So glad you found it helpful. So ... in the absence of a boom vang, the main sheet is the only line that applies a downward force on the boom. As the main sheet is eased, the boom travels farther from center and the force of the main sheet becomes less vertical and more lateral, allowing the sail to pull the boom upward and form more of a belly. The boom vang helps apply a vertical force downward on the boom and contribute to a more efficient sail shape. (That's my interpretation of the traditional explanation. I'm sure others could explain it better.)

I should also add that in a subsequent outing, at the suggestion of the owner of the Boomkicker company, I flipped my Boomkicker over (the main hinge and 2 rods). This causes it to bow outward (downward) under tension instead of flexing inward (upward). The result is that the cradle becomes deeper and had more hold instead of more shallow when I sheet in and apply pressure to it. This is a better configuration and was recommended by the owner of the company. Unfortunately, I can't find the video segment where I explained that, so when I get my boat fixed that will be a subject for a future episode. :)

Correct.

Thanks for watching. Yes, boom kicker is an alternative to a topping lift. It keeps the boom from falling down when mainsail is depowered or stowed. Not sure what comment you’re referring to that conflicts with that idea. Thanks.