The fire broke out about 11:45 a.m. on April 4 aboard a 39-foot Bayliner moored at West Shore Marina, 3900 Harborview Dr.
Several engines and the West Pierce fireboat Endeavor were dispatched, but the boat owner and a bystander had already brought the fire under control, according to Gig Harbor Fire and Medic One. A minor injury was treated at the scene.
The fire was believed electrical in origin. No fuel or oil spill was detected, firefighters said.