It is obvious to see. Going from 26 knots to 40 knots sees a 250 % increase in drag. This is why the record breaking boats are foiling or full planing hulls (as crossbow was).

All that drag gas to be overcome by a 250 % bigger thrust while at these angle of attackt leads to 400 % higher capsize moments. These VX40 boat were pitchpoling in 15 knots already. The are lifting a hull in as little as 6 to 7 knots, What do you think 20 to 30 knot winds will do ?

And this thrust has to be produced by soft sails which pretty much max out at an angle of attach of 25 degrees. Below 15 degrees the shape collapes unless you start using landyach setups which have done away with squaretops as you simple can't control them at these small angle of attacks. The VX40 feature very large squaretops.

The energy has to come from somewhere ; if you do the math you come out at required windspeed of at least 20 knots (and that is a very conservative minimum). Crossbow, yellow pages, Minard and even long shot (planing and foiling craft with way less drag) needed winds of AT LEAST 30 knots to break the 40 knots threshold. Why should VX40 do it in anything less ? Even the Maxi cats sustained their records in 30 knots winds or more. Any guesses as to what the seastate is at 30 knots ? Again, crossbow, longshot, yellow pages and the rest of them all made their runs on special locations with extremely flat water conditions.

And we must not forget that by far most of these record breakers were all using asymmetrical rigs and boards. I think longshot is the exception. This means that they were fully tweaked to run very fast on one tack ONLY. We all know that the VX40 is fully symmetrical. This is a serious hinderance to high speeds.

Being lightweight or not is not really an issue in these record speed attemps. Optimizing lift to drag ratios is. That is why these record attemps either use solid sails are very rigid windsurfer rigs.

It quickly becomes a problem of aerodynamics. And that is only when you have solved the hydrodynamics part first. 40 knots on a displacement hull is not a receipy for succes. The amount of drag goes through the roof. So you'll need planing hulls, bruce foils or full foiling. But even foils get into cavitation problems above 45 knots.

Enineering wise going from 26 knots to 40 knots is a major undertaking where you optimizing everything to achieve that single goal of high speed. Accepting pay off in all other areas. Areas like pointing, low wind speed, symmetry. All areas where the VX40 DID NOT skim on.

Therefor the idea of a VX40 doing 40 knots as max speed is just nonsense. I will be impressed if they do 30 knots. Using some carbon or kevlar doesn't change any of the engineering problems that took several teams (like crossbow etc) decades to solve. It is not about materials it is about hulls and rig design.

If you don't believe me then that is alright, go to college and do maritime engineering yourself for about 4 years, then spend about a decade to develop your own models and validate them with experimental data and then see whether you still believe these boats do 40 knots, just like that.

Wouter