate it, re-cable it and re-hang the fixtures that melted."

The Miami (SSN 755) was in a dry dock at the Portsmouth Naval Shipyard in Kittery, Maine, for maintenance and upgrades when it caught fire May 23 and burned until the next day. The shipyard worker accused of setting the fire has been charged with arson.

The Navy awarded a $94 million planning contract to Electric Boat, teamed with Huntington Ingalls Industries, to support the engineering that will guide the repairs and to purchase parts, such as piping and electrical cabling, for the Groton-based submarine. It includes an option worth an additional $6 million.

"There's no wavering as far as the plan to go ahead and do this," Courtney said.

Tuesday was the first time since the fire that Courtney had toured the submarine. He met with Capt. Bryant Fuller, commander of the shipyard.

"They've made great progress in terms of cleaning the place up and it's down to just the real skeleton on the inside," he said, adding later, "The folks from EB will start coming up in the spring to start the reconstruction."

Courtney said the repair contract also is expected to go to EB, but the Maine shipyard and Huntington Ingalls also would be involved. Because the Miami is staying in Maine, the USS Providence, which was scheduled to be repaired at the shipyard, will now go to EB. Courtney said it would take too much time and money to tow the Miami to Connecticut.

j.mcdermott@theday.com