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Fin Works Chart -82K
Fins are the most overlooked bit of windsurfing gear. Most windsurfers know the importance of good sails, masts, and boards, yet the right fin can have as much or more effect on performance at a fraction of the cost. One should have a fin quiver, changing the size and style for different conditions, just as with rigs. A board can cover more wind range this way.
Fin Works makes the highest quality production race fins, the PRO Series. Now this quality is also available in a "free ride"design. The new FSpro is a line of fins for bump & jump, and fun slalom sailing where the emphasis is on speed and turning, rather than pointing upwind.
Weeds are a drag, literally, and the best way to deal with them, short of a lawnmower, is a good weed fin. Fin Works has the fastest and best balanced, and soon in a larger size to go with the new super giant slalom boards.
Wave sailing might be the best thing in the world, and it's even better if your wave fin works for, not against you. The new Fin Works wave fins have the loose feel you need in the surf, but with better top end speed for big jumps, and better pointing for onshore conditions. They are perfect for the new generation of "convertibles" as well as traditional wave boards. There's also the Fin Works Wave Blade series for bump & jump.
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Fin Works Chart -82K
The first rule for fin selection is that if you are using a bigger sail, use a bigger fin. Naturally one wants to balance the two forces. Fin Size is often given in length ( inches or cm ) but since fins come in different shapes, length is good only for comparisons of the same styles of fins. A 12 inch weed fin is actually 'bigger' than a 14 inch slalom fin in terms power. For this reason area is a better indicator of a fins size, and the size of the sail it will work with. A very rough formula for figuring what size fin you need is to multiply the area of the sail ( in square meters ) by 50. This gives a midrange fin area in cm2. This is only a starting point. The board size and style, rig type and tuning, water conditions, sailor ability and style, and the kind of windsurfing being done will all affect the fin size and selection. Fortunately, one can usually just check the manufacturers chart for a more detailed recommendation.
Boards will usually cover more wind and sail combinations than their stock fins permit. Of course there are limits - a big fin won't make your 253 wave board work with an eight meter sail. The limits are mostly volume, rocker line, tail width, and footstrap placement. The wider the placement of the footstraps from the centerline of the board, and the wider the board itself, the more fin it can handle.
The fin shape presents another set of variables. The most important are the aspect ratio - how narrow a fin is relative to length, and the template - straight up and down, or curved back.
A vertical fin goes faster up wind and planes sooner, while a raked back or swept shape improves high speed control and tracking in the turns. A narrow blade is fast, but more critical, while a wider one has more low-end power. For this reason, a slightly fatter than average fin works better on longboards and for marginal conditions. For slalom boards on a plane, an aspect ratio of about 4 to 5 is best for most conditions. Wave sailors aren't so concerned with top speed since they won't go in a straight line long enough to reach it. In waves it is important to have a wide range of power and good control on all points of sail. Wave fins are swept back, and have an aspect ratio about 2.5. Bump and jump is sort of a cross between slalom and wave performance, so the fins are a cross as well. The a.r. is in the 3 to 4 range, with more rake in the tip than a slalom fin, but more vertical than a wave.
Weed fins have a steep angle to let grass slide off. This costs some speed and pointing, but beats trying to sail with a glob of weeds on your fin.
Boards have different style of bases, with most of the recent models using some type of through-hull design for strength. There are adapters available to convert one blade to different style bases, but this does compromise strength somewhat. Adapter bases are not recommended on fins 40 cm and longer. You must buy a fin to fit your board, but the pros and cons of the most popular fin systems are listed here.
Base Types
A and E boxes are the oldest style. The fin is mounted from the bottom. The two systems look the same, except that the E base is a little deeper. They are weak, but offer adjustment, so they are still used on some wave and convertable boards where strength is less important than exact fin placemant. Widely used on older boards. |
Tuttle is the original and strongest of the through hull systems. It uses two bolts from the top. Found in many custom and race boards, especially in larger sizes. It is well suited to the high loads created by big race fins. |
Powerbox is the system used by Mistral and F2. It is a through hull box with a single central screw. It is not as strong as the others, but adequate for mid size fins. The fin is not as firmly mounted either, so the fit must be more exact, but it is convenient to change fins via the single, lever operated screw. |
Trim or Power Trim is the Bic and Fanatic box. It is the only through-hull box where the fin position can be adjusted. This can be a big help to fine tune the handling of a board. The fin is held in by a tab and one screw, so it is easy to change fins, but more secure than the Powerbox. |
Tiga created it's own conic system, with two bolts at first, then a horizontal pin in place of the front bolt. A very strong and convenient system, but not widely used. The newer Tiga fins work on the old 2-bolt boxes, but the old fins must be modified to fit the new boards. The 1998 Tiga FreeR boards use the Trim box instead. |
Other fin systems exist. Old Windsurfer brand boards had a proprietary box that is no longer used. Magnum boxes are found in a few custom boards. They are like a 'heavy-duty' E-base. Some wave boards use side fins which may go in one of three different surf board boxes, a shortened A-box, or even be attached permanently to the board. Fortunately these odd-ball systems are few and far between. |
Fin materials vary depending on cost and application. Plastic was once prevalent, but since it is weak and soft it is not suitable. Fiberglass was next. It is easy to work and inexpensive, but heavy. It is still used, especially in wave fins, It works well in lower aspect designs where great strength is not needed. G-10, an epoxy laminate, was originally created for electrical circuit boards, but is now widely used for fins. It is low cost and easy to grind into shape. It has a flex that gives a nice feel to mid-sized fins. Drawbacks are a lack of consistency from batch to batch, fatigue characteristics that may shorten the useful life of larger fins, and weight, which is fairly high. Carbon and carbon composites are light and very stiff, so they have been used in fins, but there are many drawbacks. Carbon is very brittle, so it shatters on impact, it has a high cost, is hard to finish smoothly without heavy coatings, and is too stiff to ride well. The best fin materials are probably those engineered specifically for the job, such as the Profoil VTR used by Fin Works. By molding, rather than grinding, a very consistent shape is achieved. Because fiber composition and orientation can be controlled, it is possible to optimize flex in all directions. The high fiber to resin ratio produces a stronger, lighter, and longer lasting laminate with a smooth finish.
It is not much use to have an expensive fin if the foil is rough from dings and scratches. Even a little nick can cause drag. Keep the foils in good shape, use sandpaper as needed to remove small dings. The front should be rounded slightly, while the trailing edge should be crisp, but not dangerously sharp. A 400 to 600 grit wet-sanded finish is best. New fins should be scrubbed to remove mold compound. Never wax or polish a fin, as too slick a surface can cause spin-out.
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