One 10 ft. length of 1.5" Schedule 40 PVC pipe.
All parts from Orchard Supply Hardware (OSH) except boat fender, which can be purchased from West Marine but I use the ones I find floating in the harbor.
Hacksaw (for cutting PVC pipe)
Cut the 1.5" pipe into the following lengths:
20" (for pipe along bottom of fender)
Glue the parts together as in the photo. Cut off the bottom 12"-18" of the wooden brush handle, wrap with duct tape for a tight fit inside the 1" diameter pipe.
Drill through the 1" PVC pipe and wood brush handle and lock in place with the machine screw and nut and washers. This is important, to prevent rotation of the brush inside the pipe.
Glue the brush head to the brush handle with the waterproof wood glue. Otherwise it will rotate and start to unscrew at the connection.
Note: the photo shows two version, the MK-I and the MK-II. These instructions are for the MK-II. The MK-I is made with all 1" pipe and does not need the reducer bushing. However it was found to be too flexible, and the handle is a little too short, making it less comfortable to use than the MK-II. The MK-II also uses a larger fender to produce more upward force on the brush and better scrubbing action.