Hahaha... darn... Ya, that's scary. I was trying to stay well clear of the direction it was going to fall/tip so if it did go I would have at least not been directly in the path, but I can't imagine being in a small shop while doing that with nowhere to run, not that there would be time to even react probably.
The carabiners I used had a 7 kN rating the open/closed direction, and a rating of 25kN the other direction, so while I am not going to pretend to know physics well enough to estimate a dynamic load, the rating would suggest that if nothing slipped (it did) then even on the weakest side they should be able to hold 1/2 of a thousand pound hull. Idk, maybe I am not considering something else about it though. If so I would love to hear so the next time I flip a boat I don't make the same mistake. I don't have a lot of experience lifting things or using cranes, I do have a lot of engineering math under my belt but that doesn't translate well to understanding real world scenarios for dos and don'ts.