A very good question for which I haven't been able to find any official answers. Here are some thoughts: - Wear of the cable at the shore ends. Just as abseilin

A very good question for which I haven't been able to find any official answers. Here are some thoughts: - Wear of the cable at the shore ends. Just as abseiling reduces wear on rope compared to lowering, ferry mounted drive means limited dragging across what could be possibly very abrasive surfaces at each shore (sand, rocks, etc). Instead cables get lifted up and lowered down gently. - A cable ferry pulls tension on one side allowing the other side to drop down. If you've ever navigated around a busy cable ferry you'll know that you don't wait for it to stop at either side, you just pass behind it based on current direction. To replicate this functionality you'd need motors for pulling from either side (which you've identified). In that light an electrical cable running to the centre is a quite efficient solution. - The ferry could require power anyway for a range of functions like raising and lowering the drawbridge (I wonder what the proper ferry term for this is).