Jack lines where and how should I attach them

[Ian McColgin]

Assuming that the cleats are properly backed and have no other use while underweigh, I see nothing wrong with using them. Actually, that's what I do on my catboat.

There are standards for stitching a loop in webbing that you can google up and if you have or plan to make loops compliance with those matters for safety. Most anyone can tie a proper cleat knot and then you're set right and secure every time no worries about chafe in the loop and all that.

There may also be placement issues. I personally like it better when the jack lines run nearer the center line of the boat so that it's easy to set up to both reach what you want but not be even able to go past the gunnel. However, many boats, my cat included, are more readily rigged with the jacklines along the cabin house side or along the gunnel. Gotta keep them clear of other lines and not underfoot.

G'luck