How Long Should a Tether Be?

7-02-2016, rev. 8-8-2024

The 3' / 6' split has become a defacto standard, since these are the lengths in the ISAF standard. Well, sort of. What it actually says is that:

• 30% of the crew (or everyone if you single hand) must have a tether leg of no more than 3'.
• Every tether must be less than 6'6".

First off that means you can, and perhaps should have tethers less than 3'.

This tether is only 30 inches, is attached well in-board, and I'm well outboard. Of course, I had to climb over the high lifeline.

 At the mast in lump weather I sometimes go even shorter. How about a vertical jackline. Every boat should have these available in the form of halyards, though mine are fixed (they serve an unrelated tangle-avoidance function).

Additionally, I see no reason they cannot be longer in certain cases. My other leg is 8', bout right for the broad bow of a cat. I can imagine much longer on bigger boats. You just have to use the length intelligently.

What about smaller boats? I was fooling around on this 27' mono, using Amsteel jacklines, and concluded that the longest leg should be 3' and the shorter perhaps less than 2'. A 6' tether has no place on a smaller boat. If you would like a longer tether for the cockpit, then have a separate dedicated tether there.

I like custom sizes. I fabricate mine from 8mm climbing rope using sewn splices, but climbing webbing and knots will do nicely.

rev. 8-8-2024

The 3'/6' split is perfect for my F-24. The jacklines run along the inside edge of the tramp lacing and end 4 feet from the bow and 5 feet from the stern, and the large wing nets make it practical impossible to reach the edge. There are no lifelines, other than small sections at the bow and stern.