This news feed just came in for a new boat propulsion system: Japanese sailor first to cross the Pacific in a wave-powered boat. This is a boat propelled by wave action that was just sailed across the Pacific Ocean solely by wave power. The journey took 110 days, but hey, he made it, okay?
He says his target was to arrive in late May so arriving in July he was just a bit overdue because of low wave action. That is an interesting but unique version the doldrums.
Obviously it's not quite up for pulling water skiers, but look at the Wright Brothers first flights: the initial experimental airplanes weren't exactly barnstormers. The adventurer, Kenichi Horie, does admit it's only a start in an alternate energy system where no one else has been looking. It is remarkable nonetheless.
Maybe he could try this: using solar power to heat water to steam an jet this into water ahead of the wave powered fins to speed up the action. There's some other alternates I'd try first, like an electric motor.
