I taught canoeing for several years. For a single paddler, the secret to avoiding shoulder pain or fatigue is changing sides periodically (whenever one arm begins to tire a bit)and utilize something called the "J stroke" for going in a straight line. It involves dipping the paddle at the bow, pulling it alongside the canoe, turning the blade 1/4 turn (so that it becomes a rudder) and pushing out and away from the boat just before it exits the water for the next stroke. With a little practice, it is easy to do and far less tiring. The other secret (for stability) is to keep your weight low by kneeling on a pad, rather than sitting high on a seat. These are old native american tricks picked up by French Voyageurs and used very effectively. Of course, if two are paddling, one paddles on each side, changing sides simultaneously, as necessary, on a voice command from the stern paddler. If you follow these procedures, you should have no problem keeping your instruments dry.