Quick and easy, won't add much weight, probably less than a pound....

- wash off any oil and dirt with detergent, rinse well.

- dry thoroughly.

- sand all the gloss off to a uniform dull surface everywhere to give the paint some "tooth" to bond onto.... surface prep is critical, an orbital sander helps with time.

- dust off, allow to dry again if washing or wiping with damp cloth to dust off

- spray with several cans of Tremclad or Rustoleum... or brush/roller with an enamel like floor and porch paint (although, probably heavier wrt weight).

-  get on the water and start scratching up the canoe again... good luck.