Smaller boats require a different approach than big boats. I've rigged a lot of jacklines, measured impact forces, and published the results. On small boats impact forces are pretty low. However, the jacklines end up being really short, from the front of the cockpit to 5-7 feet short of the bow, depending on deck hatches. Any longer and there are too many places to fall off. They run near the CL for the same reason. Dedicated anchor points are required, a good idea anyway. Then a pair of hard points in the cockpit secure that area; but keep them off the floor due to tripping problems.
To move to the bow you start with the 6' arm on the cockpit hard point. You clip the 3' leg to the windward jackline, then the 6' leg (both), then move forward along the jackline in a crouch or crawling. When you reach the end of the 3' leg, unclip staying on the 6' leg, and move forward until you can clip the bow rail with the 3' leg. You are never unclipped. You also never move from 6' radius to 6' radius hard point, which requires unclipping. I've done this when the bow was seriously playing submarine at over 8 knots to windward. It's really wet, but really secure. And you can reach the whole boat.
316 SS climbing bolt hangers make cheap ($7) strong jackline anchor points. Yes, they are intended and well-test for these forces. And any anchor is only as good as the backing plate. The World Sailing breaking strength (not working load) specification for jacklines is 4500 pounds. This is in line with rock climbing gear standards. Many people are switching from webbing to Amsteel because it stretches less and because it can be made over-strength and left rigged full time (do you want to be rigging jacklines just as it is getting dark or getting nasty--that is how mistakes happen). Some cover it with webbing for better footing.
It's awkward to move the length of the boat using only hard points, remembering that they must be within ~ 8 feet of each other (one long, one short). Or you can leave a fixed tether in place at the mast. But it can work.
Make sure the clips open wide enough to clip 1-inch railings. Kong and new Wichard do, old Spinlock and Old Wichard do not.
Many examples are possible. I use a variation of this on my Corsair F-24, with the jacklines rigged along the inside edge of the tramps. Very smooth. This also allows them to go just a little farther aft, so I can use them in the cockpit. Every boat is different. And just to point out the obvious, if you use and outboard, NO tether combination should allow you to hang over the transom! Just sayin'.
MacGregor 26D
Red lines are jackline range of movement
Blue lines are are point range of movement
