Hmmm... I'm considering beefing up my topping lift to 1/4" specifically to
support MOB recovery using the boom. I hadn't considered the sheer force
on the gooseneck, but, with the lifting tackle attached near the end of
the boom (maybe right at the topping lift attachment), and the boat heeling
with the weight of the MOB, I'd think the vast majority of the force would
be straight down. That downward force would be taken by the topping lift,
not the gooseneck. I'm very curious about your experiment with the spare
boom.
> I was talking to a girlfriend of mine with thirty years cruising experience
> yesterday. She has a 4:1 block and tackle on a heavy-duty velcro strap that
> she keeps in the cockpit. (It's like the one sailmakers give you for the
> clew of a loosefooted mainsail; you could hoist a grand piano with it)
Correct me if I'm wrong, but lifting my 225 lb self with a 4:1 arrangement
would require 56.25 lbs of force, right? We experimented this weekend with
the mast raising tackl, which gives 3:1. I secured one end to an overhead
tree branch and the other end to me. My wife tried to hoist me off the
ground, and had a difficult time of it. The 3:1 purchase would have needed
75 pounds of force. I'm going to rig a 4:1 to see if it seems good enough
for her, but I think 5:1 might be the way to go.
Of course, the triple block with cam cleat needed for one end of the 5:1
system is not cheap. If 4:1 works well, I'm may just get one of those
Garhauer vang kits for the purpose.
-- Eric L. Pederson P-19 #970, Necessity Bloomington, MN