The agency sent a letter to the companies -- from whom it seeks multimillion-dollar refunds -- outlining dozens of components on these ships that were problematic.

Lockheed previously said it would not be financially affected by the government's refund request because the faulty ships had structural, not equipment, problems -- meaning only Northrop was to blame.

But the Coast Guard's June 5 letter, a copy of which was viewed by The Associated Press, questions that assessment.

Lockheed is willing to resolve the issues "for which we are responsible," company spokesman Troy Scully said Monday. "We are willing to negotiate with the Coast Guard."

Coast Guard spokesman George Kardulias declined to provide details about the agency's communication with the company.

The Coast Guard on May 17 revoked its acceptance of eight 123-foot patrol boats due to hull buckling. Then, in the June 5 letter sent to Integrated Coast Guard Systems, a joint venture between Lockheed Martin Corp. and Northrop Grumman Corp., the agency said its revocation was partly based on equipment and systems that failed to meet contract requirements, including "class wide issues ... which remain unresolved."

The agency's letter also said it was forced to fix an electronic engine problem and make a software upgrade at its own expense after the contractors failed to do so.

"That's a warning sign," said Jim Krouse, vice president of sales strategy at Government Sales Force LLC, which consults businesses in the federal technology market. "It's distinctly possible" the same equipment issues could arise on other ships being built as part of the Coast Guard's Deepwater modernization program, he added.

The eight faulty ships were removed from the waters off Florida late last year and permanently decommissioned in April. Some of the electronics problems were first identified in 2003, a year after the joint venture was awarded the contract.

Among the problems identified in the Coast Guard's letter were: a radio direction finder used for navigation that did not meet accuracy requirements, emergency power system deficiencies, and data lines that failed to transmit video back to shore.

Scully said the equipment referred to in the Coast Guard's letter all worked before the eight ships were decommissioned. The Coast Guard appeared to agree earlier this year.

In April testimony before a House transportation committee, Rear Adm. Gary Blore said the decision to suspend operation of the boats "was in no way related to ... topside equipment issues."

"The decision was based entirely on ongoing structural problems," Blore said.

Northrop spokesman Bill Glenn on Monday reiterated the company's stance from last month that it is working to determine the cause of the hull problems before "accountability and corrective action" can be taken. Northrop will share its findings with the Coast Guard when its analysis is complete.

In a June 27 letter, the Lockheed-Northrop joint venture said the Coast Guard's request for a refund was not "supported as a matter of fact or law."

The Coast Guard has said it lost up to $60 million on the eight cutters, but hasn't specified the amount of damages it will seek.

The first two National Security Cutters, which are the cornerstone of the Deepwater program and expected to cost about $750 million each, are on schedule. The first one is expected to begin sea trials in October, Kardulias said, adding that its final cost would be available by this weekend. Construction of the remaining six will start after the two sides agree on any necessary changes.

The Coast Guard in June extended its contract with the joint venture for 43 months despite internal and congressional scrutiny of the 25-year program. The deal does not guarantee the award of any future task orders and its value will be determined by further negotiations as work proposals are submitted.

The Justice Department is investigating the Deepwater contract. The agency told Lockheed, Northrop and other contractors not to destroy certain documents, and the companies have said they are cooperating with the investigation.