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. 

 

 

 

High Lifelines

6-4-20216, rev. 8-8-2024

Standard lifelines are only slightly above the knee; helpful, perhaps, but not reassuring. For example, reaching over the side to add a sheet to a sail clew can be a little unnerving.

While researching jacklines materials I came a cross a lot of references to high lifelines, rigged to the shrouds. I poo-pooed the idea for years, but now that I have actually tried, it, I think I was wrong, at least for this boat. Yes, they are in the way just a bit, but they make going around the side without a jackline that much safer, they make it safer with a long tether, and they make it better when rough or for those with balance problems.

I used a length of old Kevlar genoa sheet (you want something non-stretch). I investigated all manner of fancy shroud attachments, but a clove knot worked best, with a little tape under it to prevent sliding. Attach it to the lifeline in such a way that the tension is carried by the lifeline, not the stanchion (it looks like I tied the forward end to a stanchion, but there is actually an eye for a gate). The aft end is tensioned with a lashing to another gate terminus.

Reaching out feels casual with a lifeline at your waist.That water is only 45F. Falling in under spinnaker, even on a calm day like this, could be life threatening. Note that I am also clipped to a short tether.

The high line makes a good handline that doesn't stress the stanchions.

Dynamic Tethers

 rev. 4-19-2014, rev 8-8-2024

Stitched Splice Warning. Based on limited testing we have found that nylon rope is much different to sew than polyester rope. Because of the extreme elongation prior to break, the stitching at the tail must carry nearly all of the load, while the stitching near the throat carries no load. It is rather like tug-of-war with a bungee cord; only the 2 men nearest the center can do any work.

Because of this difficulty, I strongly suggest all dynamic tethers be knotted rather than sewn. Climbing ropes have very high knot strength and are drop-tested with a figure-8 to attach the mass. A double overhand noose has also been drop tested. 

[Since this article I switched to a webbing retracting Proline tether by Wichard. I don't like the clips quite as well as the  Kong Tangos, but once you get used to them they are very good. The webbing has a bit more stretch than the prior polyester webbing and can pass the ISO drop test, but with a terrible jolt. After 5 years, the elastic is about shot, so the long tether droops dangerously. It has a quick release on the harness end, but I have mixed feeling about something that can release when I don't want it to. This winter I will either buy a new tether or build a new dynamic tether with Kong Tangos on for all three clips (On my F-24 we detatch the rope end as well, rather than leaving the tethers on the jacklines.]

This subject is a little too esoteric--for most sailors--and so magazines aren't much interested.   Fatalities due
to tethers breaking are rare. On the other hand, bruised ribs and back injuries are more common, but wrongly accepted as a part of rough weather sailing. However, if  we simply apply what we know from climbing about falling--lots or real world experience and lots of lab testing--it just doesn't need to be that way. Let's see if I can sweep away a few bits of conventional wisdom that are just plain wrong. Though you may never sail the Sydney/Hobart, capsize your boat and test the limits of  the human body, routine bumps against tethers don't need to hurt either. We can make our sailing experience more comfortable and safer at the same time. My tethers don't hurt.

____________

Dynamic tethers spliced from 8mm ice climbing rope. Knots would serve just as well. 10mm climbing rope works, but it is heavier and a little rolly if you step on it.

I started my investigation into soft tethers and impact forces years ago, but honestly, my boat is not the ideal
test bed; catamarans don't heel, I don't sail in big waves, and I'm not as willing to risk physical trauma as I used to be. I hold on and I don't fall. However, I've let myself slam into tethers intentionally a few times, just for testing, and I'm not happy with the current state of design. My back is too old.

Let's step back for a moment, before we charge forward, and state the limits of our investigation. We're not discussing jackline and energy absorption. I've covered that before and common experience indicates that a jackline will absorb enough energy to safely slow the sailor. I am discussing only the case of a sailor clipped to a rigid point.

While the Screamer/webbing combination is a huge safety improvement over the typical non-elastic tether, it is really engineered for a different purpose; to catch severe impacts in a survivable way for climbers and workers wearing hip or full body harnesses. Sailors, on the other hand, have a chest harness, which is lousy at distributing force. The screamer is just too hard.


A little backyard testing

I do NOT suggest this as you can easily hurt your spine. I've climbed enough to know what I was getting into.

• Anchor one end of the tether to an immovable object, in this case a large tree wrapped with non-stretch line.
• Create several tethers, 6 feet long from test materials: 1-inch nylon webbing,  1-inch webbing with Yates screamer, 10.4 mm dynamic rope (UIAA single), 8.2 mm dynamic rope (UIAA double).
• With increasing amounts of slack in the line, run at the end of the tether as hard as you can back first.

Results:

1-nylon webbing with Screamer. A very tough stop. With about 3 feet of slack I was able to just get the Screamer to trigger and it hurt. My back will complain for a few days.
10.4 mm rope. Firm stop. I didn't go further than 4 feet, not wanting injury. I'm sure I could have run from 6 feet with no harm, though it would be a jolt.
8.2 mm rope. Even at 6 feet and with a sore back, the stop was practically fun. It might take you off your feet, but was no harder than hitting a well padded couch. At 2-3 feet it was only amusing, with about 1-foot of stretch.
1/4-inch Amsteel. I was smart enough not to try. It would be worse than webbing without a Screamer.

General Observation. I wear my harness high, nearly in the armpits and definitely on my lats. If the harness had been worn lower, where catalogs show them or where combo PFDs fit, I would have injured my ribs.  Whiplash is also a problem. Wearing a harness down near the solar plexus and lower ribs, where so many are located, is plainly dangerous.

