Re: [Paddlewise] speed with versus against the current

Kirk wrote;

>This past weekend I did a sea kayak race in the Essex
>river basin (massachusetts coast, one of my favorite spots
>for a day trip).  On the trip out to the turn around island
>I stayed dead even with someone, going with the current.  When
>we turned around and headed back up I immediately pulled ahead.
>
>This is something I've experienced before.  I had assumed the speed of a
>canoe/kayak was constant relative to the current.
>
>Could someone explain what would make one hull faster, than the other
>with the current versus against it.

I would suspect that both of you were actually working harder against the
current in whihc case your speed through the water was greater and the boat
with the higher prismatic coefficient had lower wave making resistance at
the higher speed.


>This time the wind direction and waves could have been a factor, last time
it
>was in windless calm conditions.

This could also have been a factor.

>
>I'm assuming both of us continued putting in the same level
>of effort before and after the turn around.

Always a dangerous assumption :-) The psychology of the race has a huge
impact. Some people feel defeated when paddling against the current and
others feel challenged.
>
>The first time I experienced this was against a marathon flatwater canoe.
>I attributed the difference to their boat slicing through the water as
>the water was displaced and ours riding up onto the water as it displaced
>the water.  This time it was a Seda Glider versus a VCP Nordkapp.

This is not likley a factor since canoes and kayaks don't plane in the
hydrodynamic meaning of the word. Marathon canoes almost always have high
prismatic coefficients and are at their best at high speed length ratios.
The Glider should be faster than the Nordkapp in racing conditions and at
racing effort. Of course, to talke advantage of the length etc. one has to
be paddling at Speed/Length >1.0 . Below that they are less efficient
because of the added wetted surface.

Cheers,
John Winters
Redwing Designs
Specialists in Human Powered Watercraft
http://home.ican.net/~735769/


***************************************************************************
PaddleWise Paddling Mailing List
Submissions:     paddlewise_at_lists.intelenet.net
Subscriptions:   paddlewise-request_at_lists.intelenet.net
Website:         http://www.gasp-seakayak.net/paddlewise/
***************************************************************************