User:Vincecate/SkyWay
If two seasteads are using kite and sea anchor for mobility, they could come close enough that someone could use a crossbow to shoot across thin line, which could be used to pull across a thicker line, and that to pull across a cable. After the cable is secured the sea anchors could be deployed and the kites for the two seasteads could pull to the sides so that the cable between the seasteads was pulled tight. Then a cart could move back and forth between the seasteads on the cable carrying cargo and/or people.