In the end, only the 8.2 mm rope felt good, thought the 10.4 mm was livable.


Data and Calculation

Is it strong enough? 8.2 mm line is not 5000-pound rated, but as we will see, it is far tougher (can absorb more energy) than 1-inch webbing.

What do we know from laboratory and real-world fall data? For new products....

• Webbing tethers are just adequate: They occasionally fail at forces near 4000 pounds. Rare, but we can use that as a design point. 
• 1-inch webbing can just manage a 6-foot fall with a 185-pound rigid mass; this is generally considered as equivalent to a 200-pound person, since the harness and body absorb some energy by deforming (data from DMM, a climbing equipment manufacturer).
• 10.4 mm UIAA single rope can manage more than 10 falls from nearly twice this distance.
• 8.2 mm UIAA double rope can manage more than 10 falls from nearly twice this distance with a 242 pound rigid mass (261-pound person) using 2 strands.
• 8.2 mm UIAA double rope can manage more than 10 falls from 6 feet with a 242 pound rigid mass (261-pound person) using 1 strand. Thus, it is more than 50% tougher than 1-inch webbing.
• 8.2 mm UIAA double rope can manage one fall from nearly twice this distance feet with a 242 pound rigid mass (261-pound person) using 1 strand. Again, it is more than 50% tougher than 1-inch webbing.
• 1/4-inch Amsteel is the worst material that could be used. While strong, its energy absorption capability is negligible. Its only advantage over chain or cable is light weight.

I created data using well-used products. Why used? Because they will become so, obviously. Less documentable and less repeatable by others--science is all about reproducible results, be they real-world or not--but ultimately more practical.
 

 Percent Elongation (left) vs. Pounds Stress, pounds (bottom)

Webbing is 3-5 times stiffer than dynamic rope. Amsteel is very stiff.

I took the samples and pull tested them up to 2500 pounds; I didn't feel like destroying my tether just yet. I used on-line data  to extrapolate out to the breaking point of each material. In dynamic situation, the breaking strength and the elongation to break is typically 30% less and energy absorption about 3 times less, but for blog post purposes, the above data at least allows comparison on an equal basis.

What matters is the area under the curve.

Static Energy Absorption, 6-foot tether, ft-pounds (left) vs. Stress, pounds (bottom) 

Static calculated energy values are greater than fall values for 3 reasons:

• Ropes are tested with figure-8 knot, weakening rope by ~ 40%.
• Dynamic testing does not allow for heat dissipation and reorientation of fibers.
• Dynamic ropes survive 8-12 falls, the webbing only 1 fall in our test data. Dyneema survived zero test falls.

Dynamic Energy Absorption, 6-tether, ft-pounds (left) vs. Stress, pounds (bottom) 

 At lower stress, 8.2 mm rope absorbs more energy for a given impact force, but eventually 10.4 mm rope has greater capacity. Both dynamic ropes have greater energy storage capacity than webbing. 8.2 mm rope is more than twice as tough as 1-inch webbing.

Both this data and UIAA drop data thus confirm the following:

• 11mm rope can absorb many fall factor 2 drops.
• 8.2 mm rope can absorb 1 fall factor 2 drop.
• 1" webbing can absorb 1 fall factor 1 drop.

What happens in a 6-foot test fall?

• 1-inch webbing: At 4000 pounds impact, 1100 ft-pounds energy. We know from fall testing, however, that 1-inch webbing can only absorb about 1100 ft-pounds (sometimes passes, sometimes fails), so we will use 1100 ft-pounds as the design point.
• 10.4 mm rope:  If we accept the design point only 1100 ft-pounds of energy, impact force is about 1400 pounds. New rope fall data indicated significantly less.
• 8.2 mm rope: If we accept the design point only 1100 ft-pounds of energy, impact force is about 1100 pounds. New rope fall data indicated significantly less.
• 1/4-inch Amsteel: Only 236 ft-pounds of energy were absorbed by the point 5000 pounds of stress were reached, and only 677 ft-pounds of energy were absorbed at the break strength of 8600 pounds. Amsteel will kill the sailor and pull the harness apart before surviving a 6-foot fall. This has been duplicated in real-world fall testing with spectra products; Dyneema is worse.

If we limit the fall to something more reasonable--a 2-foot fall is similar to wave strike and 6 knot stumble, and more severe than my backyard testing--the energy for me is only165# x 2' = 330 ft-pounds, which can be absorbed by a 500-pound impact; you'll feel it but not get bruises. With a webbing lanyard it would be 3 times that pressure and you will be injured. A Screamer will trigger but not be fully spent (though they are single-use).

How much energy can a Screamer absorb? About 270 foot-pounds according to several testing sources, or about 25% of a 6-foot fall; in combination with the stretch of the webbing, enough to reduce the impact force below 2000 pounds. And then you bottom out and the force goes up, though less so.

Other Factors. Does the extra stretch bother you? Probably personal. Is stepping on rope a greater hazard than webbing? For 8.2 mm rope, not much, but on a monohull (sloping decks) that may be more of an issue. Construction? Either knots (testing assumed figure-8 knots) or sewn eyes are practical.

A critical biometric factor, not easily relayed by a machine or simple data, is that a force that comes on gradually (the dynamic rope) allows the muscles time to tighten and resist. A sudden 500-pound kick before a screamer gives is painful and damaging, like a blindside blow, even at the same force level. You truly feel the difference. 

