Is there a good reason to oversize running rigging e.g. genoa sheets

[sailingunity]

My boat came with 5/8 genoa sheets, which according to online guides is oversized for my boat length (47 feet) and way oversized for my sail size (only 500 square feet). I purchased new jib winches which will not take 5/8" line (9/16 max), so the lines need to be replaced.

Note, before I bought these winches I found some online formulas to calculate the expected clew load at 45MPH and full sail, not that I would be intentionally sailing with that much sail up, but if I got caught in a gust I'd want the line to hold temporarily. The calculation was about 4000 lbs.

Most guides recommend 1/2" line. 1/2" Trophy Braid tensile strength is 6000 lbs (a 50% margin), XLS3 is 8700 (over 100%) and StaSet is 10,100 (150%). So even Trophy Braid seems sufficient, while not as high of a margin as the other options, I've heard good things about it.

But I know there are other factors here too, such as reduction in strength due to knots and age, as well as ease of gripping the line (I even thought about 9/16 for this factor but it's only available in StaSet). That's more difficult for me to quantify, but wanting to get experience from other sailors, for a boat that plans to circumnavigate, what would you choose?

[Tetepare]

Size running rigging to the blocks and winches. If you bust a sheet you have bigger probelms.

[Jammer]

I think you would find that your sail will rip before the 1/2" sheet gives way. In the real world, lines fail from chafe not overloading.



If you're not sure get the stronger of the several lines. I think I've used all three and there isn't much difference in handling. If you're still not sure get 9/16".