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lydia said..
Show me a real Ct with an AVS of over 140 for an S&S 34 please.
Think you will find most are in the low 120s.
A Currawong is about 119 or a bit higher AVS, Ramona should have an IMS ct for that.
Also there two separate concepts here, righting moment and AVS.
Righting moment equal speed, hence 100 foot canters, max righting moment and minimum weight.
AVS is simply the angle where the boat no longer wants to go upright but would rather go upside down.
Also the S&S 34 is not actually an IOR boat but a CCA boat and don't have that much righting moment.
In any event when they did well it was before IOR Mark 3 (about 1972)
By 1975 it was all over for them.
I can't vouch for that AVS, it is a figure often used by owners and it obviously varies with each boat. Alex Whitworth and Alan Fenwick have used such figures with me. I'll chase up someone who has a proper AVS calculation.
The following is useful support for a 140 degree AVS.
There is an account here from Alex Whitworth that his Brolga 33 had an AVS of 136 degrees.
https://reader.bookshout.com/reader/9780071813198/previewThis link notes an AVS of 150 degrees not being uncommon on older boats.
https://reader.bookshout.com/reader/9780071813198/previewSome very interesting information on boat seaworthiness and stability by reading the full link.
Anyway, irrespective of the actual AVS my point is that the S&S34 is an extremely stiff boat with a high ballast ratio (2480kg 6ft deep keel on a 5500kg boat), strong righting moment and high resistance to capsize. Irrespective of the actual AVS figure (varies by boat anyway), the S&S34 is a very stable boat and yet it rated well in IOR. It seems that high stability did not disadvantage them.
PS. Interesting that it was all over for them by 1975. Huckleberry did very well in the 2007 S2H (28th overall, 3rd Div E) as did Azzurro in the 2015 race (3rd overall, 1st ORCi4 - and a bit of wind in the Derwent she would have won). A bit earlier in 1993 Marrara came 3rd overall. Blondie, a new S&S34, was winning everything in the west. In the right conditions, strong headwinds, they still do very well.