Dynamic rope or a screamer--The best solution? For smaller, more routine falls on the deck, the rope is
kinder. For that once in 100 sailors' lifetimes, torn from the cockpit by a rogue wave impact, the screamer/webbing combination is competitive, though the climbing rope tethers are still survivable without serious harness impact injury; both could have impact forces of 1000-1500 pounds depending on the force of the wave, and it would hurt, but not break ribs or vertebrate. A climbing rope, even 8.2 mm, has greater energy absorption capacity than a webbing/Screamer combination. Thus few climbers use Screamers, but they ALL use dynamic ropes.

The only disadvantage of rope over webbing is the  potential for rolling under foot. A dynamic webbing would be nice, but I could not find any. On a catamaran this is a limited problem (level decks), and the roll-under-foot potential is reduced by the small size of 8.2 mm line (5/16-inch).

What have I done? I've switched to 8.2 mm dynamic tethers. It is kinder on the back for minor falls and even over the edge. It is lighter than the webbing/Screamer combination and easier to hold on to.

-----------

Where to get limited quantities of dynamic (climbing) rope?
MEC sells both single and half rope off spools, by the foot.
Half Rope,
Single Rope.

Small Boat Jacklines

Conventional jacklines down the sides make sense on larger boats. They can be far enough inboard for safety and still allow mobility. The bow and stern are still problem areas, but stopping them ~ 5 feet short of the ends solves that. You can clip the bow rail with the 3' when working there, leaving the 6' tether on the jackline.

Smaller boats require a different aproach. 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. 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 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. You are never unclipped. You also never move from 6' radius to 6' radius hard point, which requires unclipping.

May 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.

MacGregor 26D
Red lines are jackline range of movement
Blue lines are are point range of movement

Cruising Small, Cruising Fast

A New addition to the Bookstore

I started started sailing on a beach catamaran. I heartily recommend learning on a small boat, because they teach a sense of the wind and waves that is hard to gain on larger boats. But if you want to go farther or spend the night, you really need something with a bunk. But you don't need 50 feet of shiny fiberglass and the mortgage and slip fees that go with it. That's what they sell in the mags because that's where the (your) money is.

And to be honest, big boats aren't that much fun to sail, not after you get the hang of it. They're more about learning the systems and planning than actually sailing. Would you you rather go for a bike ride or drive a Winnebago around town? Personally, I'd take the bike, and that is why I downsized from a cruising cat to a 24-foot trimaran; the smaller boat sails better and I feel the wind again. I missed that on the cruising cat.

The thought that brought fire to my pen is that too many sailors feel that sporty boats are for racing. Poppycock. They are for whatever is fun, and if you only take the plunge, you'll see that fast cruising is a blast, though it can be a bit more like camping that staying in a hotel. Of course you can do both; sail fast from point A to point B, and then stay in a motel.

And that is the sort of thinking that goes into cruising fast and small. Ignore the magazines and make it work. You've never had so much fun!

A Locking Carabiner... That Isn't

This the SECOND warning regarding Gibb-style hooks. The first warning related to with low side force strength.

I mentioned earlier that I had been testing carabiners as a result of the Clipper Race fatality. There is a long article in Practical Sailor that describes, among other things, how certain carabiners can fail as low as 275 pounds if loaded from the side or clipped improperly. It gets worse.

You know how ISAF and ISO rules require locking carabiners because non-locking carabiners can twist off?

This was done with one hand, while the other held the camera. No special test gear.

The Spinlock Race Clip. The Plastimo Gibb hook behaves exactly the same way.

It seems that the original Gibb patented hook has been modified over the years. No only is it weaker, it does not really lock.

And this isn't just about u-bolts. In this video we show what happens if the carabiner is on a jackline and is pressed against a cleat or similar object.

Did this contribute to the Clipper accident? In fact, I think it may be the primary mechanism. The carabiner was clipped to a jackline that ran beside a cleat. When forced to the side against the cleat, the gate opened and the carabiner hooked the webbing. The resultant nose-hooked condition is very weak (failure starts at 275 pounds) and it soon failed.

Notice the white jackline on the deck behind the mid-bow cleat. I believe the clip was pressed against the cleat and opened, resulting in a nosehooked condition, which is very weak (~ 300 pounds). This results in a carabiner tnat EXACTLY matches the failed hook. 

 This shows a progression from 500 pounds through 1200 pounds, matching the final hook condition (Clipper hook, top).

So the Gibb-stle carabiners have not one, but FOUR fatal weaknesses:

•  Gate can be forced open at 10-15% of EN climbing carabiner standard (20-30 pounds vs 225 pounds)
• Nose hook strength is 15-30% of typical (as low as 275 pounds).
• Side load strength is 10-20% of typical (as low as 275 pounds)
• Nose is prone to hooking. Should be key lock style.

I'd retire them if I was you. Obsolete and scary.In my opinion, the companies involved should issue a recall and are opening themselves up if they do not.

Tether Testing

A big article will be coming out in Practical Sailor next month, in the wake of the Clipper accident involving the failure of a Spinlock race hook at only 300 pounds. The clip was apparently caught in an odd bind, perhaps under a cleat, and it just wasn't made for that.

From top left to bottom right: Wichard snap shackle, Wichard Proclip, another Proclip, ISC SH 903, Kong Tango, and one last Proclip. These are 8-10 times stronger than the stamped Gibb-style safety hooks.


And yet there have been products on the market for decades that are stronger, as much as 10 times stronger  when levered over an edge.

