Background

The Tuapeka Turbine operates on a similar principle to the Tuapeka Punt.  The Tuapeka punt travels across the Clutha river at Tuapeka in New Zealand, ferrying vehicles to roads on either side of the river.  It consists of two pontoons which are suspended from a cable stretched across the river, using a pulley and cable connected to the punt.  Once the punt is loaded with vehicles, the operator simply pulls on the tiller linked to two rudders on each pontoon of the punt, to turn the rudders, which turns the bow of the pontoons to an angle to the river flow.  This causes the punt to move sideways across the river, suspended from the travelling pulley.

  The Tuapeka turbine, similarly has vanes suspended from cables/chains on a loop, which are turned to an angle to the river flow, and thus move sideways across the river, pulling the cable/chain which moves in a loop and rotates wheels at each  end of the loop.