Sausalito police said a man stabbed another man on a sailboat at the Schoonmaker Point Marina on Sunday evening.
Police responded to the marina at 85 Liberty Ship Way around 7:45 p.m., police Lt. Stacie Gregory said.
The attack against the 37-year-old man by Roman Hunt, 35, of Sausalito, occurred during an argument and both men had been drinking alcohol, Gregory said.
The victim was treated at the scene by responding firefighters for a half-inch cut to his thumb and a cut to his forearm, Gregory said.
Hunt was booked into Marin County Jail on suspicion of assault with a deadly weapon, Gregory said.