Proper sizing main halyard
 

I recently bought a Beneteau 381, and am in the processs of replacing the lines on board. I have formulas for a number of different line loads, but can't find one for halyard loads, this combined with the PO's selection of terrible lines throughout the boat doesn't engender a lot of confidence in replacing size for size.

I am hoping someone can recommend a load calculation formula, or a sizing recomendation for the boat.

The big rope manufacturers have sizing guides - not saying they're perfect, but a good place to start I'd think. http://www.neropes.com/LineSelector.aspx http://www.samsonrope.com/site_files...tion_Guide.pdf

Rule of thumb
 

Hello,
From tests, about 80% of the sheet load is fairly reliable.
Fair leads,
Brion Toss