By keeping the tweaker tight, you are closing the leach, especially at the top 1/3 of the sail. So you are doing exactly the opposite of what you claim. I want to open the top 1/3 of the sail rather than close it.
Very cool video showing how tough those boats are, and why I so badly want one.
First, it looks like the bottom of the chute is fairly level, indicating they have the sheet tweaker down. The sheet tweaker must be let off completely in these conditions to add twist to the chute and spill wind. The chute should be treated just like any other sail in this regard. I have a feeling that this was the main cause of digging in to the water.
Dude it's not April 1st yet. Are you smoking crack? Are you anti-French or something? Twings down to the deck, sheet on the edge of eased, and ready to be dumped altogether in one hot instant. The last thing you want is a wobbly spin up high, you will death roll like crazy. Come on, you know that. And for this exact specific thing -- pitchpoling in high wind and seas -- as a matter of basic physics you want the CE of the chute down as low as possible.
I can't believe some of the total crap I read on here. I don't know how to upload the palm-face picture.
I have little experience with these boats and in this wind and don't want to pretend like I do but I agree with clam, it seems like the tweaker would help to stabilize and "flatten" the Spin?... If you let the tweaker off I would think your not going to be spilling wind at the top but quite the opposite and deepening/powering the sail up high.. I apologize if I'm comparing apples to oranges but especially if you are comparing the spin to any other sail like you say, you can think of it like Vang-sheeting the main as you would on a Laser in high wind. Crank the Vang on to help flatten the leach and keep the power lower in the sail and then when you ease the sheet your actually spilling air and not deepening the sail high up.. Can you compare the two?