Hi Martin, The C&C designs under the CCA rule such as the 43s and the 35s for instance, did not rate well under the IOR rule, especially after Peterson's *Gambare* was launched in 1973 and defined what the IOR shape was going to be. As you say, these differences included pinched ends, but also wider beams and reduced stability. Add to that the left over CCA elements in the Sail Area calculations that only counted 85% of the fore triangle and accepted 150% overlaps without penalty. This perpetuated the use of masthead rigs with large fore triangles and ribbon mains and enormous spinnakers, sometimes with overlength poles. Large spinnakers combined with reduced stability in high winds put a lot of load on the rudder and created some white knuckle steering as you continually "bounced" the rudder off stall! Exciting days!
Rob On Thu, Mar 17, 2022 at 6:56 PM Martin DeYoung <martin.deyo...@outlook.com> wrote: > Matt and Rob, > > > > It sounds like the design evolution from the 1970 43’s to the more IOR > based 1975/76 42’s the boats lost a bit of reliability downwind. Was it > mostly the IOR rewarding max beam more forward and a pinched in stern, a > increase in sail area with a reduction on ballast (SA/Displ.), or a little > of both? > > > > IIRC the 1970 43 hull design included something called a “high prismatic” > ratio. Maybe the swept back keel design makes it more forgiving when pushed > hard off the wind. It also has a fuller hull shape aft compared to later > IOR designs like the C&C 39. > > > > So Rob, what I’m asking is for something like a short study/discussion > similar to your “Good Old Boat” magazine Design Comparisons articles. The > current issue’s Design Comparison has some good CCA vs IOR discussion but > it seems the 1970 43s and 1976 42s are all IOR with no CCA influence. > > > > Martin DeYoung > > Calypso > > 1971 C&C 43 > > Port Ludlow/Seattle > > > > *From: *Robert Mazza via CnC-List <cnc-list@cnc-list.com> > *Sent: *Thursday, March 17, 2022 12:01 PM > *To: *Matthew <wolf...@erie.net> > *Cc: *Stus-List <cnc-list@cnc-list.com>; Robert Mazza > <robertlma...@gmail.com> > *Subject: *Stus-List Re: While we wait for spring > > > > So, what you are saying Matt, since I was the one steering when we went > into that broach on Burlington Bay, that it wasn't my fault! Thank you for > that reassurance 40 years after the fact. ;-) > > > > However, all those masthead rigged IOR boats were a handful off the wind. > However, I remember pegging the speedo at 20 knots on *Marauder* with the > #2 hoisted on the pole in over 30 knots of breeze during the middle > distance race in Canada's Cup. The bow wave was breaking at the > chainplates. I'd attach a photo taken of the crew at that point but know > how that gets held up for approval. > > > > Rob > > > > >
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