I have leech telltales on my mainsail
(no luff telltales) and I understand the objective when sailing upwind is to get the lower tells streaming back all the time and adjusting twist so the top leech tell streams "most" of the time.
The question I have is, how do I know when I have the angle of attack correct on the lower section of the mainsail
? Here's my confusion: when the boat is head
with the mainsheet eased, all the leech tells stream back, but clearly the sail is not driving. So how do I set the angle of attack for maximum drive? Do I sheet in until the lower leech tells curl around the back of the sail and then ease out a bit until they're streaming back? If I'm close hauled, I never achieve this, even with the boom on the center-line they stay streaming back without ever curling around the back of the sail.
To complicate things further, I have a cat with a dual mainsheet system and no traveller, so I spend a lot of time doing trial and error tweaking of both sheets
to set the angle and twist. I just haven't found a good system that makes me feel confident that I have the main trimmed correctly for upwind points of sail.
Any advice is greatly appreciated!