Have you tried ready-rigged tethers?

In your excellent and thought provoking article How to stay on deck (Sum 16), reference is made to the need for padeye strongpoints just outside the companionway. There is a safer way of arranging things on most yachts.

Provided your boat is not too beamy at the forward end of the cockpit (less than maybe 3.5m), and you have jackstays running along the side decks, then try this… have all unused tethers attached to the jackstays, with the other end dangling through the companionway.

When a crew member comes on watch they clip onto a windward tether before leaving the cabin, they are then already connected to the windward jackstay as the leave for the cockpit. No switching of attachment point required.

Clearly they will be on the long tether, but they can change to short tether using the third clip once they are in their chosen place in the cockpit. The reverse procedure is followed when going below – keep the tether clipped to the jackstay and go down the companionway steps, only unclipping the tether from your harness when you are safely in the cabin. I have used this technique on a variety of boats from 7-13m length over 30 years and never found a problem.

It has the bonus of always knowing where the spare tethers are – they are in the companionway. The only time it falls down is when it is so rough that you need the washboard in place and the hatch shut; even then a workaround can usually be found. Kim Klaka, Fremantle, Western Australia

Coping with tides is a lot easier in the classroom than it is on the water

On most boats, tethers can be clipped onto the jackstay with the other end in the companionway

Crew coming on watch clip on from below