Slalom races in windsurfing are characterized by crazy crowded roundings of the jibe marks. Seems like that would be a recipie for kite entanglement disaster?

Yes the windsurf slalom is almost a contact sport at the gybes, but with kites, a combination of longer legs between buoys and fewer racers per heat could sort that out. You can see in the video that the protests get a bit heated.

a potential problem with the one-fin setup is that it is limited by the fin size restrictions in it's depth, and that to get the necessary area you can only increase the chord, thus worsening the aspect ratio. at which point 2-3 high aspect ratio fins might do the job better...

if there is no fin depth restriction then a large single high aspect ratio fin may be theoretically good, but the lever-arm-moment of the long fin would be large, requiring a wider board(to reduce"squirreliness") than may be optimum for all-round speed/handling.

personally I would have thought that two in-line fins would be a good setup, as it strikes a nice compromise between excessively long single fins, and multiple shorter fins, and a fore+aft fin setup is probably more directionally stable and more tolerant of varied weight distribution than two side-by side fins, not to mention easier on the backleg.
(and btw in case some people were wondering, the rear fin doesn't trail in the wake of the forefin/daggerboard, as when the fins are laterally loaded(i.e. sailing) they operate at positive angles of attack and there is a small crab/leeway angle on the board)

Ellinas,

I think that you should attend a top level race to see what is actually being done. All of the top riders in the world are using 4 fins currently. It's pretty hard to say they are dead when not even a single event has been won on any less than 4 fins. This includes the most recent Carribean Champs as well. I will say that Damo did try a 3 fin set up in once race and won, but the up wind angle was far off.

Good luck with the single fin. It may work some day, but my first race board 5 yrs ago was a single and i put quite a bit of money into testing, but could never get directional stability. You need far more cord width to keep the nose pointing in the right direction IMOP. Post some video if you get a chance. Really like to see you hammering in choppy water.

let see what the future says...

this remind me and old story of the windsurfing dvt, when riders where adding more fin to their boards (dragger fins, etc...), then one guy came with a big single fin board and rip all other oponents.

I am quite convinced that even all riders are using quad fins, they are all copying what other riders are doing. only few person are going their own way.

Armin Harich manage to complete races with the ton ten with a twintip ....

2003 Kite-board Robby Naish USA Arinaga, ESP 38.47 kts

I'm 99% sure Robby set the world speed record on a single fin directional.

http://www.naish.lv/index.php?id=7&item=2

We had a top windsurf board maker, Roberts Sailboards, make a single fin kite race board this month. It didn't work well, we couldn't get it to ride stable in the upwind direction. It went back to the shop and he added 2 more fins.


CG

Anyone try one with a weed fin? More fin rake might increase the stability.

As I said earlier, vee at the front of the board may be a solution. Windsurf course racing used to be on boards with a daggerboard, then a guy beat them on a Tiga single fin with vee bottom. If the vee was toward the front, that would help stabilise it.

Tried V in the front of one of my race boards and it made the board a death ride! the board will steer left and right without warning when the front of the board hits chop, so I definetly do not recommend trying vee. (except a small amount in the tail.)