The important bit: > They also don't require much of any minding. A simple red/green traffic system on the bridge tells the crew when to activate or inactivate

The important bit: > They also don't require much of any minding. A simple red/green traffic system on the bridge tells the crew when to activate or inactivate the WindWings. Once online, they respond automatically to changes in the wind and trim themselves for optimum speed. This allows the diesels to be throttled back without the ship slowing down. No profit-motivated shipping company wants to hear about "needs additional crew...training...", and that stuff would also be an added barrier to fast adoption. On the downside - installation can't be cheap, and the system looks fairly incompatible with modern container ship designs.