I've been using the Kong Tango. It's fast strong, and durable if you clean and grease once in a while. The Proclip has a lot going for it; very hard to release accidentally and nearly corrosion-proof. The ISC SH 903 requires two separate unlocking actions before the gate can move; about the only thing more secure is a moused screw pin shackle. All of these open wide enough to clip a 1-inch railing and are workable with gloves. That's why I'm out testing them in January and February. Read Practical Sailor for the details.

All great products.

---

How do you keep the tethers out from underfoot when you aren't using them? Around the waist like a belt, naturally. I picked that up from a Volvo race guy.

You can spy it just under my elbow, completely out of the way.

Chest Harnesses--Is a Wider Belt Better?

rev. 8-9-2024

In the earliest days of rock climbing, a chest harness, not to different from sailing harnesses, was the thing. Actually, before about 1960, that harness would be made of rope, and hanging in it for more than a few minutes often resulted in permanent injury. Suffocation and broken ribs were also common, so the climber was careful not to fall. By the mid-1980, seat harness, much like those in use today had become standard , and climbers frlt much more free to take the occasion fall (ropes had improved a lot too). But in the time in between, from the 70s through early 80s, a waste tie-in was most common in the US. This is when I started climbing.

3- and 4-inch swami belts from about 1980.  I used the top one regularly for about 7 years.

At first it was just a rope, but soon a bowline on a coil became common, which is much more comfortable. about 6-8 wraps of line were taken around the waste and cinched off with a modified bowline tied around the coil. It wasn't that comfortable, it consumed about 25 feet of rope (pretty significant if both climbers did this), and was time consuming to get on and off the rope.

 

Climbers started wrapping webbing into a wide belt, but the width was hard to control and after shifting or falling, was often no wider than the webbing. Soon, climbing shops started producing fleece-lined swami belts 3-4 inches wide with accessory loops. You lashed this around your waist with 1-inch nylon webbing. It was more comfortable, and so long as you were young and had strong core muscles, tolerable in gentle falls and hanging for short periods. Better than a chest harness, anyway, although that seems improbable. I swear, based on many experiences, it is true.

Interestingly, they never got wider than 4 inches. It didn't seem to help must and got combersome. Soon after these were developed, shops started making leg loops to go with them, and thus the modern seat harness was born.

I tape large stiff foam pads inside the leg loops of my harness if I'm going up the mast for a long while. It really helps.

The ISO standard for sailing harness in 45 mm (1.75 inches), and most are this width. This is also the standard for rock climbing harness and automotive seat belts. However, most rock climbing harnesses have leg loops 2 inches wide and 3-inch belts. Racing seat belts are 3 inches, with 6 belts instead of 2.

While a full body harness is what you really need to take a huge fall, that's just not practical. But could a chest harness be improved by making the band wider? A very simple thing to do.

I should have started from scratch, but I'm down to a writer's meager income, so I reworked an old harness I had. Though it has some rust stains, it hasn't been in the sun much the webbing is far stronger than the code requires. By removing some hardware, resewing a few things, and adding a fleece lining (why not--it will feel good in the summer), I increased the width from 45mm to 70 mm, or 56% more area. Yup, it feels better when hanging, though it is still horrible, like any chest harness.

Stiffer webbing would help. No, it is not adjustable; it's just for me and I have another for winter wear. Loosing the buckles makes it lighter and more comfortable.

rev. 9-8-2024 I made this one just for me and have been using it for 6 years. It's non-adjustable, which makes it lighter. I have one for winter and one for summer. A Fastex buckle closes it but the tether clip goes through both rings. Very light, comfortable against the skin, nice and wide.

I will be testing 45 mm, 3-inch, and 4-inch straps for an up-coming article. However, I know there is a limit. Even being hoisted with a well padded LifeSling really stings after a few minutes, so don't expect miracles. But if it saves a few bruises or a broken rib, it's a big deal. I'm thinking 4 inches would be a sensible standard, but let's see what the tests say. As near as I can tell, the design of the straps and buckles makes no difference under load, only the width of the strap.

Update 9-8-2024. Yes, I did the testing. It's all about the strap width. Less than 2 inches is asking for a broken rib and 3-4 inches is much better. But nobody makes them wide. I guess they don't actually use them.

The Clipper Round-the-World Race and the Failed Tether

Some of you are likely aware of the Clipper Race, where amateur sailors ranging from considerably experienced to land lubber pay for a slot on a race boat. There are two paid crew for 18 guests, so hand holding is limited. This is quite different from either the pure amateur or pure professional models, where the crew must earn a place on the boat.

During the last race, a 60-year old retired lawyer fell off the bow and drowned. He was tethered, but the carabiner on the tether failed. Forensic testing of identical clips confirm that because of the way the tether was pulled, instead of failing at over 4000 pounds as expected, it failed at about 300 pounds, a force easily generated in a modest stumble.

That is a staggeringly low failure strength. How could that happen? Unfortunately, if I told the full story, my editor would choke me, so I will just have to refer you to Practical Sailor. We've been deeply involved in investigation. There is an interesting post on Facebook right now (link below) and the full story will be out in a few weeks.

Practical Sailor Clipper Up-Date, Facebook

I will share this, however. My tethers don't look like that. I have a few spare hooks left over from testing but they won't be going on the boat. In fact, if you showed any rock climber this sharp-edged monstrosity and asked him to trust his life to it, he would tell you to get stuffed and pitch it deep in the woods. Honestly, it looks like a toy carabiner to me. The metal is too thin, the edges are sharp enough to cut rope and even steel climbing slings, the internal lock can jam on rope and webbing, and the nose snags everything in sight.

