V1 was heading north on East Lake Vermillion in McCook County South Dakota. V1 was in the northernmost portion of the lake where it can be shallow. O1 noticed water in the rear of V1. O1 turned on V1 bilge pump. O1 noticed more water in V1. O1 slowed down. O1 and P1 climbed into the front of V1 to offset the weight of the water. O1 handed P1 a PFD. As V1 went completely underwater P1 handed O1 the PFD because O1 could not swim and P1 could. The other PFD went down with V1. O1 and P1 waved down another vessel. The additional vessel towed in the submerged V1 along with O1 and P1. 
WCO observed V1 submerged at the east boat ramp of East Lake Vermillion. O1 was able to get V1 onto the trailer. WCO inspected the damage to V1. There was a hole approximately 12" in diameter punched into the starboard side of the hull about 2/3rds of the way back from the bow. WCO determined from interviewing O1 and P1 and based on the location of the accident that V1 struck a submerged rock. WCO investigated for the presence of alcohol. O1 showed few indications of alcohol consumption. WCO could detect the odor of an alcoholic beverage on O1. WCO ran O1 through field sobriety test as well as a PBT. O1 's PBT result was a .007BAC.
CANISTOTA