On 30-May-2004, (William R. Watt) wrote:

Where on earth do you get that breakdown? Friction resistance
80 times wave resistance?

"Winter's" data at hull speed and total resitance equal to 1/20 hp.
ie the data graphed on Winter's web site.

From your other message:

knots: 2 2.6 3 3.5 4 4.6 5 5.5 6
lb friction: 2 2.5 2.75 4 4.75 5 7 8 9
lb wave: 0 0 0 .05 0.75 3 7 15 20
lb total: 2 2.5 2.75 4.5 5.5 8 14 23 29
================================================== =========
hp: .01 .02 .03 .05 .07 .10 .20 .40 .53

Take a look at the data when you get into the 0.1-0.25hp range.
The lower hp is for the fit paddler and the upper is for the serious
competitor. In this range, the skin friction and wave resistance is
of the same order of magnitude [ (3,5), (7,7) ]. The hull is designed
for use in that speed/power range - upwards of 4.6 kt ( 8.5 kph) That's
a bit faster than I can paddle my kayak for an hour.

If a person is routinely paddling at 3-3.5 kt, they could use a shorter
kayak and not get as much skin friction and still not be pushing waves
around much. It would be easier to paddle and more maneouverable to boot.

The problem with your analysis is that 1/20 hp is low for a fit person.
Also, this data is suspect - most kayaks in the Sea Kayaker reviews are
not in this range. For a recent review of the Solstice GT:

Speed 2.0 3.0 4.0 4.5 5.0 6.0 (kt)
Solstice GT 0.96 2.01 3.66 5.31 8.06 14.23 (lb)

As you can see, the data you provide is quite a bit higher than what the
Solstice shows. Here's some mo

http://www.greatlakeskayaker.ca/speedVsResistanceGraphs.htm
(I make no promises whether this web page will show in anything other
than Internet Explorer - sorry, it's an exported Excel spreadsheet page).

Elite paddlers can put out about 0.3 hp. A fit recreational paddler
can put out about 0.08 to 0.1 hp.

according to teh data on Winters' webiste you you have just
destroyed your earlier argument. at less than 1/20 hp the "boat" (canmoe
or kayak or whatever Winters' data represents) is harldy moving at all.

??? 3.5 kt isn't "hardly moving". I'm not sure what earlier argument I
destroyed. You'll have to be more specific.

Mike

"Michael Daly" ) writes:

Also, this data is suspect - most kayaks in the Sea Kayaker reviews are
not in this range. For a recent review of the Solstice GT:

Speed 2.0 3.0 4.0 4.5 5.0 6.0 (kt)
Solstice GT 0.96 2.01 3.66 5.31 8.06 14.23 (lb)

As you can see, the data you provide is quite a bit higher than what the
Solstice shows. Here's some mo

http://www.greatlakeskayaker.ca/speedVsResistanceGraphs.htm
(I make no promises whether this web page will show in anything other
than Internet Explorer - sorry, it's an exported Excel spreadsheet page).

thanks. I'll take a look.
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