4 ms·

I don’t understand why they would think this to have low drag. - Displaced volume wouldn’t be lower than that of a traditional ship (likely even quite a bit hi

I don’t understand why they would think this to have low drag. - Displaced volume wouldn’t be lower than that of a traditional ship (likely even quite a bit higher because the wheels would add mass and the hull would have to be stronger than one that rests on the water) - Surface area would be higher than that of a single hull. Also, looking at this as a variant on the paddle steamer (https://en.wikipedia.org/wiki/Paddle_steamer#Seagoing_paddle_steamers https://en.wikipedia.org/wiki/Paddle_steamer#Seagoing_paddle...), didn’t we already know in 1897 that screw propellers are a lot more efficient? SS Archimedes (https://en.wikipedia.org/wiki/SS_Archimedes https://en.wikipedia.org/wiki/SS_Archimedes) was built in 1839. So, what was the thinking? It being easier to have low rpm in steam driven engines, and that compensating for those disadvantages?

eternauta3k 3y ago
Part of the drag scales with the relative velocity between the surface of the wheel and the water. If they move with ~0 relative speed, drag is reduced.
bluGill 3y ago
Paddels can he just as efficent as screws but only with mechanical comylexity which makes them unreliable.
s1artibartfast 3y ago
Wheels add mass and cross sectional drag to my car, but rolling more than makes us for it. I assume the thought was similar. Some of the energy is lost to friction, some is lost to the motion of water. Imagine a ship where the hull sufface has the same relative velocity as the water. It would behave the same as a frictionless ship.
usrusr 3y ago
Isn't it rather obvious that they thought friction was the main (or the sole!) component of drag? If displacement waves didn't exist, or did not cause meaningful drag, floaty wheels might even have taken over already in the age of sail.
lttlrck 3y ago
Ignoring why they didn't intuit that it would not work, I don't understand why the models didn't demonstrate it.

eternauta3k 3y ago

Part of the drag scales with the relative velocity between the surface of the wheel and the water. If they move with ~0 relative speed, drag is reduced.

bluGill 3y ago

Paddels can he just as efficent as screws but only with mechanical comylexity which makes them unreliable.

s1artibartfast 3y ago

Wheels add mass and cross sectional drag to my car, but rolling more than makes us for it. I assume the thought was similar. Some of the energy is lost to friction, some is lost to the motion of water. Imagine a ship where the hull sufface has the same relative velocity as the water. It would behave the same as a frictionless ship.

usrusr 3y ago

Isn't it rather obvious that they thought friction was the main (or the sole!) component of drag? If displacement waves didn't exist, or did not cause meaningful drag, floaty wheels might even have taken over already in the age of sail.

lttlrck 3y ago

Ignoring why they didn't intuit that it would not work, I don't understand why the models didn't demonstrate it.