On my bolsters, there are screws that were put through the grommet holes on the bottom edge of the bolster. If you can get your hand behind the gunwale, feel for the screws and then look for the grommet. Use a screwdriver inserted through the grommet into the screw head. It's a bit tricky
Once the screws are removed and there wont be a lot of them, the bolster lifts up. It is hung on brackets..
Getting the screws back into the same holes later can be a challenge. It's easier to just make new holes.
