I have hoisted my boat up in the garage to inspect the c/b in its deployed position.
Yes and yes.
Does it matter a twisted centreboard is a twisted centreboard on any boat what ever type let alone Mk of Merlin rocket.
Logically if you were competitive before you knew about it you should, unless affects you mentally, remain equally competitive now you know about it. In practice I'm convinced boat speed has a huge psychological component, and if you think you're slow you will be.
My mkIX has a twisted board and it is very rapid. I was wondering whether it is twisted the right way to favour the reach at Hampton, in a south-westerly we spend a lot of time on port tack. I will have to check during the winter refurb. Uncle Mikey told us that Charge Of The Light Brigade had been built with a twisted centreboard case, he reckoned it was quicker on one tack, but it's record speaks for itself.
Does it matter what boat? Yes. A replacement for a IXb is going to be about £40 and you'll find a used one easily. For a Mk4 Winder you're looking at £400 and you need a brand new one.
Its a Chipstow tales. And I'll get a new board cos I need very little excuse to buy new stuff (except for hulls clearly).
Rod & Jo Sceptical
My 1962 BEL-1 OK Dinghy is asymmetric not only with the C'board, but with the hull. What it means is that one tack is better than the other, even regardless of wind shear, Coriolis force & all the rest. I just figure it will all balance out, but aim to make my (minor) conquests on the favoured tack.