Hi again,
I am enjoying this conversation. Assuming that we need to design the gear around the peak load, what factor of safety shall we use? I am assuming at least 3:1, which would mean a break load for the chainplates of at least 6 tons, and preferably more, as you noted below. Not hard to get.
It is the proof load of that shackle that is about 3 times the work load; the breaking load is about 5 times, and industrial standard.
If your cleats have 4 fasteners of .25", you might get an average break of just under 7,000lbs (see
http://www.boatus.org/findings/16/). What sizes are your fasteners? 5/8" single-braid nylon has a break strength of about 10,000lbs. Is that what you hope to use?
Fair leads,
Brion Toss