If you get caught you should make your way out of the vessel with as little delay as possible. Don't even bother trying to rescue it. Keep your arms and legs as near to your torso as possible to avoid being tangled in any debris beneath the surface of the water. Break free from the backwash and float downstream on the river's current. Exit as quickly as you can once you reach land. After you've gathered your mental and physical strength, it's time to recover your vessel.