[Bob Pingel]

I would not use wire/rope halyards, there are much better tools available today...

I have a Stevens 47 and I used 10mm T900 for my halyards. The rope has performed really well, but I do wish it was a little larger for handling reasons.

I like to spec halyard loads at 80% of peak end boom load, and then use a safety factor of 3. The Harken numbers on the Stevens are 3540#, so that would yield a required cordage tensile of 8496#.

If you are budget conscious, I'd use 1/2" stasetX

If you are weight conscious, I'd use 10mm T900

I good middle of the road might be 12mm VPC

If you do choose wire/rope, roughly 8500# is what I would design for.

Bob Pingel