I use something a bit different. The carabiners are from rock climbing and via ferrata. They are better proven, more thoroughly tested, and subject to a tougher standard. The lanyard is 8 mm climbing rope and absorbs impact, keep the force on my chest comfortably low. I'm hoping the standards for marine tethers and carabiners can be changed to be more like these.

I'm thinking that the sailor might still be here. But make no mistake, off-shore sailing is dangerous, and if you fall over the rail, the ocean can beat you to death in short order. Keep your tethers short.

When to Splice

There's a lot of snobbery surrounding splices and knots, as though knots are only used by hacks that can't splice. The thing is, I know perfectly well how to splice most materials--I've published several articles on testing of splices and knots--but I only splice when it is the logical answer. In fact, I find it embarrassing to have splices where a knot is the better choice.

It comes down to four differences:

1. knots are easier to redo
2. splices are stronger
3. splices are lower profile but longer
4. knots are more abrasion resistant in double braid

The Marlow Splicing Fid is my long-time favorite for 3-strand. You push it through to open a spot, insert the strand, no matter how frayed, and it pulls it back through. Very fast.

When to Splice.

High Strength

• Docklines
• Snubbers
• Rope to Chain (no other method will pass through the windlass)
• Safety Tethers 
• Jacklines

Won't Hold a Knot. This means Dyneema/Spectra in most cases. Fortunately, a bury splice is dead simple and a brummel not much more difficult.

No Room. Rubbing with tackle. Sometimes a knot will get in the way, though often this can be avoided by trying a different knot or rotating it 180 degrees.

Snagging. Splices are generally smoother to run, though flipping a knot over can help.

• Genoa Sheets
• Safety Tethers. 

Can't be Constructed Any Other Way

• Soft Shackles
• Adjustable Stropes

Adjustable strope. From "Keeping a Cruising Boat on Peanuts."

The Brian Toss Wand is my favorite for double braid. I use a cut-off hollow knitting needle for single braid.

When Not to Splice

Must be Re-Made at Some Frequency.

• Halyards. First, I like to cut a few inches off every few years to move any chafe spots. Second, halyards are sized for stretch, not strength, and as a result are massively over strength. 
• Most tackles. Should they twist-up or a component fail, knots are easier to re-do.

Splice Will Jam. A splice makes the rope fatter. Sometimes this causes a jam in a block. It also keeps tackles farther apart than a knot.

• Halyards
• Traveler
• Davit tackles 

Abrasion. A double braid splice caries nearly all of the load on the cover on one side, and it is vulnerable near the throat. A knot breaks inside and is thus generally unaffected by wear and UV.


Old Double Braid

Even if a splice would be nice, old double braid rope is impossible to splice, IMHO. The solution is either a knot (obvious) or a sewn splice. These can be just as strong as a conventional splice, although they do required protection from UV and chafe. When don properly, they'll last as long as the rope. Much industrial
splicing is sewn.

My genoa sheets, made from a salvaged big boat halyard.  The cover is 2-inch tubular webbing. This splice is 5 years old. From "Keeping a Cruising Boat on Peanuts."

Dynamic Rope

The tight cover makes a splice nearly impossible. Additionally because it is dependent on both the core and the cover the splice is complex.  Most industrial tethers are sewn.

This is my deck tether. 8 mm ice climbing rope.

a. Yes, those are screw lock carabiners. I keep them well-greased, and because of the boat design, they generally stay on the jacklines.
b. The rope is sewn. Do NOT try this unless you have done a lot of sewn joint testing.
c. One leg is 2', the other 10'. This is for a cat with narrow side decks and a wide fore deck. On my try I use conventional tethers. 

But note that I have a storage spot for the spare tether.

Never Remove the Lifelines

And what about the insensitive _____ that's filming it all. The guy is actually in real trouble.

High Lifelines

Standard lifelines are only slightly above the knee; helpful if sliding, but not reassuring while walking. For example, reaching over the side to add a sheet to a sail clew can be a little unnerving.

While researching jacklines materials I came a cross a lot of references to high lifelines, rigged to the shrouds. I poo-pooed the idea for years, but now that I have actually tried, it, I think I was wrong, at least for this boat. Yes, they are in the way just a bit, but they make going around the side without a jackline that much safer, they make it safer with a long tether, and they make it better when rough or for those with balance problems.

I used a length of old Kevlar genoa sheet (you want something non-stretch). I investigated all manner of fancy shroud attachments, but a clove hitch worked best, with a little tape under it to prevent sliding down.

• Attach the high lifeline in such a way that the tension is carried by the lifeline, not the stanchion. It looks like I tied the forward end to a stanchion, but it is actually secured to an eye in the lifeline for a forward gate. The aft end is tensioned with a lashing to another gate terminus.
• Use very low stretch line, either Kevlar or Dyneema. However, bare Dyneema would be very difficult to secure to the shroud; it would need to be covered with polyester jacket that that point. In truth, the larger diameter line makes a better hand hold.
• Unlike conventional lifelines, there is no taboo against leaning on it. The horizontal force is carried by the shroud.

Reaching out feels casual with a lifeline at your waist.That water is only 45F. Falling in under spinnaker, even on a calm day like this, could be life threatening. Note that I am also clipped to a short tether.

The high line makes a good handline that doesn't stress the stanchions.

