I must say that this is an interesting and thought-provoking discussion. I have all the gear but have never deployed it anger (I suspect getting the parchute back might be a pretty big task since even when conditions moderate it may still be blowing 30 knots.
Couple of notes:
- I think the size of the parachute matters. You don't want to be stopped, you do want to slide sideways. We have an 18' chute for a 36,000 lb boat. This was bought by the first owner and is the recommended size for the boat. Too big and it might act as too much of a brake and increase the loads on everything.
- Jon, my sense is that being anchored and using a midship bridle is not the same, dynamically, as doing it with a parachute since the entire system - boat and sea anchor rig is free too move sideways rather than being tied to a point in space. Also, according to the pictures and diagrams in the Pardey's boat there is a considerable amount of force on the bridle so the angle in the main line is significant, reducing the ability of the snatch block to slide forward and back too much. I get the impression that the purpose of the snatch block is mainly to reduce the potential for chafe.
Finished the circumnavigation in early February in Grenada. Have to work on a book project for the next several months so the boat will be waiting for next year.