After weeks of speculation about a four-story structure built on a barge in New London harbor, Coast Guard documents obtained Thursday show that Google is indeed involved.

When Turner Construction first leased space from Logistec USA at the Admiral Harold E. Shear State Pier in New London in May to build the structure on the barge, Coast Guard officials met with project managers from Google, Turner and Cianbro Corp. to discuss the project and expectations, according to documents obtained by The Day Thursday through a Freedom of Information Act request.

Construction on a structure made of container units continued through July. Coast Guard Sector Long Island Sound took part in a conference call on July 1 with a naval architect, a marine transportation company and Michael Tierney, of Google Glass, to review the plans.

The purpose of the vessel is not described in the documents, but they reveal a plan to operate the vessel in various ports, the first being New York Harbor.

News reports over the past several weeks have included speculation that the structure, since towed to Maine, and a matching barge in San Francisco Bay, could be floating data centers owned by Google or could be retail stores for Google Glass, the Internet-connected eyewear.

This week, however, work on both barges reportedly has stopped. Google has not commented on the matter.

The Day reported Sept. 28 that no one involved with the construction in New London would say or even knew the mysterious structure's purpose. The building attracted attention all summer.

The modular containers were built in San Francisco and shipped to New London to be installed, and Coast Guard inspectors on both coasts coordinated with each other during the construction in New London, the documents show. Coast Guard Sector San Francisco was responsible for overseeing the units. Sector Long Island Sound and Sector San Francisco discussed issues that arose during the work.

The barge in San Francisco Bay is "BAL0010." The barge that was in New London is BAL0011, the sister to BAL0010, according to the Coast Guard. Both are owned by By and Large LLC, in Wilmington, Del.

Sector Long Island Sound inspected the systems on board the 249-foot passenger barge in New London, which was built in 2011, and found them all to be satisfactory.

The modular units were installed in New London beginning in June, but on July 18 the Coast Guard was informed that the project had been suspended and the vessel would be boarded up. The Coast Guard was asked about moving the barge to New York or some other port.

A tugboat from Portland Tugboat LLC led the barge down the Thames River Oct. 9, en route to Maine. In Portland, Cianbro plans to install undisclosed technological equipment inside the building.

Coast Guard officials have said they could not discuss the matter in detail because of issues of commercial confidentiality.

The Coast Guard's 11th District in California released a public statement Thursday, saying that during the course of vessel inspections, Coast Guard personnel often are privy to sensitive proprietary information.

"Regardless of the company or entity involved, the Coast Guard has an obligation to protect sensitive proprietary information, as a company's competitive posture and business interests depend on it," the statement said. "Regarding the barge BAL0010 moored at Treasure Island in San Francisco Bay, Coast Guard personnel have been onboard to conduct routine inspections and ensure compliance with applicable, safety, security, and environmental protection regulations."

The statement does not mention Google.

j.mcdermott@theday.com