Hi Ola H.,
In your comments above, you raise an interesting point about a sail tending to "fold" in its mid part due to sideward bending. In my earlier post above, I was remiss in not noting that my comments were relative to use of SDM masts. While have 2 Gulftech RDMs (430 and 490cm), at this juncture I haven't yet logged much time on them. Also, the two newer sails that I match up with them do not require too much extension.
In any case, I wondered whether the folding phenomenon is as pronounced with SDMs as it is with RDMs. I know that RDMs perform a bit differently due to their geometry, so it is my thought that SDMs might be less subject to folding due to their larger diameter base and mid section. Any thoughts?