Further to this topic-
www.seabreeze.com.au/forums/Windsurfing/General/How-to-take-batten-out-of-cammed-sail/ I use a severne blueline 430 mast SDM.
The batten above the boom won't rotate- too tight. We've taken the cam out and filed it a bit so the batten goes in further but that is limited as any more filing and you'd use the lip that stops the batten..As you can see I have no batten tension and yet it won't rotate properly - stiff as hell..
What sort of cams do they have as default? Are there supposed to be 2 types? The boom height one is like this below - big with rollers and rotates well ( except the batten is too short and was broken so that"s a separate problem I will fix).Note how the cam isn't sitting up to the batten- is it normal for that to happen when the sail is loose ( no downhaul / outhaul..) This is one of the reasons why I got into trouble judging what length to cut things..- I didn't realise it was like this with that gap. I pushed it on properly earlier but you can see its come off again..

Closer pic last one..
The problem one above the boom ( won't rotate- too tight) is this below ..
Just about had this- if It wasn't for the fact that it will be such a great sail fixed I'd chuck it..