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-   -   Planing when there are no whitecaps? (http://www.star-board-windsurfing.com/forum/showthread.php?t=7775)

Unregistered 8th December 2009 09:14 AM

Planing when there are no whitecaps?
 
How come I see guys in the magazines planing when there are no whitecaps, and they aren't even on big boards or big sails?

Is it:
a) They are anorexic and weigh about 20kg?
b) New sails and boards are better than my 5-8 year old sails? (surely not!)
c) the photographer has cunningly kept the breakwater out of shot and it is actually 20 knots?

I saw one photo and it said the wind was 4 knots and he was using a sail like 5.6m or something and he was shredding massive waves. How would you even sail out there let alone get cranking fast enough to catch a wave... am I missing something or is it just because Im Australian?

Per 8th December 2009 08:47 PM

Nothing on this planet planes with a 5.6 in 4 knots... Maybe an Apollo with 12 m2 and a 50 kg rider pumping seriousely...
I think the photographers know a few tricks combined with very good sailors (and at least 10 knots).

;-)
Per

Ken 8th December 2009 10:14 PM

In Windsurf Magazine I have noted that in some of the photos of wave sailors, they detail the wind speed plus sail and board sizes. For example, wind - 10-12 knots and a X brand 5.6 sail on x brand board at 80 liters. I fail to see how these guys can get outside the surf line in such light winds, small sail/board and surf.

I have done a little surf sailing along the Texas gulf coast and know that it is impossible to do the above even if you only weigh 70 kg.

What gives?

Farlo 9th December 2009 12:07 AM

You would be surprised by what some sailors can achieve. I remember Eric Thieme doing loops at l'Almanarre with 4 sqm while everybody else was hardly planing with 5. This been said, there were withecaps everywhere that day. On other occasions you can have ~14 knts of wind, which is enough for lightweight sailors to plane on small gear, without noticeable whitecaps depending on spot orientation.

Jean-Marc 9th December 2009 03:14 AM

Interesting what some image editing softwares can do to "claims" that are not supported by true and tested hard facts and evidences carried out on the water...

Planing in 4 knots wind is BS all the way, no matter what the sail size or board type is. A dedicated planing hull starts to plane at 7-8 knots hull speed, i.e., when the wetted surface is dramatically reduced to the last 40-50 cm of the hull that is in contact with water and when the hull climbs and pass over her own bow wave. Typically, there is a sudden speed surge from the 4-5 knots "schlogging state" to the 7-8 knots "planing state" when GPS speed diagrams are scrutinized by computer analysis softwares. BTW, a Formula can start and sustain the planing as of 6-7 knots of wind with no whitecaps in sight. This usually requires a 11-12 m2 jumbo sail and a lot of pumping skills.

The only explanation of "planing in 4 knots of wind" is in DTL conditions where the energy of the wave and not that of the wind actually pushes the hull to a full planing state. No big deal : surfer do that all the time in 0 wind...

Cheers !

JM

Darko_Z 9th December 2009 04:42 AM

It can be very misleading if you try to judge wind speed from video or photo. Once I took video of windsurfers in closed bay, it was offshore wind. I took measurement with wind speed meter 2 min average was 36kn, peak 45kn. But on the video it looks like the wind was less than 30kn, there were no big waves because it was closed bay. Most windsurfers were 90kg+ using 4mē sails, but this could not be seen from this perspective. Than I went on the other side of the bay where I could get light at another angle and it looked like 50kn.

Farlo 9th December 2009 04:28 PM

Hi Darko, this happens in real life as well. Presently our local lake is lower than usual. This results in irregular wind but also less chops/withecaps that you would expect for similar windspeed. Last month we had several weekends with 18+ Knts where water remained strangely quiet, apart from occasional 25+ periods. Everyone was planing, sometimes in survival mode. I guess it can happen at sea by offshore wind, low tide... Now I don't think magazines purposedly select such conditions to promote/claim planing in next to no wind.

kiwiben 15th December 2009 12:22 AM

thanks everybody, it's the original poster of this thread here (I'm not Australian after all, just used their reputation to hide my own incompetence) I am loving all your comments, keep em coming.

i was out the other day in "surging" wind of 5kts-30kts surges with one other guy and he was getting up and planing ridiculously early compared to me as each new surge started.

he was on a little fanatic 80litre B&J with a 5.2 sail. me on my 121Carve with a 5.9m sail. Only other difference was his weight, about 20kg lighter. (me being 100kg)

The good news is though, once I got up I had top speed way above him, and could haul back his 150m lead in about 600m of water. Go figure? Any comments?

joe_windsurfer 15th December 2009 06:06 AM

i don't know ...
linkin incompetence to auzzie and rockin to kiwis
ya better watch out :)

Ken 15th December 2009 09:18 PM

White caps form at 10 knots. Open water, semi-protected water, protected water - the caps still form at 10 knots, it's the size that varies. Open ocean water, the waves/swells are about 1 meter height with a 5 meter wave length. In protected water, the waves/swells could be 3 cm high with a 10 cm wave length.

This may or may not be the actual proportions, just my recollection from numerous observations and some very basic knowledge of waves. I am no expert.

The cap is a small piece of white water breaking off the top of the wave. So when you look at protected water in 10+ knots of wind, and don't see white caps, look closer because they are probably there.

Also, in protected water, the wind speed 1-2 meters off the surface may be higher than what it is at the surface, so a sail could have 10 knots of wind in it while the wind speed at surface is less than 10 knots. No caps to be seen, but the board has enough wind to plane.


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