I've been using these for two years by now and I am hooked. Though I still use a tether if it is rough (and for these pictures), in actual fact the new line frees me from the tether on most days, since the bow and stern of a catamaran are very broad and safe in moderate conditions.

A Rant About Jacklines and Tethers

rev. 7-24-2024

Windward vs. Centerline

The old conventional wisdom was windward and leeward lines, in as far as the cabin and shrouds would allow. Now the new mantra is centerline, and that anything else is unsafe and the user uninformed. They blithely ignore facts suggest something different:

• You can't slide uphill.
• Every case of injury by dragging along side was to leeward. They were caught in the bow wave.
• It is farther to leeward if the jackline is to windward.
• Waves and gusts come from windward.

The new internet forum wisdom feels more like group think than change based in evidence and experience. By all means move the jacklines in as far as practical, but I believe the physics of falling limit windward overboard incidents. If you know of a documented case, please comment.

[note: The Cal June Jim Buoy model 9225 harness that I am wearing does not pass ISAF or ISO standards and I am not recommending it.It is lightweight, comfortable, and I believe that it is adequate with the shock absorbing tethers that I use. The failures occurred at forces 3 to 4 times greater than my engineering design allows.]

 

7-24-2024. I have long since replaced this with a better harness, but still home-made (I have experience fabricating rock climbing gear--don't try this at home.  The reasons I fabricated my own are:

• Wider chest band. Testing suggested that anything less than 3 inches is asking for a rib injury.
• Fleece lining.Much more comfortable if wearing a thin shirt or no shirt.
• Easier on-off. The new harness closes with a non-load bearing 1.5 inch Fastex buckle. The closure is maintained in use by the tether clip. 
• Non-adjustable for lightweight and simplicity. One for summer, one for winter, to allow for layers.
  

Watch in Practical Sailor for an article on jackline locations.

 For me, windward lines and short tethers are the best bet. And my boat doesn't even lean!
 

Quick Release vs. Locking Carabiner at Chest End of Tether

As a single hander, I'm fairly certain that cutting myself free is seldom better.

• Cold water. Today, for example, I was sailing on the Chesapeake with 34F water temperatures. I did not see a single boat over a 4 hour period. Unless we all take to wearing drysuits, the only ending is slowly freezing in your PFD. 
• Accidental opening. Ever have a spinnaker shackle release unexpectedly? Granted, it was generally because the shackle was not closed properly, but that is only proof accidents happen. A locking biner is more secure.
• Offshore. Same as cold water. Yeah, someone could be coming for you. Probably not. 

I don't fancy the idea of dragging, so I keep my tether short when near the rail, and crawl when I need to.

Not a screw-lock on the tether end (Kong Tango). That would be silly. 

rev. 7-24-2024. I now have tethers with snap shackles on the harness end and tethers with a Kong Tango. I feel like the snap shackle makes sense in-shore and if the water is warm or I am wearing a dry suit. Swimming is better than dragging.  But I still feel it is situation specific and that US Sailing is wrong (require snap shackles) and World Sailing is right (leaves the choice to the user). For example, if I were single handing across and ocean , I still don't see how releasing is going to be much better, and I still feel that accidental release is the greater risk.

 

 

As for multihulls, just keep the jacklines well in the from the edge. You've got lots of room. Also, because multihulls can stuff and stop fast, terminated the jacklines 4-5 feet back from the front edge of the tramp.

Jacklines--A Centerline Aproach for Monohulls

Where to run the lines is always controversial. Along the side deck is traditional, but that leads the sailor right along the precipice, troublesome on the windward side and scary on the leeward side.  I run mine over the hard top and on the edge of the cabin. These sailors take it further, running the lines near the center. Yup, you are forced to re-clip near the mast, but the result is good protection on a narrow bow.

I'm not sure it's for me, though. I don't think people actually fall off to windward.

Jackline "Frost", an Amel Maramu

Jacklines, Tethers, and Why Monohulls and Catamarans are Different

Often I post just to help order my thoughts. Some comments are posted and some come by e-mail and are not posted. They all help.

I've posted on tethers many times, always with caveat that my views were catamaran-specific. Now I have begun with actual drop testing, with an eye towards a published article, and solutions must be more universal. Or at least we need solutions for all boats and all uses.

A few of my notes. Scary if you can read them.

The crux is figuring out where sailors actually fall.

The bow, catamaran. On a cat the bow is wide and you should be on the windward jackline, even if it is long. If very rough and I need to lean out to add something to a clew, I've been known to clip both the leeward jackline with the short tether and something else with the windward line (the windward line will not allow me to lean out). If you do happen to go over, there is no bow wave trying to suck you under and drown you; the hulls are too fine for that. Upwind, waves can come over and wash you around, but a tight line to the weather jackline manages that, and falling on a tramp doesn't hurt. Getting thrown forward is the greater risk, as the boat stuffs a wave and slows suddenly; the cure is to terminate the jacklines some distance aft of the bow, just as they terminate forward of the transom. A clipping point in the center of the tramp is often handy, as many cats lack a forward lifeline, and on many boats the lacings are strong enough and serve very well. Lacking that, adding several strong sewn points 3-5 feet aft of the forestay can be logical and simple. Because the tethers are long, stretch is needed to reduce impacts, but only when clipped to a hard point; jacklines provide cushion. Falling off the weather side is managed by running the jacklines well inboard--we've got wide decks.

