The "Land Tortoise" was built in 1758, as part of a British effort to regain control of Lake George after the loss of Fort William Henry at the south end of the lake in 1757. She was built by provincial militia forces under the direction of Captain Samuel Cobb of Falmouth, now Portland, Maine. She was built in just over a month, launched, tested ("rowed well with 26 oars") and then two days later intentionally sunk by adding ballast with plans to re-float her in the spring of 1759. The location where she was sunk was too deep for recovery, and a new radeau, the "Invincible", was built in 1759.