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Old 31st October 2009, 07:46 PM   #1
Screamer
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Default Micro sails - what board?

Hi Roger

I remember this topic appeared some time ago but couldn't find it, sorry for repeating it.
My kid is still too small to try windsurfing, but I have several mates who had this problem: micro sized sails (around 1sq.m.) doesn't seem to go very well with most daggerboards. Because of their dimensions, centre of effort isn't in the right place to react properly with the boards centre of resistance, if I understand it correctly. So how to resolve this?
1. Is there any older models that you would recommend (starboard or others)?
2. What about new Prokids Go, there is something that I don't understand on the product page: it says CENTRE FIN BOX OPTION (I suppose it acts like a mini daggerboard), but in the boards' specs the table says Drake Freeride Flow 400 S-Flex + 2x Drake Shallow 310 FRN+Base. What's with two fins?

Thanks in advance (others, not just Roger welcome to comment)

Late edit: I suppose two fins of the same length go in the middle("daggerboard") and back position

Last edited by Screamer; 1st November 2009 at 12:03 AM.
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Old 1st November 2009, 07:30 AM   #2
Roger
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Hi Screamer,
Yes, you have it right.
With the micro size sails the CE of the sail is within few inches of the mast.
The only way you can get "upwind drive" is to put the mast foot absolutely at the back of the mast box, and in many cases that still will not be far enough back.
I made a mast track extension to do some testing and I feel I proved (at least to my satisfaction) that moving the mast foot further back until it "balances" the CE of the tiny rig over the CLR of the center fin/centerboard/dagger board really improves the upwind capability when using the micro size (< 2.5 m2) rigs.
If the CE of the rig stays in front of the CLR (unless you rake it back so much it loses most of it's drive and power) the only way you can go is across the wind on a beam reach or very slightly upwind.
I have GPS data that supports these tests.
I sailed from a known point on the beach, on an Aero with a center fin, and the added on mast box extension.
With a 3.3 m2 Sailworks Retro Ripper, I could sail about 30 meters above a fixed bouy.
With a 2.5 m2 Sailworks Retro Ripper, I could sail to the same bouy, but not above it.
With a 1.7 m2 Sailworks Retro, I was about 15 meters below the bouy.
Not the most "scientific" test methodology, but I repeated the courses at least twice and came up with very close to the same results each time for each little rig.
So, if you can find a board where the mast foot can be moved back until it's over or behind the LE of the center fin/centerboard/daggerboard,you can teach tiny sailors to sail upwind quite nicely.
If you can't get the CE of the tiny rig back over the CLR of the fin, slightly above a beam reach, and lot's of complaints about getting "down winded" are about the best you can expect.
The tiny sails don't need much of an insert in the deck as they are really light. so you can pretty easily have a board "modified" by the additon of a 8mm insert (like the SUP's use) that's further back than the back of the mast box.
Hope this helps,
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Old 1st November 2009, 09:11 PM   #3
Screamer
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Thanks Roger

Very interesting tests indeed. I have a few more questions:
-I don't know what kind of insert SUPs use, can you link to some pics or explanation?
-In your test, you had an Aero with this mastbox extension, and you STILL couldn't make the smallest sail work, is that correct? So what do you think, could Prokids Go be made to work with 1m rigs? I ask because I can't try any boards before ordering.
-In your (vast) teaching experience, what is the age (or weight) when you can effectively teach kids on all points of sail?

Thanks again
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Old 3rd November 2009, 08:33 AM   #4
Roger
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Hi Screamer,
I'll paste in your questions here and answer them individually:

1/ -I don't know what kind of insert SUPs use, can you link to some pics or explanation?
I'm not sure of the "inside the board" configuration, but what shows is a simple 8mm threaded insert, ready to take the stud on the bottom of your mast base twist plate.

2/ -In your test, you had an Aero with this mastbox extension, and you STILL couldn't make the smallest sail work, is that correct? So what do you think, could Prokids Go be made to work with 1m rigs? I ask because I can't try any boards before ordering.
I'm not completely sure, but I know with a 75 Kg. guy (my size) I could not get the 1.5 or 1.7 Retro Rippers to sail very much above a beam reach. You rake the rig back and it stalls the sail.
Probably, with an insert as far back as possible (or perhaps an insert "IN" the center fin box) and some sort of "set forward" fin you could make it work.
Looking at the photo of the 2010 Prokids Go TufSkin, you can see how far it is from the
back of the mast box back to the "handle" which is probably where the center fin box option is installed.
If you had a SUP type 8mm insert installed within a couple of inches of the LE of the center fin (the plastic 31 cm FRN fins are OK, but a little larger slalom blade set forward
on a base about 50% would be alot better) I think your little ones could sail upwind pretty well with a 1.5 m2 rig.
The weight of a 1.5 is only ounces more than a 1.0, but get the lightest mast and boom you can find as those are the major weight items. Make sure the mast is only long enough to fill the luff sleeve to the top. Any mast above the top of the head of the sail is just weight (in the wrong place for sure).

3/ -In your (vast) teaching experience, what is the age (or weight) when you can effectively teach kids on all points of sail?
A motivated 5 year old can achieve this, but probably 6-8 years old is more realistic.
Until then, put a little boom on an old sail and let them stand in front of you as you sail.
Then get a big Start board and you kneel on the front while they sail with a 2.5 m2 rig.
You can help the little ones get the sail out of the water, then if they are taught to balance the rig, they can sail quite nicely, only needing help if they drop the rig.
Hope this helps,
P.S. When you get ready, send me an email and I'll explain how to sail with them, in complete control, with a "tow board" and tether system.
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Old 6th November 2009, 11:26 PM   #5
Screamer
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Thanks heaps Roger, very helpful as usual. My kid won't be ready for a long time, I was just curious, but I'll pass the info to some of my mates.

Best wishes
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