Dunkerbecks record attempt with small sail?

I'm confused. Why do racers today use such large sails for racing (11.0+)but Bjorn only used (according to his interview on the Proof website) a 6.2 and 5.8 in 20-30 knot winds when trying to break the speed record. If he can go so fast on a small sail why is there a need for the gigantic sails?

Any answer would be apreciated.

Thanks

The answer lies in the angles he's sailing and the board he's riding. Course racers have a certain set of priorities. In order, ability to plane. Second, ability to accelerate. Third, ability to generate a lot of power. Forth top speed. Fairly, these are not mutually exclusive.

Racers must contend with a wide range of windspeeds, board speeds and sailing angles. That's why the Formula race boards are so wide. Downside is that the wide boards must work not only in high wind but in low wind. Low wind requires big sails to get enough pressure to point high and low. Big fins are necessary to carry all of that sail area, big tails are required to hold down the fins, etc. etc.

Speedboards are designed to sail effectively in a very narrow range of conditions-take a look at the 8-10 speedboards Dunky had at the ready. They are as narrow as possible to maximize control at 50 mph while doing there best to go fast through the lulls. Narrow boards also require much smaller sails and thus are part of the total low-drag equation.

You will observe the same concepts in slalom racing gear to a lesser degree.

-Dan

Part of it is that racers are looking to maximise their effective speed relative to directly upwind or downwind (Velocity made good or VMG), while speed sailors are looking to maximise their forward velocity.

The racers use lots of sail and fin to point high and need a wide board to get the leverage they need over the large fins. When going downwind they rely on a large sail and wide planing surface to allow them to go really deep without stalling.

Speed sailors will sail at the optimal wind angle to maximise their forward speed. That could be something like 100deg off the wind for light winds (20kts) or 150deg off the wind for strong winds (45kts).

Cheers