Imax1 said..RichardG said..Imax1 said..Ready to take out of retirement .
Back strap moved forward 6 cm , nice wide stance for oafy me front straps . I thought this would be OK because the boards rocker is so flat so far forward and is quite a long board .
New deck pads and straps and sugar coating.
The last time I rode a board this narrow was about thirty years ago and thirty kg lighter . ( 57 cm )
Can someone tell me the biggest size sail i could use on this thing , im presuming its not a 9.4 in 15 kts ???
Was a old tuttle , now a butt ugly 34cm US box.

The fin looks cool as does the deck modifications. Perhaps a 7.5 m2 as per Grich62. Where is the finbox in relation to the straps ? I would be interested to hear about your feelings after sailing the board as I would have expected the original straps were in a good position relative to the fin but I guess you will have enough age enhanced "leverage" at the back end to make the engine room of the tail work.
Yeah , the tail is quite thin and pinny. The rest of the board is 10 cm thick and boxy . It's got a long finbox . As a guesstimate I'd say front of finbox middle of the new back strap . Looks good to me.
Original straps position for a 80 kg pilot with a old hang off the back sail seems like a good position .
Im using new sail and I'm fat

7.5 ish is around 20 to 25 kts for me . That's kinda what I'm thinking.
If it's a real solid 25 + I'm thinking 6.5 ?
I think originally it would have worked well with 4.5- 6.5 m2 sails. Now with modern sails they are lower aspect and leech twist off. Hence yes 5.5 to 7.5 as you propose as modern sails have a wider range better top end but not as good low end as older sails.
I added the following to my original comment for what it is worth:
"You might find the wetted surface of the board has increased by using footstraps further forward and this might be an issue and the back straps as originally designed would unwet the planing surface.
Mast track-The board likely has a mast track/base forward from boards of today. The board is great and it is "old school" and based upon a "high aspect" sail of the late 80s/early 90s. That means the mast track was placed with this in mind. High Aspect sails means taller with a shorter boom. Modern sails are shorter with longer booms. You may or may not align properly on the board with modern sails.
Using a new sail I would have used high booms for the mast forward position to address the modern sails. That could be done even by slightly extending up the mast extension up a bit to do so. In this way set it up to adjust the rig geometry for the original further aft straps with modern sails given the wide point of the board and maximum volume are further forward than it is today.
That may not be an issue and you might find it all works fine as you have modified it."
Good luck Imax1 you have shown incredible talent and craftsmanship in your work to date.