RedactedNarrative: V1 was heading down river when the accident occurred.  Operator stated there was water inside V1 due to previous rainfall the night before; therefore he pulled the plug and placed it on the seat, intending to run V1 and drain the water out. He then stated at one point the plug fell down by the transom and he began to struggle to find the plug and manage control of V1 at the same time. He then impacted the bank where he was partially ejected and V1 quickly began to take on water via the plug hole.  V1 quickly capsized due to the strong current and completely submerged. Operator was able to self-rescue and climb out on the bank.