The current dark green / black masts are 4.5m long, +/- maybe a 10 - 15mm discrepancy. The old blue masts from the original windsurfer were around 300mm shorter. Only the old dacron & later mylar sails fitted that mast. With that earlier mast & sail came a longer boom to suit. From 1985 - 1986 the Windsurfer One Design replaced the original for all racing formats. A longer mast & shorter boom was needed for the new sail at that time. Whilst there were subtle differences in the sails manufactured over the past 32 years, they were essentially the same in area terms.
A sails area can be determined by several means, so there is never only one answer. Calculating one way has it at 5.72m2, another has it at 5.85m2. I can't see it ever being 6.0m2.

On an interesting note is that the very old original sail measures up near exactly the same as the current one. Maybe hard to believe but true.

The earlier mylar sails were exactly the same size as the dacron ones and were used on the blue mast. They only were around for about 18 months before the new One Design board & rig took over.

Regarding the masts you have I'm a little suspicious them being translucent in colour. The vast majority I've seen over many, many years have
been a solid (opaque) colour. They were / are made in NZ by Kilwell & generally had a black & white sticker with specs on the base of the mast.

There has been the odd exception, with one particular 'pink' mast being cited as the 'greatest thing going' for course racing. That was back in the late 80's, early 90's. I did a load test on the two at that time and found the 'pink' one was 11% stiiffer overall. Whether it was really a sanctioned WOD mast or just some cut down fibreglass 'surf' mast I'm unsure. It had quite a few different sailors race with over that time, some successful, some not.

If going to Gosford this weekend see if Pete & John can help you compare the current class legal mast to your ones, before altering yours.
Just guessing, but that 4.78m long mast doesn't seem like a proper WOD mast. Put your 4.48m one side by side with a known one and do a simple hand pressure test, or rig both up on the same sail and check its shape using the same out / down tensions.

Cheers,
Rob Howard

hi Al, I just had a look at your photos at the other thread ; that mast could be a Rotho ?