RedactedNarrative: Operator advised they were heading back to the boat ramp when V1 lost power.  He had just gotten V1 out of the shop, where they were supposed to replace the fuel filter.  After V1 became dead in the water, the current pushed them into some old wooden pylons  that go across the river.  When V1 reached the pylons, it turned sideways and started taking on water over the starboard side.  Both occupants decided to jump from V1 and swim to shore.  They were wearing life jackets and made it to shore where they spent the night and waited for daylight.  The next morning they were able to walk out and call for help.  The operator made arrangements for retrieval of V1.