Washington, U.S. — Great American Insurance Company has asked a federal court in Western Washington to declare it has no obligation to defend or indemnify Alpha Marine Installations LLC, a marine construction company, in a lawsuit involving the alleged destruction of an undersea electric cable worth up to $20 million.

The case stems from a November 2022 incident near Anderson Island, Puget Sound, when Alpha Marine was hired to anchor a boat mooring buoy in Thompson Cove. Tanner Electric Cooperative, the local utility provider, claims that during installation, Alpha Marine's use of underwater drilling equipment damaged a 25,000-volt submarine transmission cable that served as a backup to the island’s primary power line. Some residents reportedly experienced temporary power outages as a result.

Tanner Electric filed suit in state court alleging negligence, claiming Alpha Marine failed to identify existing infrastructure, comply with statutory excavation requirements, and heed clearly posted warning signs that read, “DANGER CABLE CROSSING DO NOT ANCHOR.” The utility estimates replacement costs for the damaged cable at $20 million to $25 million, saying repairs are impossible.

Great American Insurance argues that Alpha Marine’s policy does not cover the claims due to exclusions for underground property damage and damage arising from operational errors. “The property damage alleged by Tanner Electric arises directly out of Alpha Marine’s buoy installation operations,” the insurer said in its filing, adding that the exclusion applies even though Alpha Marine was not performing work directly on the real property itself.

While Great American is covering Alpha Marine’s defense under a reservation of rights, the insurer maintains the underlying claims are outside policy coverage. Legal representatives for Alpha Marine have not provided comment, and attempts to reach Great American’s representatives were also unsuccessful.

The dispute has been filed in the U.S. District Court for the Western District of Washington under case number 3:26-cv-5083, with Judge David G. Estudillo presiding. The case highlights ongoing tensions in marine construction insurance and the challenges of addressing accidental damage to critical infrastructure.