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Mast track position and sail size on longboards
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ittiandro



Joined: 22 Nov 2009
Posts: 294

PostPosted: Mon Aug 21, 2017 9:26 am    Post subject: Mast track position and sail size on longboards Reply with quote

I sail on a WindSup( Bic) in light to moderate winds and relatively flat waters.
I know that the general rule is to position the mast base more backward for maneuverability and speed and forward for better control and directional stability, particularly when going upwind.
I wonder if the sail size should also enter into the equation, requiring a further adjustment backward or forward, particularly when using relatively large sails, like in my case an HSM 8.0 .

I also wonder if anybody has experience on this type of board and can make suggestions about how to optimize the performance, particularly for planing. I know these boards are not primarily designed for this, but I hear that people can plane them in light winds.

From what I see, shortboarders step all the way back when planing, but with windsups and longboards as long as they are, no matter how far you step backward, you’ll never be close enough to the fin and always too far behind the rig, which forces you to tilt it back..



Any comments ?

Thanks
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DanWeiss



Joined: 24 Jun 2008
Posts: 2296
Location: Connecticut, USA

PostPosted: Mon Aug 21, 2017 11:23 am    Post subject: Reply with quote

Yes: Sail size does affect mast foot location. In general, larger sails sit forward of smaller sails because the sails' centers of effort differ; the same sail in a larger size will have its COE farther back than the smaller sail.

On the other hand, a larger sail/rig often is heavier than a smaller sail/rig and the larger will push the board's nose down with more force. Sometimes a board's rocker will limit how far forward the rig can be placed. We don't want the board to plow against it's bow wave.

Your board will place in light winds but not in the way you might expect because of its reduced nose volume and rocker compared to boards of similar size. The board will slowly rise onto a plane but easily falls off if rig power drops. In other words, a reach to beam reach seems best for this design from my experience.

Try moving in small increments fore or aft. Boards like this do benefit from moving the mast foot depending on wind strength. I also suggest moving your booms much higher than you probably use them to maximize planing. A very high boom (well overhead) helps lift the nose while putting your weight onto the rig. You then may move your feet more easily when balancing on that plane.

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ittiandro



Joined: 22 Nov 2009
Posts: 294

PostPosted: Mon Aug 21, 2017 2:43 pm    Post subject: Reply with quote

DanWeiss wrote:
I also suggest moving your booms much higher than you probably use them to maximize planing. A very high boom (well overhead) helps lift the nose while putting your weight onto the rig. You then may move your feet more easily when balancing on that plane.


I get it that with a larger sail I should shift the mastbase more forward than with a smaller sail, but putting the boom overhead seems excessive to me.
I usually keep it at shoulder-height or chin height, but I once set it further up and it felt very unconfortable..I wonder what you mean by overhead...

Thanks

Ittiandro
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isobars



Joined: 12 Dec 1999
Posts: 20935

PostPosted: Mon Aug 21, 2017 3:34 pm    Post subject: Re: Mast track position and sail size on longboards Reply with quote

ittiandro wrote:
I also wonder if anybody has experience on this type of board and can make suggestions about how to optimize the performance, particularly for planing. I know these boards are not primarily designed for this, but I hear that people can plane them in light winds.

Of course, you gotta define "light winds", and it's been decades since I sailed a longboard, but I had several longboards and several successful techniques. Here are some:

Handle the sail delicately to minimize airflow interruptions.

Bear off and close the gap if close to planing.

Lift the hull off the water full length with an upward jerk of BOTH strapped-in feet (to break the surface tension) and set it down planing.

Pump.

Tune the sail to normal downhaul but below-normal outhaul for deeper draft and more grunt.

Shift your weight fore'n'aft as necessary to keep the bow from lifting too much.

ittiandro wrote:
From what I see, shortboarders step all the way back when planing, but with windsups and longboards as long as they are, no matter how far you step backward, you’ll never be close enough to the fin and always too far behind the rig, which forces you to tilt it back.


If you are planing, you usually WANT to tilt the rig aft for several reasons. I enjoyed sailing my original (i.e., long!) Malibu* with both feet in its two rear-most footstraps. That got me pretty close to the fin, but wasn't necessarily any faster ... even slower if it raised the nose.

* This is the Equipe, but the footstrap setup is similar:

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DanWeiss



Joined: 24 Jun 2008
Posts: 2296
Location: Connecticut, USA

PostPosted: Tue Aug 22, 2017 10:40 am    Post subject: Reply with quote

ittiandro wrote:
DanWeiss wrote:
I also suggest moving your booms much higher than you probably use them to maximize planing. A very high boom (well overhead) helps lift the nose while putting your weight onto the rig. You then may move your feet more easily when balancing on that plane.


