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Old 2nd June 2011, 11:08 PM   #31
mark h
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Basically at this stage, the footstraps in or out dont really make to much difference. Set inboard will be more upright stance for tricks, gybing etc and easier handling in rough seas. Outboard setting more locked down stance for speed and leverage against the fin. You should try both settings and see which feels best
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Old 3rd June 2011, 01:25 AM   #32
Farlo
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Hello Mark, can you explain again the deck plate trick? I thought that pressing on the front foot would help to go downwind, thus the mast track forward and/or lower boom. Personally I feel much better downwind with a smaller fin, but that's not so much the question: 42 sounds quite large for 6.2 and 5.0 sails, notwithstanding shallow water.
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Old 3rd June 2011, 01:49 AM   #33
nicolo.piccolomini
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mark, so i have to put the mast back? i thought you had to put it forward (makes more sense!). and foostraps backward as well?
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Old 3rd June 2011, 01:50 AM   #34
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and btw, as soon as i get the opportunity i will check my fin, because i think it IS 42cm and you are right it is supposed to be a 39cm.
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Old 3rd June 2011, 03:32 AM   #35
nakaniko
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Very nice board; as I've had for many years F2 Wizzard 125 litres, design Peter Thommen, seeing your board seems to me to see something of the very nice shape of mine, surely your is much better for materials and construction. From description the board should be great for Talamone conditions, it's described as a board that has no fear of cruising through rough water conditions.
Since first posts I had some doubt that the upwind problem could be caused by the long fin itself. save you money and get a lesson, TWCK school is on the beach, or from expert friend. And so save you fingers in cutting the fin...
On the opposite I disagree with you when you want to keep only ONE fin for all the wind conditiions.
Think at your fin like the "underwater sail" that obviously has to be properly sized according to the sail.
I'm 85/90 kg, In Talamone I had days with the Wizzard with 12-14 knots, then using 8,0 sqm with Select Course 48 cm, days with 15+ ktn using 6,5 and the stock 40 cm or a Prolimit 38, but days with the 5,3 then going down to a 32 cm fin in 20+ knots. Most of them bought on sale for 30-40 euro each, even if new and good branded. Some day also with 4,5, 28 fin, 25 ktn. So pheraphs 42 could be your bigger fin with about a 7,2 in lighter winds, with more wind some smaller fin could help to find the correct balance and not wasting strenght to avoid tailwalking or other side effects.
When you change size of sail should be normal to use the correct size of fin. Having the fabolous powerbox you can find on ebay.de even more cheap good fins then previously suggested by me in another post, when I was thinking at a TU box. They usually fit almost always perfectly in every powerbox fin- Pay attention that fully planing with a 42 cm and a 5,0 in strong wind and rough sea can be a nightmare for your ankles, I've experienced it a lot of times, can even be difficult to come back if not experienced.
As you're so good in languages for your age, I hope you can understant the fin explorer of www.whitewatersurf.de that can give you an idea of different fin sizes according for your weight and conditions (use flachwasser=flatwater freeride). If for smaller sails the result is highlighted in red and only KEIN etc., it means that for your board that sails is too little and out of range and so no fin to suggest; don't worry, select a smaller volume.

Last edited by nakaniko; 3rd June 2011 at 03:36 AM.
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Old 3rd June 2011, 04:21 AM   #36
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Like RSX and race boars with sliding deck plates, mast track forward (to engage more of the leeward rail and easier to rake the sail back) on the upwind legs and slide deck plate back on the down wind legs (to reduce the wetted surface area for extra speed). Speed boards for instace, generally have deck plate pretty far back for extra speed (speed boards are for broad courses). High boom also improves upwind, lower boom allows for a better stance when going broad.
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Cheers - Mark H

The toys:
iSW44 - - iSW49 - iSW53 - iSW58 - iS107 - iS137 - F161.
North Warps: F2012 5.2m, 5.7m, 6.3m, 7m, 8m, 8.6m, 9.5m F2006 11m.

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Old 3rd June 2011, 05:03 AM   #37
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Cool Conundrum

FAO Ken

All you say is (nearly) correct and obviuosly wide boards will support bigger fins and not just because of the extra leverage available to hold fin in (more or less) correct place.

Stick a really big fin in a narrow (ish) board with a smallish stable sail. You wont have problems (like you say) until

a) going (relatively) fast. At some point board will start luffing up. Even with a stable sail which is not going back handed !!! Fin is producing more lift than sail is producing side force. (ie down wind vector of forces)

b) Going relatively fast you WILL have difficulty bearing away even with the stable and small sail !!! Why ? Same answer as a)

c) Persevering and going faster will try and rail the board. (ie Fin is producing rotation of board because of eccentric thrust of fin; normally countered by sailors weight on wide rail. (Its why cutouts work; wide board but relatively low surface area)

d) You will also have problems gybing a narrow board with a big fin. Why ? Extra drag of fin needs the planing ability of a wide board. The narrower board will literally drop off plane and sink tail; where a smaller fin would allow board to maintain planing because of less drag.

Seriously Ken. Go out and stick a 48 cm fin in as 63cm (ish) wide board and experience being severely over finned. You will change your mind. The board WILL luff up; it will drop off plane in gybes and it will rail !!! Even when not overpowered !!
I have big(ish) cammed sails in my quiver that just do not get overpowered (they just produce too much power;which is different. I`ve sailed a 5.8 cammed North in 40 knot gusts.(last years Defi) With a big fin it would be impossible; with a little fin I can hang onto it in stupid winds without problems bearing away;luffing or railing..
Infact this season I`m plannig on always competing with smallest possible fin !!! My Vmax is better and if I can maintain boardspeed in lulls (with bigger sails and better fitness) I can still fly upwind. We`ll see.

Fin choice is a bit of a conundrum. We assume its linked to sail area;which it is but only indirectly. Fin choice is much closer related to board speed irrespective of sail size.
For example in 6.8 (cammed) weather for me at 105kg my expected board speed in a race would be 30 knots or so. I`d get away with a 34 cm fin. My sailing buddy (at 75kg) on same board and rig would be using 6.8 in less wind and subsequent slower board speed (ie 25 knots or so) consequently he`d be on a 40cm or so ??? Which is sort of opposite to expected ??? ie same rig/board. Lighter sailor but bigger fin ???? (but less wind !!!)

Fin size is directly related to board speed.Rogh water; slower speeds bigger fin.

Think we`ll have to agree to differ !! Come down to Leucate this Autumn and we`ll sort it on water !!!
Take care !!

We dont yet understand exactly whats going on with fins. The theory on land doesnt yet quite explain everything we find on water ! Its why sport is fantastic and still developing....

Other conundrum about fins is this !!!

Fin will only work if board is subject to leeway;it needs leeway to get an AoA on both tacks. Leeway is the very thing fin is tryiing to overcome !!! But if it overcame it it would produce no lift against it !!! ??? (Load fin on a dead run; it spins out immediately !!! Think about that for gybing !!!
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Old 3rd June 2011, 05:08 AM   #38
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Cool Tail walking

PS
Tail walking is not caused by fin !! Its caused by excessive lift of hull;its why cut outs work.As board goes faster it has to plane on smaller and smaller area to balance load. Tail walking occurs when hull lift exceeds load.
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Old 3rd June 2011, 12:22 PM   #39
nicolo.piccolomini
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ok thank you. so, in conclusion, what fin would be best for me for my 5.0, with a 130lt (67cm wide) board and 75kg weight (i really can only afford one)?
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Old 3rd June 2011, 02:40 PM   #40
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A 30cm would be right place to start.
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