I just saw "The Boom Jack" video. Once again, congratulations! You really made it, Giu!
What is most impresive to me is that the first time I watch on of the
videos I see a bit of information that I already know together with plenty of new concepts that overwhelm me a little. And I think "Oh my God! I'll have to see it 10 times, taking notes. I'll have to download the video so I can see it in the boat while practicing... and see if one day I can learn all those concepts and know thenm by heart". Then I see it again, using the pause and going back once in a while and I understand everything and I keep going "... ahaaaa, logical, ... ok, that makes sense,..., yeah, ... ahaaa". And then if I see it a third time it all looks like obvious information that I always knew. And I must say: teaching things in such a way is really an acomplishment.
The graphics are phenomenal, the sequence of concepts is perfect to be understood. If you were a teacher your students would be happy.
In this video there is a part that I don't understand, though. You say that in order tha change the twist "you can use the traveller, if you have one, you can use the main sheet, or a combinaition of both". Well, moving the traveller doesn't add nor release any vertical tension to the boom, does it? Therefore, it would equally change the angle of incidence all along the mainsail, without affecting the twis. Wouldn't it?
Then, going further, if I don't understand that I can't undertand what you say "changing mainsail twist by changing the traveller depends on wind velocity, heel and boat balance".
Could you please explain a bit these two concepts? Thanks