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Analyzing upwind/downwind angles

 
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d0uglass



Joined: 28 May 2004
Posts: 1192
Location: Bonita Springs, Florida

PostPosted: Wed Apr 25, 2018 10:18 am    Post subject: Analyzing upwind/downwind angles Reply with quote

I went for a sail the other day on my old formula board with a 9.5 Ezzy Cheetah. I zig-zagged my way upwind, then zig-zagged back downwind, as is nicely illustrated in the plot from my GPS.

https://www.strava.com/activities/1529990227

My angles were OK but probably nothing to brag about by formula standards. Just wondering if there's a reference or rule of thumb for what "good" upwind/downwind angles are for different types of windsurf craft. Especially now that windfoiling is a thing, I wonder what kind of angles they get and how they compare with conventional formula windsurfing angles, etc.

Also, if anybody has rigging or tuning tips for getting better angles I'd be curious to know. Like, do you find that you get way better angles with cammed sails? Are the latest generation of formula boards & fins getting much better angles than those of 10 years ago? Is there a huge difference in upwind/downwind angles between sailing moderately powered and sailing crazily OP'd? Are kitefoilers getting much better angles than any kind of windsurf?

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techno900



Joined: 28 Mar 2001
Posts: 2995

PostPosted: Wed Apr 25, 2018 10:46 am    Post subject: Reply with quote

d0gulass said:
Quote:
Also, if anybody has rigging or tuning tips for getting better angles I'd be curious to know. Like, do you find that you get way better angles with cammed sails? Are the latest generation of formula boards & fins getting much better angles than those of 10 years ago? Is there a huge difference in upwind/downwind angles between sailing moderately powered and sailing crazily OP'd? Are kitefoilers getting much better angles than any kind of windsurf?


I raced formula for about 10 years, sometimes against the best in the country/world. The great formula sailors were able to point maybe 3-5 degrees higher with about the same speed as me. Down wind, no deeper than me but with greater speed. The main reason was that they were on bigger sails and were better skilled at running deep with big sails. Of course, an adjustable outhaul is essential so that the sail can be flattened on the upwind and bagged on the downwind.

A few races that I sailed in had winds up to 25+ knots, where the "good" guys were on 9m sails and I was on 7.5 (scary as Hell). Racing formula requires sails that are way too large for reaching, so you need to go big to race.

Formula boards can't point as high as most single hull sailing craft, but they have much greater speed and can get upwind faster than almost anything else.

The cammed race sails are more stable than anything else in big winds, and when overpowered, so that's the norm for Formula racers. The also have a broader wind range.

I still use my formula board, but don't race anymore. I rig for reaching comfort in lighter winds, 9.2 sail in 10-20 mph winds. I weigh 170 lbs. The is a difference in fin performance and getting a good fin is important, mostly for control. I have always used a Deboichet Formula fin R13 70cm.


Last edited by techno900 on Wed Apr 25, 2018 12:00 pm; edited 1 time in total
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dllee



Joined: 03 Jul 2009
Posts: 3807
Location: East Bay

PostPosted: Wed Apr 25, 2018 11:02 am    Post subject: Reply with quote

Kitesurfers rule course racing, getting much higher upwind angles at lower boat speeds, tacking quicker, and sailing much closer to straight downwind at slightly slower boat speeds than the best Formula sailors. Not affected nearly as much by shadows, the fastest kiter nearly always wins.
Most Formula sailors under 175 lbs. use slightly smaller fins for racing in +20mph winds. VMG by higher boatspeeds with slightly lower angles seem to win. Bigger sailors can use their extra power to handle max fins. Cam sails are not only more stable, but they maintain a pocket during transitions and lulls.
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bred2shred



Joined: 02 May 2000
Posts: 914
Location: Jersey Shore

PostPosted: Wed Apr 25, 2018 11:37 am    Post subject: Reply with quote

You can't just look at angle. The critical factor in a course race is VMG (velocity made good) which is a measure of angle AND speed. I don't know what target VMG is for a formula board (maybe somewhere somebody made some polar diagrams, no idea).

Tuning, gear, and comfort level sailing overpowered makes all the difference. I raced Formula for several years fairly competitively on the East Coast back in the early 2000's and found that it is as much an "arms" race as a skill race. A prime example was one particular regatta where I was doing "OK" during the first race or two on my Select fins (what I thought were decent fins). We came in between races and Dave Kashy pulls out his stash of 20 or so custom fins he had been developing and says - here, try this one. No other changes to my kit and I'm instantly pointing 5 degrees higher and right up at the top of the fleet.

