On Sun, 09 Sep 2012 17:06:08 +0100, charles
wrote:

In article , The Natural Philosopher
wrote:
charles wrote:
In article , 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.

You only need to look at how much load a single horse could pull on a
canal barge.


Indeed, but it does NOT support his thesis that its 'friction'

but if it wasn't for friction, the wheels would simply spin on the
ground.


T'aint necessarily so. The non-flatness at a macro scale would be
sufficient without any 'real' friction being needed.

--
Rod