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Primbee clip from last week

Created by Windsurfunstu Windsurfunstu  > 9 months ago, 10 Jul 2015
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Windsurfunstu
Windsurfunstu

NSW

177 posts

10 Jul 2015 8:55am
Thought Id share my latest attempt at editing. A clip from Primbee last week.
tazmania
tazmania

WA

83 posts

10 Jul 2015 7:02am
Very nice. I can see why you've got the helmet on. If you stack it's only what, knee deep all the way?
N1GEL
N1GEL

NSW

861 posts

10 Jul 2015 9:25am
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tazmania said..
it's only what, knee deep?


About 1/2 that at low tide. It's extremely shallow. You can see the depth at end of the video.
Dezza
Dezza

NSW

955 posts

10 Jul 2015 11:48am
love it

that JP 101 looks nice
Ian K
Ian K

WA

4164 posts

10 Jul 2015 9:58am
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N1GEL said..



tazmania said..
it's only what, knee deep?





About 1/2 that at low tide. It's extremely shallow. You can see the depth at end of the video.




You get some idea when sailing by looking at the chop. At 1.05 on the video you can sort of see a longer wavelength and a bit more height to the chop. That's about knee deep. At 2.26 the waves have bunched up and gotten smaller. That's 1/2 knee deep. It's a bit of guess work, weed also has an effect. Also if you note that the board is starting to feel really slippery, and your speed is rising due to unknown causes, it's probably the ground effect kicking in.

I've just googled "planing hulls in shallow water" The best I've come up with is this graph
http://hydrocompinc.com/blog/time-trial-racing-–-deep-water-versus-shallow-water


At low non-planing speed the shallow water curves are above the deep water curve, but once the model starts planing the shallow water has less drag. You probably should compare the curves by looking along horizontal lines. Your speed increases until the forward lift of the sail equals the drag of the hull. So all sails being equal, for 20 units of sail lift the speed in flat shallow water vs flat deep water would be up from 2.5 to 3.4 units. ( But it's not that simple because as you go faster you'll lose apparent wind and sail lift decreases, so somewhere in between.)

WaynoB
WaynoB

NSW

393 posts

10 Jul 2015 3:00pm
Nice video Stu, looks like you were having a hoot.

Sweet spot indeed. On my bucket list.
dweller
dweller

NSW

134 posts

10 Jul 2015 4:14pm
Great video Stu. When did you shave?
Windsurfunstu
Windsurfunstu

NSW

177 posts

10 Jul 2015 7:52pm
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dweller said..
Great video Stu. When did you shave?



Need to find .21 of a knot so the beard had to go! Oh and the Mrs told me to
dweller
dweller

NSW

134 posts

10 Jul 2015 8:46pm
You out over the weekend? Sunday and Monday look like fun
shear tip
shear tip

NSW

1125 posts

10 Jul 2015 9:14pm
Great vid Stu - same again on Sunday
Windsurfunstu
Windsurfunstu

NSW

177 posts

10 Jul 2015 9:24pm
Thanks guys. Yeah I'm working Sunday but after a lucky break I'm now in the clear for Monday Still considering a sickie Sunday though
Windsurfunstu
Windsurfunstu

NSW

177 posts

12 Jul 2015 7:58am
If the first links not working maybe this one will
shockwave
shockwave

NSW

8 posts

16 Jul 2015 11:15pm
Good sailing love the G'n'F'n'R's!
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