Regarding downwind VMG, it basically just keeps going up and up (i.e., you go deeper and deeper) until eventually you just explode - then it's time to rig down....

sm
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techno900



Joined: 28 Mar 2001
Posts: 2995

PostPosted: Wed Apr 25, 2018 12:07 pm    Post subject: Reply with quote

dllee is correct. At the last couple of years at the US Open at Corpus Christi, Kite boarders got around the same course pretty darn fast, and the top few seemed faster than the formula sailors. We didn't race at the same time, but putting a clock on the race, the kiters did very well. Formula went off in the mornings with lighter winds and the kites in the afternoon with stronger winds. As I recall the boards had three 30-40 cm fins. Just a guess, it's been a while since I have seen one of them.
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dllee



Joined: 03 Jul 2009
Posts: 3807
Location: East Bay

PostPosted: Wed Apr 25, 2018 12:23 pm    Post subject: Reply with quote

Kitecourse is now fully foil and foil kites, and kill Formula in angles but lower speeds. They also easily beat Formula foil, mostly lower speed and more angle. But there is hope, as Formula foil increases the sail size to approach Formula. We'll see this year.
Set up for downwind only, kites can approach 30 mph, and still go at lower angles than windsurfing.
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dllee



Joined: 03 Jul 2009
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Location: East Bay

PostPosted: Wed Apr 25, 2018 12:32 pm    Post subject: Reply with quote

Just going by past history, it took me about 33 minutes to sail to Ti cove from Lordships on freeride kit, about 25 minutes on late '90's 70cm kit, about 22 minutes [good day] on Formula, a good -3 minutes for good Formula sailors, and around 16-17 minutes for Formula foil. I'd have to speculate good kitefoil foiler making it a couple minutes quicker.
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d0uglass



Joined: 28 May 2004
Posts: 1192
Location: Bonita Springs, Florida

PostPosted: Wed Apr 25, 2018 2:53 pm    Post subject: Reply with quote

My impression was that kitefoil now has better angles AND much better speeds than formula (like 35+ kts), while I haven't been able to find any clear info on whether windsurf foil has caught up to or passed formula yet.
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dllee



Joined: 03 Jul 2009
Posts: 3807
Location: East Bay

PostPosted: Wed Apr 25, 2018 7:57 pm    Post subject: Reply with quote

The fast downwind foil kite dudes and ettes use smaller front wings, just like the slalom windfoilers.
Foil formula is faster, at the extreme angles than formula, and easier on the body.
Won't be approaching the kite foil foilers because they can't unweight.
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DanWeiss



Joined: 24 Jun 2008
Posts: 2232
Location: Connecticut, USA

PostPosted: Thu Apr 26, 2018 2:16 pm    Post subject: Re: Analyzing upwind/downwind angles Reply with quote

d0uglass wrote:
SNIP Also, if anybody has rigging or tuning tips for getting better angles I'd be curious to know. Like, do you find that you get way better angles with cammed sails? Are the latest generation of formula boards & fins getting much better angles than those of 10 years ago? Is there a huge difference in upwind/downwind angles between sailing moderately powered and sailing crazily OP'd? SNIP


Hi James, Without seeing your a polar map of your runs its tough to know how fast you were going and how high compared to current, chop and wind. Also, you are a smart cookie and likely know all that already!

No matter the gear, it must be setup for the intended course for max performance. The method for doing this isn't complex but a bit time consuming but will result in better performance if you've not actually walked through everything.

With the premise that goal number one is to go fast, the first step is to tune for speed. Comfort means confidence in that department. You must sail with as little of the hull in contact as possible. Therefore, start with a less powerful FW fin (often it will be stiffer in flex) and your mast base somewhere behind the middle. DH a bit more than you think for the conditions. Sail upwind and adjust your outhaul to balance the pressure in your feet, not your hands. If your hands are unbalanced, move the both harness lines in the direction of pull. It likely will be you move them aft quite a bit using this tuning method.

The next step is to move the mast foot forward to increase your angle to the wind. Don't let your speed drop too much; if you feel the board is getting sticky, move your booms higher and lengthen your harness lines. Now return to the beach and try reducing downhaul. Does it help? If so, great, but you must now compare mast foot settings from font to back. If not, fine, just return to your first setting and rip. The near-ideal VMG for those conditions and gear pairing is now yours.

This setting will also work for great downwind VMG. Maybe you'll find less need to dump the outhaul so much since your board speed should now be higher than it was and will keep the apparent wind more even. More lower leach tension will make pumping easier, too.

Yes, the new stuff is light years better than my old Nitro IV you bought. As fast as that was, the new sails feel much lighter in the hands, are more direct in their constant power, and handle guts with a lot more acceleration. The boards also feel less like a tank. They ride free with less tendency to stuff a rail. Far less "fighting" the gear if tuning is a bit off.

Finally, a note about stance that can greatly alter what I wrote above. As Bethwaite observed, performance of any boat (board) sailing with apparent wind forward of abeam (90 degrees) is governed almost entirely by the ratio of sail carrying power vs. total weight. No matter our weight, we can always maximize the leverage our body dimensions allow. Out and up is the key. Keep the sail upright, extend our upper body. Some sailors try to mimic the numeral 7. I think this works for some but not most. Consider grabbing the uphaul to extend the rig away. Your sail tuning might change because it now should be fully sheeted in and the airflow around it changes since the sail is also very upright.

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