Some of the boats for sale at winder 2 when the hand book says winder 1. Does this mean they've been modified? Is it possible to check?

See the design guide :)

Mk2 stares at 3604. Only significant change was a bulge keel reshape 

I think we should get rid of bulge keels :))

...and stop staring at 3604!

Ah I was going by the year book which had them down as 62WBfs(MK1?). I thought the MKII was a 72WBfs

But looking closer I can see it jumps straight to 72bwBfs which is the 4.

...and stop staring at 3604!

Not sure how that happened?

Fear not all, I spotted this about 6 months ago too and have updated the YB accordingly. This and a few other corrections from historic editions will be winging their way to you in the coming weeks... always nice when the eagle eyed among you spot a correction as well as a mistake! :-)

PS, it should be noted that the Winder Mk1s should be "62" as they were indeed an original Canterbury Tales design, it wasn't until the Mk2s that there was Winder involvement (as per the modifications between the old and new designs), hence the Mk2s are 72s, and things then progress from there through the Mks...

It's also worth noting that at least a couple of the Mk1 Winders have been modified to the Mk2 or Mk4 shape.  Mike Mackie is particularly quick with 3580, a Mk1 upgraded to Mk4 specification.

Hi Dave,
You're right on that with the bow drops, etc. My take on the YB is that it is meant to be a record of how and when boats were built, and so mods are likely to happen without necessarily being recorded... Frankly, it can all get somewhat confusing! 
I also think that given that so much development has taken place in rigs and systems over recent years, we're only really recording part of the fuller picture. And that has always been true. If anyone has strong view on how this should all be achieved though, then I'm sure vacancies for this type of job would spring open very quickly!
Tim 

Actual hull shape change did not take place until the Mk4 when the stem was lowered. The only changes in the Mk2 were a fair up of the mould and a change to the bilge keel profile. Construction changes began to appear as an option in the form of carbon forward structure at 3604 but these were very late Mk1s. A Mk2 will be 62 in the year book, 3607 was actually the first one.
 
I think most Mk2s have now been altered to the Mk4 shape and many will also have been one string upgraded. This stems from the time when a Mk4 fully kitted was very much more sought after and expensive secondhand than a Mk2 or Mk1 and it was economically viable to upgrade the existing boat. The Mk2s were especially good candidates as most of them had the carbon forward structure and faired bilge keels already.
 
My info says the one string system appeared at 3627 as an option and it became standard fit out very quickly. I'd say all of the few Mk4s supplied without it have been upgraded by now, there can only have been 5 or 6 to begin with.

How to check:
 
The bilge keel change is obvious. If there sticky out and rectangular then they've not been changed, if theyre faired in and very round and flat it's been altered.
 
The bow change is more subtle.  I don't have the measurements but if you measure the length of the stem on a Mk1 and Mk4 the 4 is about 20mm deeper. A trained eye will spot that the third plank up from the bottom (The plank above the really narrow one) is wider on a 4 than an unmodified mk1 or 2. 

Good spot, according to my year book which is a few years out of date, no winder 2 or 3's have been built. And it does appear two mk1's are for sale as mk2's. They may have been modified but I think they should still be mk1 with listed mods.

In terms of the hull shape I know there was no change between the Turner and Winder boats but didn’t the centreboard move forwards, due to the change to longer poles?

The mk2 was never classed as a new design. It will be 62 in the yearbook. First built was 3607.
 
The Mk3 never existed, there was a quirk in the measurement rules at the time that only permitted 10mm adjustments. They wanted 20mm so did but twice giving rise to the jump from mk2-4