I have recently purchased a Clearwater 17' skiff, and I cannot pic between a Riptide 55# or 70# thrust. I really don't want the weight of 2 batteries, or charging them, but then again, sometimes it is awfully gusty and the current can pick up around AB. So can a 55# pull around a 17' skiff for the afternoon? Or should I go with the 70#? Thanks, CF.