Comment Re:What Bat Villian designed this boat?!?! (Score 1) 164
Sailing ships can be becalmed for days or even weeks. This is more of a problem the bigger the ship, as the more wind you need to start it moving again. Even at the best of times, their speed is highly variable, depending on wind speed and direction - if it's a head wind then they need to tack, which can significantly reduce their maximum straight-line speed, if it's a run or a reach then they can go faster. This makes them tricky from an economic perspective, where you need to book dock time well in advance to get goods loaded and unloaded and where your customers typically require things delivered within a fairly narrow window. For low-priority goods, it might be fine, as long as you were willing to wait at the far end for a few days for a free slot in the unloading dock.
There have been some attempts to address this, by flying kits up in the jetstream and using their rotation to drive a screw. This has a lot of potential, but the last demo I saw was only generating 20% of the energy required to propel the craft - the rest came from burning oil.