Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
It's the major factor. In still water a single person can move a ship
weighing many tons. You'll not do that with a similar weight vehicle.


Due to the tyre rolling resistance.

I can in fact push a van weighing several toinnes on well pumped up
tyres on a dead smooth flat road.

I'm talking about a small ship like say a trawler where I've seen it done.

I'll bet you'll not move a truck weighing anywhere near as much.

As I said, that's because of the tyres.

Whether you call that friction is up to you. Personally I dont.
Friction to me is sliding contact between hard surfaces, or fluid over
a surface.

If you did in fact have a classic frictional case as a boat hull in
water, you very quickly find that cars go faster than boats of the same
weight for the same power

Tyre rolling resistance represents almost a fixed drag component
irrespective of speed.


Boat hull resistance is purely a function of wetted area and speed.

Air resistance is more complex, because air is more compressible. Its a
function of frontal area and shape.





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