Getting lifted off the deck is also a problem. Catamarans commonly experience negative Gs up front, and the best answer is to have a jackline you can pull up against, keeping the feet on the deck. Again, the jackline should be well inboard, since the lift can throw you to windward or leeward. Again, a hard point on the tramp near the forestay is handy; when kneeling near the forestay it is common to float upwards.  For the longer tether leg, shock absorption is nice; I've been thrown 12 feet before, airborne from the cabin roof, landing on the tramp. Between the give of the tramp, tether, and jacklines, not a bruise.

 Clip toe rails from underneath--clipping from above can torque the carabiner.

Catamaran, aft. The risk here is simply falling off the back, and stumbling cause by a cat's quick motion. Since the tether is clipped to a hard point, there is no shock absorption, and the tethers are long. Getting swept by away by a wave is a minor risk on most cats; forward, yes, but not in the cockpit, not ever. The boats move over and away from waves. However, tethers are needed when working outside and aft.

 Look at the corrosion in the stanchion socket.

Monohull, bow. The scary fall is to leeward, under the bow wave. Folks have drown there. And thus, a quick release is required, something of much less interest to a cat sailor. The answer there is a short working tether to a fixed point to weather, and a secure grip. It gets skinny up there, something cat sailors don't face.

Monohull, aft. All documented tether failures have been in the cockpit. The helmsman was stuck by a wave, thrown the width of the cockpit, and lacking any shock absorption (clipped to hard point by a static tether), overloaded the system. Broken ribs and other injuries due to tether impact forces were involved. There are 2 answers to this problem: clip short and use a dynamic tether.

Short, working tethers are important, particularly for boats racing in extreme conditions. Very few falls are documented while people are moving; they are holding on. It is when they get to the work station, take their hands off the rails and focus on the task, that they get thrown. Thus, there should be a good anchor for every station, located such that the sailor cannot get thrown. On boats prone to stuffing the bow--some cats and some sport boats--a tether from behind may be prudent.The new AC cup boats have a tether requirement, specifically directed at stuffing a bow when bearing off. Keeping sailors on-station can prevent a capsize, since they can still do their job. The personal tether must have a short leg, or a fixed tether can be provided at each station.

Dynamic tethers are another part of the answer. ISO standards now required a drop test that should create nearly unbreakable tethers, but they may break the sailor in the process (unlike climbing drop tests, they did not specify a maximum impact force). I'm still using 8mm dynamic rope tethers, which are considerable lower in impact and tougher (can absorb more impact) than ISO  tethers, but they have one drawback; the rope can roll under foot. I would love to find a webbing with required stretch properties, but I'm not certain it exists; the weave may prevent that.

----

There are other issues.

• The best quick release.
• The quick releases must be accessible when the PFD is inflated (most are not).
• Harness design. The ergonomics are terrible, but there is no practical test method, and short of a full body harness, no good way to transfer the load to a body without damage.
• Where you you park the spare tether leg clip when not in use? Don't clip it to your harness, or you will have no release. But most tethers provide no alternative. My advice is to add something.
• Folks don't like tethers, particularly if there is crew on board.  But is the crew skilled enough to get the chute down and get back to you? Hmmm.

---------

So what are your MOB concerns? Where can you take a hard fall on your boat? What have you witnessed or read of? We need data to design solutions. 

Is Your Tether Quick Release Actually Quick Release?

rev. 7-23-2024

This tether was found by rescue workers at the Wing Nuts accident site; there were several fatalities.

Where do you clip the "spare" leg of a 2-leg tether? To the harness ring, or course, if there is no loop on the tether... and there is not. Pull the quick release and you are still attached by the spare leg. A potentially fatal design error.

This is dangerous even on deck--if the tether gets wrapped around a sheet or guy he has 2 clips to release to get free. Not good.

And this points a scary trend, where equipment companies design to standards but don't actually test the gear in the field. They give the gear to sailors to use, but that is hardly the same as structured testing where all likely use scenarios are systematically tested.

The solution? some brands are adding a ring or loop near the harness end. If you make your own, leaving the loop long enough will do. Or in my case, I simply clipped in a small biner to give myself a parking space.

The typical vendor response? "You should have a knife." Really? Many of us do carry a knife, but that's just one more thing to dig for while you're fighting for your life. You'll probably drop it. Why not just say "I shouldn't fall off the boat?"

Via Ferrata Tethers--Some Good Ideas, But Not for Sailing

Via ferrata trails, literally iron ways in Italian, are climbing trails equipped with rungs and safety wires that allow fit but unskilled personnel to move quickly and safely over difficult terrain. Though they date back into the 19th century, they are best know from their use during World War I, moving troops through the mountains.  Since then they have expanded to thousands of tourist routes in Europe and the United States. Since tether technology is the focus of this post, I'll leave history research to the reader; the internet is great for that.

The climber is protected falling all the way by a pair of tethers that follow a safety wire to the side of the rungs. Periodically, the wire is fixed to the face, and this is the challenge; these points are generally  10-20 feet apart, allowing for  serious falls before the tether takes, and requiring the tether to absorb a great amount of energy, more than a dynamic rope alone can handle. Dynamic ropes are rated for a fall factor of 1.8, whereas a via ferrata fall can be fall factor 5 or more.

The solution is a more extensive energy absorption system, including either friction through an aluminum plate or a tear-type energy absorber, like a Screamer.

Why wouldn't these make useful sailing tethers?

