Is anyone running any of the larger NCXs (7.5, 6.5) on the Severne 90 RDM mast? Is it a good option for those sails?
I had a NCX 7.0 with a SDM90 this season. It was fine. Rigged nice, and went well. RDM I don't know. I haven't seen it done at our local spots by anyone. Couldn't see why it wouldn't? Should be the same mast curve? Can u try it before you buy?
i run a 7.5 on a 460 rdm 90 and it works a treat.
if anything the sail maintains a bit of curve in the entry at head height compared to
running it on an sdm. this gives it sensational low end. its almost a fake cam!
i use an blueline ally boom and the rig is amazingly light which makes it a joy to use.
on an isonic 107 i feel like i am competitive with the 3 and 4 cam guys. and perhaps quicker around gybe marks.
it really is a sweet set up and i love the lack of rigging / de rigging hassle. i can be rigged and on the water in 6 minutes which is great as time is short and im lucky to have a spare hour- including rigging and de rigging - to get a sail in these days.
and then the lack of crazy downhaul tensions and mast wear is just a pure bonus.
Sounds good. No-cams are definitely the sweet spot at the moment. I won't have anything else.
Just replaced all my cammed sails with no camm and it's the best thing I've done. Sailing is fun again and very relaxing out on the water either racing your mates around or just blasting. I believe that the current group of powerful non camm rigs are fantastic and really take the challenge upto cammed rigs on many levels. 
Hmm I do like No cams as they are easy to rig and are pretty darn good now (IE NCX,Koyote, and the new HSM GPX). But at my home spot, the differences between the the gusts can sometimes go as far 15 to 20mph:/ Koncept conditions for me!