I get it that with a larger sail I should shift the mastbase more forward than with a smaller sail, but putting the boom overhead seems excessive to me.
I usually keep it at shoulder-height or chin height, but I once set it further up and it felt very unconfortable..I wonder what you mean by overhead...

Thanks

Ittiandro


By "overhead" I mean that your boom should be about the top of your head (or higher) when standing on the board. Shoulder height is a low, non-racing, shortboard setup. It's about as low as anyone would ever go. Many shortboard sailors put booms at eye level. Racers use high booms to allow the board to float yet stay under control in gusts by sheeting in very hard. This sounds strange but the act of sheeting in will load the mast base and keep the board's nose from flying up. In less intense circumstances, a high boom works well to balance against the weight on the board's tail.

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wynsurfer



Joined: 24 Aug 2007
Posts: 940

PostPosted: Wed Aug 23, 2017 7:13 am    Post subject: Reply with quote

The early Bic windsups had waveboard rocker. Later models have planing hulls. Waveboards with "banana" rocker will plane, but you will need a lot of wind. There is no way to optimize such a board to plane in light wind because it is not designed to do that.
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beaglebuddy



Joined: 10 Feb 2012
Posts: 1120

PostPosted: Tue Aug 29, 2017 3:37 am    Post subject: Reply with quote

There is a specific measurement from mast base to center of front foot straps that works for getting into the foot straps while planing, Zirtaeb has it described very well here. http://www.iwindsurf.com/forums/viewtopic.php?t=32856&sid=93dcb6c664636679fe0837bfad9d9d73
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joethewindsufa



Joined: 10 Oct 2010
Posts: 1190
Location: Montréal

PostPosted: Tue Aug 29, 2017 4:54 am    Post subject: Reply with quote

xxx

Last edited by joethewindsufa on Tue Aug 29, 2017 7:35 pm; edited 1 time in total
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isobars



Joined: 12 Dec 1999
Posts: 20935

PostPosted: Tue Aug 29, 2017 2:42 pm    Post subject: Reply with quote

beaglebuddy wrote:
There is a specific measurement from mast base to center of front foot straps that works for getting into the foot straps while planing ... I think Zirtaeb suggested 22 inches from mast base to center of front straps

Where does that leave us poor schmucks who just get in whatever straps we choose at the moment, regardless of where they are, such as described above on the Malibu, just for the halibut?

Just trying to let strap newbies know that like everything else in this sport, there are very few hard and fast rules. There are many ways to get to and into them wherever they are. It's not rocket science, or millimeters, or magic, and the geometry of it all varies highly with many other factors including rider height and weight, hull shape and size, boom height, harness line length, posture, skill, confidence, sailing style and venue, and much more. If the geometry were cut and dried, we wouldn't need mast tracks, extra fin screw holes, or A-box fin slots.

I realize that many people here have very stiff joints, because they laugh at the idea of spreading their feet more than two feet apart. The rest of us have no problem comfortably spanning four or five feet ... a meter and a half ... with our feet, just one more reason there are so few fixed rules in this sport. Of the hundreds of boards of many scores of brands I've tested, only one felt like its straps were just not in synch with the hull geometry. On the other 299, I just stuck my feet wherever the straps were and went sailin'. Much of that was long before I was jibing, so it wasn't about superior skills. Much of it was also back in the day when a LOT of experimentation was going on, including putting straps on the front end of the board and sailing it backwards (the Logosz Spoon) to the Pickle Fork board with two noses. Experimentation continues in 2017, when some highly mainstream potato chip boards feel ridiculous underfoot to someone who has sailed the classic/traditional shapes for hundreds of thousands of miles.

I neither know nor care whether my front straps are 22 inches from my mast base. Besides, who's gonna move his straps just because he moved his mast base? OTOH, who's gonna move his mast base, period, once he finds his own sweet spot? (People will debate even that, proving once again that personal choice is a huge factor .)
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beaglebuddy



Joined: 10 Feb 2012
Posts: 1120

PostPosted: Thu Aug 31, 2017 3:36 pm    Post subject: Reply with quote

Well for me it was a matter of an inch or two. I couldn't get to the straps on the 11'8" Exocet windsup until I went from a two bolt base to a one bolt which moved it back 1 1/2", I made all the difference in the world.
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