Safety tethers. Why webbing?

[twig]

I have thought of using the unused spinnaker halyard and tie on to it with a prusick as a safety line. I realize I'd have to flick it over the spreaders to go past main. I could adjust prusick to keep it at just the right height. Any thoughts.

[thinwater]

Responding to a few comments.

1. The book I referred to ("Single handed Sailing for the Coastal Cruiser") is here. You can also search my blog, although the math and details are in the book. Sail Delmarva: The Book Store

2. Corrosion is an issue with many locking biners. The Kong Tango however, is well-proven. Wire gate climbing carabiners are great for non-tether, utility uses; they are practically corrosion proof, lighter, better QC, and much easier to use than marine biners.

3. The CE drop test very closely models the worst-case throw if the sailor is clipped to a hard point. On the jacklines, of course, the impact will be less.

4. Talk of non-stretch jacklines needs to be very carefully considered. The strength standard for jacklines was based on experience with polyester webbing, and if steel or Dyneema are used, the forces on the jackline are much greater, exceeding the design values. I think they are fine, but they need to be engineered stronger, since there is less shock absorption. I have published the math and test results on this.

5. The ISAF has been World Sailing for several years.

[thinwater]

Originally Posted by twig

I have thought of using the unused spinnaker halyard and tie on to it with a prusick as a safety line. I realize I'd have to flick it over the spreaders to go past main. I could adjust prusick to keep it at just the right height. Any thoughts.

I tested that because I was asked to. It is perhaps the most dangerous method ever suggested.

1. It will tangle in the spreaders.
2. Length changes as you move.
3. If you fall you will swing over the rail and hang about 10 feet to leeward (the masthead is not over the deck). If singlehanding, you are truly cooked.
4. It increases your chance of falling by sweeping you off your feet.

Honestly, crawling is easier and better than that.

[Cheechako]

Even with a lifejacket tether, if you are sitting in the cockpit, your non flat one may cause a fellow sailor to roll on the rope.

[thinwater]

Originally Posted by Cheechako

Even with a lifejacket tether, if you are sitting in the cockpit, your non flat one may cause a fellow sailor to roll on the rope.

I use rather slender rope for this reason (8mm = 5/16"). It is no slippery than webbing. 1/2" rope would be a problem.

I would love it if a shock-absorbent, strong webbing existed. To my knowledge, it does not. I relatively low stretch of nylon webbing is an artifact of the weave, and my old ribs like more stretch.

For me, this is a non-issue, because the boat is a catamaran (changes the layout), is center cockpit, because the tethers stay stretched out of the cockpit, and because I mostly singlehand. Tethers in the cockpit are always a challenge.

----

On the topic of impact, try this expereiment:

1. Put on your chest harness.
2. Create a rigid anchor to a large tree or piling. Like a cockpit hardpoint.
3. Attach your tether with 6 feet of slack, and take a running fall at it, backwards. Actually, don't do this, because you may be seriously injured. The shock can break a rib or damage your spine. It's happened.
4. Now try that with 8mm climbing rope. Not a bruise, not even pain. The rope stretched 6 inches.

I don't think this is an exaggeration. I've taken cross-deck stumbles like that.

[Captainv40]

Contrary to everything written about jack lines, I have found webbing to be dangerous on wet decks, as even when set up tight it will slide enough underfoot to cause loss of balance. Round line can be felt underfoot and thus is easily avoided even in the dark. I run low-stretch lines fore & aft from bow to stern pulpits tight along cabin sides, and clip on to those (as well as one across the cabin top just forward of the mast).

Been using this system for over 15 years and 30,000 + sea miles without problems. Harnesses in general are a PIA. I can only remember one time long ago the one saved my life.

[MarkJ]

Originally Posted by Captainv40

Contrary to everything written about jack lines, I have found webbing to be dangerous on wet decks, as even when set up tight it will slide enough underfoot to cause loss of balance. Round line can be felt underfoot and thus is easily avoided even in the dark.

I agree.

[thinwater]

Originally Posted by Captainv40

... I can only remember one time long ago the one saved my life.

I assume everyone recognizes the strength of that understatement.

I can't say as much, but I know I have bumped into them, leaned on them, or just plain impacted them countless times when landing big fish or testing gear (drogues etc.) with the gates wide open. In those cases I would have behaved differently and worked slower had the tether not been there. The tether was an important work aid, in adition to being a safety tool. So from my point of view, although they can be a PIA at times, they can also make work easier and more efficient, since you can just get to it.

No, I don't wear one all the time. Not at all.

[LeeV]

I can't recall the jacklines/tethers I used years ago aboard the Pride of Baltimore II, but we use webbing on our boat, and on our trip from the Chesapeake to M. Vineyard a year ago we never had any issues, and we faced some rough seas. They were also a blessing when we hit a shipping container under the surface on the return trip doing 8 knots and it stopped us instantly.

If it ain't broke, I won't fix it.

[thinwater]

Originally Posted by LeeV

If it ain't broke, I won't fix it.

If that were actually true, wouldn't you be sailing a wooden monohull, or at least an AWB?

Progress.

[LeeV]

Originally Posted by thinwater

If that were actually true, wouldn't you be sailing a wooden monohull, or at least an AWB?

Progress.

No; if I'd been sailing a wooden mono it would've sunk and we might be dead.

[Vets sailing]

Roland. I tied up a couple Purcell prusiks for my tethers out of 7 mil climbing line. Work great. Adjustable, shock absorbing and inexpensive. Use Kong carabiners.

[saishyamnilgiri]

Webbing may be much easier to cut through in case of an emergency. Also they will be much easier to inspect for chaff, wear and tear, general damage compared to round climbing rope.

[saishyamnilgiri]

Also they will be much easier to inspect for chaff, wear and tear, general damage compared to round climbing rope.

[Benz]

Originally Posted by gilligansail

Why are safety tethers made from webbing ?
I've been a rock climber for years. I could easily put together a section of line with an auto-locking carabiner and a snapshackle. What makes the commercial safety tethers worth over hundred dollars?

Gilligan,

With your climbing experience, you should know that there are many perfectly safe ways to do the same thing. If you're comfortable with a homemade rig, use that. Commercial tethers are available because 1) people don't have the experience and confidence to make their own kit, and 2) there is a market for them because of reason #1. I use a daisy chain (you'll know what that is) and a swami belt, and several wiregate 'biners. Clip in short, and you'll never have to worry about shockloads. Have a ton of clip-in spots. If it get's really squirrely, use a second daisy, double up your biners and oppose the gates.