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Old 12-21-2012
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Re: Wnner 9.00

Quote:
Originally Posted by monsieur bis View Post
Thank you Paulo for your reply. I agree with your analysis of the difference in hull form between the two boats. The narrow entry of the Xp 33 is readily apparent when looking at the boat out of the water, and it is felt when in the forward v berth area. It looks to me like Van de Stadt has decided to have the max beam further forward in order to allow more space for the saloon and the forward berth area. I guess my disappointment with the Xp 33 stems from the fact that it is 1320kg heavier than a X-99, a boat that I have fond memories of. I would say it would take a veritable gale to get either the Xp 33 or certainly the Winner up on a plane. From my experience, the number of boats that actually get up on a plane is much smaller than people think.

I hope next years European Boat of the Year includes the Xp 33, the Winner and the Pogo 30 in the small boat category. To my mind they are three quite different, yet well thought out boats.

Best,

Frédéric
Frédéric,the A99 was and his a great boat and a great design in its time



and it is true that was it was lighter with 2890 kg to 4330kg but the Xp 33 has more 400kg of ballast so that difference is reduced to about 1000kg. if we consider that the X33 has about more 36cms im the LWL and more 21cms of beam that diffrence is explained.

Much more than that small difference in weight is the difference in power (stability) between the two boats. Not only the Xp 33 has more beam, a more modern hull that maximizes form stability (specially downwind) as it has a hugely more efficient keel with all the ballast in a torpedo. The Xp33 maximizes even more that more efficient keel with a difference in draft (1.90 to 1.75m).

I don't think that the slight bigger B/D ratio of the X99 (44% to 40%) can compensate the difference in RM on the Xp33 provided by the bigger draft and most of all by the fact that all the ballast is on the XP 33 down on a torpedo. Of course, more 21 cms of beam is a lot (in 3.0m of beam) and that will also contribute to make the Xp 33 a much more powerful boat and even if the boat has probably more wet surface due to the bigger displacement that difference is diminished by a keel with a lot less wet area.

You can see that difference in power reflected in the sail area both boats can carry downwind, the X99 carry a spy with about 80m2 and the Xp33 one with 93m2.

Regarding planning, I agree with you in what regards performance boats heavily charged for cruising, but when discharged for racing there are some boats that start to plane with medium winds and this is one if them.

We can see on a boat test that the boat is planning doing about 15K speed with a 20K wind. In this boat with this size of hull, we can consider that 10k is already a planning speed, since it is way more than hull speed. I guess that for reaching that speed the boat does not need much wind, if it carries a large spinnaker or geenaker, and the Xp33 has just the potential stability to do that without any problem.

Take a look at the Xp33 planning with 20K wind:





Cheers

Paulo

Last edited by PCP; 12-21-2012 at 03:36 PM.
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