RedactedNarrative: Operator and two passengers were heading south out of Mumford Cove towards Fishers Island Sound in a 16' open motorboat after duck hunting. The sea conditions worsened as they entered Fishers Island Sound. The waves became large and the speed/time between each was fast. The vessel took waves over the bow and it began to fill with water. The vessel filled with water and forced the bow under the surface of the water and stern up in the air. All occupants went into the water. The operator lost sight of the passengers and swam to shore and called for help. The passengers were recovered unconscious and unresponsive. They were transported to the hospital and pronounced dead. No PFDs worn. Two dead and one injured.