In message
"Ewan Scott" wrote:

Snip fair discussion.

Rather than nonsense, just a different view.

I know, but you can't have a debate when everyone agrees can you? I
still don't see how you manage to go slower than the flow of the water
when going downstream unless you are doing so deliberately or you are
being blown backwards by the wind.

Honestly, sitting in the Inazone waiting for others to catch up/ play on
waves - and not in any eddy, I was slowly drifting downstream, but small
twigs etc were floating slowly past at a faster rate. If we turn sideways to
the current we drift even slower - gives more time to read approaching
rapids.

I'd find that a bit hard to believe. What will make a difference is
wind/breeze. The twigs may have been going faster than the water because of
wind, or more likely a head wind was slowing you down. In the absence of
wind effects, a boat should travel at the same speed as the water.

I think the original discussion was over a comment that progress was slower
downstream. I took that to mean that speed over the water was less when
going with the current than against it. Thus 2kph current and 4kph boat
speed = 2kph upstream, but not quite 6 kph downstream. This I find quite
likely, as there's less incentive to push hard when going downstream. Also,
in shallow water, bottom drag will be greater going downstream, as that is
related to speed over the ground.

Alan Adams

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Alan Adams

http://www.nckc.org.uk/