RedactedNarrative: The vessel was missing a hatch to keep the water from entering the transom area and bilge. The vessels bilge pump was not functioning, and the vessel sank.  On July 3, 2021, at approximately 1800 hours vessel FL9542JH was traveling North through Largo Sound. The vessel was operated by OP1 was traveling back from Nest Key. From the statements provided OP1 noticed the vessel having trouble getting on plane. The vessel began to sink lower in the water and the bilge pump was not working. The vessel took on water and came to rest on the bay bottom in approximately 4 feet of water. Once the vessel was recovered by commercial salvage company, I noticed a transom deck hatch was missing (pie eye). The hatch was open and just above the water line on the transom of the vessel. The open hatch allowed water to enter the transom and bilge area of the vessel.  The missing hatch along with a non-functioning dewatering device contributed to the vessel sinking.