Air/Watership Hybrid

[venomousbird]

Imagine a boat that used an electronically controlled airship that was tethered much like a kite sail. This could provide the lift to greatly reduce the drag caused by the water, perhaps could be used in combination with a hydrofoil to allow for a much lower planing speed.

[mydauphin]

I was thinking of an inflatable kite filled with helium to act as sail. Sail design similar to parasail. I like lift idea of helium so it doesn't fall into sea so easily.
Problem is where to attach sail, may be bow of boat. And would it would it be worth it? How much thrust would it pull? The ancient Egyptians used some big kites to move rocks around in the desert.

[venomousbird]

I'm guessing they used balloons as well, considering that they had batteries that will produce hydrogen as a byproduct, they could easily have bottled up the hydrogen and used it to fill lighter than air balloons. . .

I had a concept of how they could have built things with those balloons
Use a balloon that can lift say 1000 pounds, and attach it to a cart with a thousand pound watertank on it

just fill up the watertank to have a neutrally buoyant cart that can be moved almost effortlessly, then when you get it to your quarry, load on your thousand pound rock, and dump the water for an effortless move back to the building site. . . then refill the watertank and dump the boulder, it's effortless construction

[mydauphin]

They where smart than we give then credit for. They build the first cruise ships over 400 feet long, hot tubs, saunas, barbeque's and all the girls your heart could desire. Read about Cleopatra's great barges, They were acutally ocean going ships.