An entry-level canoeist may find the canoe slightly "tender" -- the polite nautical term for vulnerability to capsizing. Although that tender feeling goes away with experience and more time in the boat, you may want an artificial way to stabilise the canoe. A removable, inflatable sponson stabilises a canoe when needed. If the canoe capsizes, a sponson stabilises it for the paddle back to the bank.
Cut four pieces of PVC fabric into 120 by 30 cm (4 by 1 feet) rectangles. You can vary the length to match the distance between your canoe's front and aft thwart.
Cut four pieces of PVC fabric into rectangles 22.5 by 15 cm (9 by 6 inches) wide.
Cut two 30 cm (12 inch) pieces of vinyl tubing.
Brush a 2.5 cm (1 inch) strip of HH-66 vinyl contact cement on one side of each of the four larger pieces of PVC fabric. The strip follows the outline of the fabric; when glued together, it becomes the seam of an inflatable bag.
Coat one end of the vinyl tubing with HH-66 vinyl cement. Glue it to one piece of PVC fabric so the longer end faces outwards and acts as an inflation tube. Repeat for the second piece of vinyl tubing.
Glue the larger pieces of PVC fabric together to create two inflatable bags. Work carefully to ensure that the seams don't leak. Clamp each side of the vinyl tubing to guarantee that the seams are airtight.
Glue your smaller pieces of fabric to each end of the inflatable bag to form a sleeve for nylon webbing to run through. Repeat for each bag.
Run webbing through the sleeve of one bag, under the canoe, through the sleeve of the second bag, around the thwart, back under the canoe, and around the other side of the thwart. Clip the ends together using a side-release buckle. Repeat for the other thwart.
Inflate the bag and plug the end of the vinyl tubing.
A canoe stabiliser cannot replace knowledge. Learn proper rescue techniques from a qualified canoe instructor.
Work with HH-66 in a well-ventilated area.