Wouter,
This is not a contest of which person to believe.
>On the spinnaker question: With a full size or max size spinnaker a beach cat it will develope leehelm when flying this spinnaker if the CB is located at the shroud chainplate. Your experience and many other technical people in Europe found no leehelm problem with the high aspect ratio spinnaker sheeted to the main beam with the CB located at the shroud chainplate. Looking at the two setups, I think both are technically correct for the sail geometries they apply to. I think this is the information the people reading this forum need. They do not need to hear that Bill Roberts is a misleading people or saying things that are not true.
I do not understand your motorcycle car stuff.
>As far as PNs for any boat in a race go, I cannot change them. I cannot raise the PN or lower the PN of a boat I sail. The person registering the boats is the boss. In the USA US Sailing rules apply. What I think does not matter. What was done at Tradewinds Race 2004 was the SC17 PN at 73.3 was adjusted for the square top mainsail and spinnaker for the ARC17. That resulted in an adjusted PN of 70. That was what we sailed with. I was sailing with an inexperienced crew, first time on a catamaran, and since the wind was blowing hard, we did not fly the chute. It was a total surprise to me that we won on corrected time. My conclusion after that race experience was that the boat actually sailed to a 70 PN without using the spinnaker, therefore a more correct PN for the boat might be, should be, 70 x .96 for the spinnaker or 67.2. This is only one race but based on the data at hand, this 67.2 PN could be concluded. This is what really happened and how the 67.2 PN was calculated "after the race".
The 2003 ARC17 was built in the same molds as the 1980 SC17 with the same beams and the same rudders and the same mast as the 1980 SC17. There was no new anything except for the sails on the ARC17.
>Texel speed record--- I did not know the SC Texel Race record that stood for 20 years or so was not set during a race. At the trophy presentation of the Texel Race where I sailed across the finish line first, it was announced that the ET we demonstrated was the lowest for the race so far. I was totally surprised because twice we turned around and sailed back toward the fleet for about a mile each time. Once we found ourselves confronted with a dredge pipe that went to shore that we could not sail through so we turned around and sailed out to the dredge machine itself to clear this pipe line and the second time we could not find the VC bouy in a squall but finally spotted it after the squall cleared and we had already passed the mark. Therefore we had to sail back to it to windward. Having sailed through obstacles like these and be told you have set the low ET for the race was indeed a surprise.
>An ARC22 went to France in 1992 or 1993. The owner was very excited and impressed with his boat and its rigging. He sent me a letter to thank me for the boat, which I had nothing to with--Aquarius Sails built the boat. He went on to say that many sailors from France and other countries had come to see the boat and the special rigging. They were especially impressed with the self tacking jib and many photos were made. Conclude what you may from these happenings but the next sailing season the self tacking jib systems began showing up on european beach cats with curved tracks just like the ARC22.
Every ARC product built since 1992 has had the self tacking jib system. This includes all ARC22s.
>I don't know what F18 and I20 races or data you are talking about. The Tornado in this year's Steeplechase Race beat all of the F18s and I20s on corrected time. The SC20 won the low CT trophy only because we did not register with spinnaker and take the 0.96 hit on our PN. With the 0.96 factor we would not have won. Everyone else in the race registered with spinnaker and were only able to use it about 5 miles out of a 110 mile long race. They paid a 4% CT penalty and only used the spinnaker for 0.5% of the race.
>Wouter, all curved tracks are not equal. A slightly curved track like the ARC22 will work mechanically just like the straight track. Only one control line required. The extreme curved track, curved to the radius of the foot of the jib, does require the separate control line to position the jib traveller car along the track. A track bent on a radius greater than the length of the foot of the jib does not require the traveller car control line because it has a delta L/delta theata term greater than zero when the car moves to leeward and this causes the car to come to rest in a force balance situation. When the traveller track radius equals the radius of the foot of the jib, the delta L/delta theata term goes to zero and so a separate control line is needed to position the jib car along the track.
I'm tired of this. Let's move on!
Bill
