Posted: Oct 11, 2012 - 07:48 AM
Is your M5.0 an XL? Does it have spreaders, substantial downhaul, and a squaretop? The non-XL used a pinhead and I think it had a shorter mast. Which sail are you looking for? Watch the luff length.
Steve Fisherkeller is right about the foot length on a boomless boat so be careful. The foot has to be shorter than beam-beam length to create outhaul tension.
You might consider an F16 main. For my 5.0XL I bought an older Taipan 4.9 main and it fit perfectly. The old T4.9 used a "short-head" squaretop (~15") due to the original T4.9 class rules so it might work on either M5.0. The original 5.0XL squaretop from 1998 had a 36" head! You could cut off the top of a used main if the luff is too long for your boat and reorient the top batten. I have a photo of the T4.9 main lying on the M5.0XL. I'll try to find it and post it.
You have to either convert the sail to boomless (bottom batten pocket and clewplate) or add a boom to your boat. The foot of the Taipan sail was the same as the factory Mystere 5.0XL squaretop so that wasn't a problem for me. To add a boom look at an F16 and copy their simple boom design. You can use an old Sunfish spar and a Hobie 14 gooseneck. With a boom you'll need to add rotation control, too, just a simple one. If boomless, you can skip the rotation overrotator. Plus, nobody makes that triangular rotator bar anymore. There's lots of little details to consider here. Forget one and you go slow.
The Mystere 5.0XL was my favorite boat (RIP...sniff...).