i need to replace my main halyard due to fraying. anyone know the replacement specs?type of line, diameter, length etc?thanks

of all the line on the boat, this line means the least. use the cheapest (although light would be good) line you can find. 1/8 if your hands can tolerate it. no bigger than 5/32. go with a few feet over twice the length of the mast. I guess it would be good to have a line that doesn't absorb water too.
something like this would work...
https://store.catsailor.com/pc/viewPrd.asp?idcategory=550&idproduct=30426

or

https://store.catsailor.com/pc/viewPrd.asp?idcategory=562&idproduct=8245

I tried using a nylon pre-stretch line as main halyard once, never again. Static line like dyneema/spectra is my choice. 3-4mm.

thanks!