• The allowable impact force is much greater, since the load is taken on a seat harness rather than a chest harness; the human tail can take a lot more force than the ribs. Sailors need a softer catch.
• The falls are really much greater. A sailor will never see an impact beyond fall factor 1; the ISO drop testing required by the ISAF rules is based on a FF1 with a 100Kg mass.
• The end clips on via ferrata tethers are applicable and gaining popularity. The West Marine tethers are now Kong Tango via ferrata biners (pictured on tethers to right), and I like them very much. Fast on and off, one-handed even when cold and wet, locking, light, and fit over most handrails too. Because they are aluminum, they do require periodic lube and rinse. Mine have held up very well, like new after 2 seasons.
• Harness attachment. Sailors like a quick release on the tether, something that can be removed under load. Climbers opt for a locking biner, since no possibility of accidental release is acceptable. Most often the tether is cow-hitched to the harness.
• Length. Sailors like dual lengths (2-3 feet and 4-8 feet) while climbers are restricted to 2 matching arm's length tethers; they never want the clip to move out of reach (if it snags below you this is a real drag).

Certainly there are some ideas here, some worth adapting, but the application is different.

-------

Note on recalls. Because of the extreme nature of the falls and untrained nature of many users, there is some history of failures, most often fatal. In general, the causes have been:

• Fall too great. Anything of 10 feet is trouble and over 15 feet is beyond the equipment rating. The via  ferrata trails generally recognize this, placing tie points ever 10-15 feet, but risk is often part of  climbing; if it looks too scary, go down.
• Worn friction rope. Some designs rely on a rope slipping through a plate with many holes. If the rope wears through use--tour groups use them daily--the rope slides more easily and insufficient energy is absorbed. This type has gone out of production because they are too difficult to inspect.
• Poor or worn stitching, or any other construction fault, though this type of failure can result from too long a fall.

ALL via ferrata falls are bad, far more dangerous than falls on a climbing rope. They feel safer but are not. The impact forces are high and there is much to hit on the way down.

Relocating Jacklines

Formerly the jack lines terminated at the forward beam; simple and strong, but cause a tripping hazard. After far to long a wait, after a suggestion by my daughter, we relocated them to the edge of the tram, where combined with a small back-up plate and the natural strength of the hull flange and trampoline track, there is a natural strong point.

The aft end is still anchored to the hard top railings, the spliced end of the dockline cow-hitched around a center point attachment, spreading the load.

The forward end is lashed (many passes of polyester cord adding up to a 5500-pound line, with padding under for chafe) to a 316 SS bolt hanger. The chafe gear is for UV protection.

Less of a trip problem, equal access, easy to re-tension.

--------------

Why rope instead of webbing, as is the conventional wisdom? Though I've discussed this before...

• UV. We leave them rigged 365 because we believe night comes every day, the water is cold in the winter, single-handers need to stay on the boat, and thunderstorms give little warning.
• Under foot? We don't worry about stepping on them because they do not run on the deck.
• Stretch. We like the stretch of nylon dock line because we have a cat and used long tethers. If we were a mono-hull we would use something lower (but not zero) stretch.

And we use 2-arm tethers. One about 84" and the other about 30". Fit them to YOUR boat.

The Need for Everyday Jacklines

It was a little breezy today--sustained at 20 knots with gusts to 30 knots. The water and air were cool, both perhaps 45F. A beautiful day for some brisk solo sailing.

I started out with full sail, but within 15 minutes a reef seemed smart. 30 minutes later a second reef seemed smart, along with a little jib rolled in as well. No worries; even though I reef at the mast, the jack lines are always rigged and the auto helm was holding course nicely. Just a time to be causious. The bow was going through as many waves as over them and the motion was a bit crazy, but that's what fall sailing is about.

I noticed I had left the boat hook bouncing around on the deck; I never tie it down and it has bounced there for over 2000 miles. But it was getting washed around more than normal. It had been tossed from the tramp up on to the seats in front of the salon. Its bent, but its a friend. But I have a spare on board, found on along beach somewhere.

I noticed the spinnaker bridle had somehow worked loose--last time it was used a guest secured it, or rather didn't--and there was some question in my mind as to whether it could get under the boat and into the prop or rudders later. I figured I needed to go get it. Except that 45F water is washing ankle-deep across the tramp every 10 seconds, everything is soaked with sheets of spray, right up to the dodger, the tramp is a wide expanse free of handholds, and I was sailing alone. Bugger.

And this is why you keep jacklines rigged EVERY DAY. No problem, I clipped in, walked along the side, used the jackline in one hand to ease my way across to the leeward side, and clipped in with the short leg. After securing the lines and grabbing the wayward boat hook I hauled myself to windward with the tether and retreated to the cockpit.

I tacked and broad reached home, faster, with less motion... and no concerns.

Bolt Hangers--A Strong Point For Small Dollars

Cheap hardware via cross pollination from the rock climbing world. In the mountains these are used in combination with wedge bolts to create strong anchor points. On a boat...

• 5,000-pound strength anywhere a single 3/8-inch bolt is handy. Of course, a good backing is required.
• 316 stainless steel.
• Cheap. About $3.95. (others brands may be 304 or other grades, some of which have been known to fail in marine environments.)
• Designed for clipping carabiners, they easily accommodate 2 carabiners.  
• Obvious purpose avoids confusion over acceptable strong points. Strength rating and certifications are stamped on hanger.

Countless potential uses. A few of mine....

• Add an extra block to a sail track.
• Add an anchor point at the stern for diverting mooring lines or attaching a dingy.
• Tether and jackline anchors. Don't tie rope or webbing directly; the radius is too short for acceptable strength.
• Anchors to secure bicycles.