You're prepared for the worst by bringing along a third oar, but you'll need easy access to it when you have to move fast. The perfect solution is an NRS Spare Oar Keeper with its quick-release side buckle and large O-ring. Fits Carlisle and Cataract Oars.
Comments about NRS Oar Keeper - Big Dog Buckle - Closeout:
I wanted to use them to carry my oars just in case my trolling motor went down. Kinda like the spare tire in my car. They are much heavier than I expected so as to not be useful, you could strap down a 747 with them. I pitched them and made what I wanted out of a couple dog leashes.