Roger Murtaugh's Boat was a houseboat that belonged to LAPD Detective Roger Murtaugh. He purchased it sometime into his alcoholic depression and kept it for a few years until it was destroyed by a flaming oil drum.
After killing Darryl Smithers, Roger Murtaugh entered a depression phase and also began drinking alcohol. During his 3-4 days as an alcoholic, he purchased a houseboat and soon began to distance himself from his family as well.
One night, while sleeping in his trailer, he received a visit from Martin Riggs, at Rianne Murtaugh's request, who wanted to see how his fallen partner was feeling. He also wanted to help him regain his self consciousness and focus on the future. Initially reluctant in listening to Riggs, Murtaugh agrees to return to the force, of course when they fall off the boat and soak themselves.
Years later, and nine months after the armored criminal shooting incident, Roger, Riggs, and Leo Getz go fishing on Murtaugh's boat where Leo is attempting to shoot a shark that he caught. Until a Chinese cargo ship arrives; Riggs shoot most of the henchmen on-board, but one of the flaming oil drums shoots from the cargo ship and impales through Murtaugh's boat as Murtaugh and Leo Getz jump clear. The boat sinks underwater, leaving just the buoyancy ring.