Climbing Gear for Sailors--Jacklines and Harnesses for the Unemployed

 rev 3-25-2012, rev. 4-6-2024

 
Yes, I am cheap. As much as I would love to lavish buckets of money on my sailing habit, there are 401-Ks, college funds, boat payments.... More to the point, I hate throwing money at West Marine or Lay Line for things that are not so well engineered and for things that are not inherently "marine" in nature. Climbing gear is an example: sailors know sailing, climbers know falling.

Example: a few years ago special rope-handling gloves for climbers became the rage. All sorts of designs came out, none as good as sailing gloves. Eventually, the designs morphed into re-branded sailing gloves, which had already been perfected. Example: a few years ago the marine outfitters all began selling climbing-style seat harnesses for work in the rigging. Harken rep at the Annapolis Boat Show had the cheek to tell me that they had engineered in additional abrasion protection, as though the deck non-skid was more abrasive than a granite boulder! They are easily twice the price of a top-quality big wall harness sold for rock climbing.

So often vendors pretended they've had invented something new, while simply marking-up something that has been perfected in a different application over many years. In the case of climbing gear, UIAA standards set the bar for all of the fall protection standards that followed:

UIAA Standards for climbing equipment. Standards Downloads

Recently the sailing industry has started to catch-up, though only a few short years ago they were woefully behind, yet still charging premium prices.Safety at Sea Harness and Tether Testing

Finally, a few more relevant standards, for those who crave detail. and back-up documentation:

ISAF on Jacklines
http://www.sailing.org/tools/documents/OSR2010Mo1101209-%5B8154%5D.pdf

ISO harness and tether standards
http://jsaf-anzen.jp/pdf/ISO_12401_2009%28E%29-Character_PDF_document.pdf

The point is this; much of the BEST equipment for jackline and harness systems is available from rock climbing equipment sources, not marine stores. The history is longer and and the QC is better. It's not all about price.


Multihull vs. Monohull Caveat: all of my comments are directed towards families with 27- to 40-foot cruising catamarans. I'm staying with what I know. Specifically regarding jacklines, some of what I will say is all wrong for other boats. You have been warned.

Marine vs. Climbing gear Caveat: Not all climbing gear is appropriate in a marine environment. Not all marine gear is suitable for crew retention. This may be a matter of function or materials of construction. For example, rock climbing seat harnesses are not designed to serve as deck harnesses and are dangerous for that purpose (they'll drown you, dragging through the water), and conventional solid gate climbing carabiners are not corrosion resistant and will seize after repeated exposure to salt water. Some climbing gear--slings, wire gate carabiners, bolt hangers--is of superior design for either environment. We'll try to keep the distinction clear.

Crewed Boat vs. Single Handing  Caveat. If you are single handing in anything other than warm inshore waters, assume getting separated from the boat is certain death. Keep your tethers very short and don't plan to release under any foreseeable circumstance. If you are on a crewed boat in moderate conditions, you may want to release if you are dragged, may use a longer tether, and may do without a tether entirely. A PFD alone may be safer. But as night falls, the water temperature drops, and conditions become wild, even crewed sailors may feel falling in is a death sentence. So we must realize there are a continuum of situations and more than one right answer.

Personal Testing Caveat. I have tested all of the theories presented here, either rock climbing or on the water. Be very careful if you take this approach.

Personal Responsibility Caveat. My blog, my rant. I deviate from the conventional wisdom here and there, with reasoning that satisfies me. I have very extensive experience climbing and mountaineering, am very comfortable on-deck, and am very comfortable with this style equipment. But ANY equipment can be misused, and I've seen very good quality marine safety equipment rigged in an unsafe manner. Just because you bought the best from a catalog doesn't mean you know how to apply it. Read everything, learn the engineering, visualize the forces involved, and be careful.

Capsize Caveat. A tether on a sailing dingy or beach cat would deserve a Darwin Award. What about a sport boat driven hard or a high performance multi-hull driven to the limit? Certainly a high priority needs to be placed on releaseablity. But be warned, recent testing suggests not all quick-release attachments work under load and that some are not accessible once PFD inflates. Practical Sailor Magazine is investigating this one. For cruisers, I think this is minor concern.

Jacklines. On monohulls, where these must lay on the deck, webbing is the most popular choice since it won't roll underfoot. If that is where the lines must run, then there is little choice in the matter. However, in many ways webbing is exactly the wrong material.

Durability. Any outdoor rock climber has seen many examples of webbing that have been left on a cliff somewhere to back-up a rappel anchor; after 15 years of sun exposure, they can often be removed with a good yank, their strength reduced from over 4,000 pounds to a few hundred pounds. The general consensus is that blue tubular webbing looses about 15% of its strength per year in continuous exposure in temperate latitudes, and that lighter colors weaken more quickly.  Rope is a far more durable material, since there is more thickness for the UV to penetrate.  Numerous long term endurance tests have been performed on braid and core ropes; generally at least 55% of the strength of the line derives from the core, and even after 10 years of use and 10 years of sun exposure, at least 60% of the strength remains. Good Old Boat and Practical Sailor have both done this sort of testing on old docklines. Still, I wouldn't push it beyond 5 years in a safety-sensitive application.

Ease of clipping. Webbing can be fussy, hanging up on the gate when I least want it to. Rope is lightening fast, particularly when paired with climbing carabiners.

Hand hold. Webbing is poor by comparison.

I use jacklines as a single hander because I don't like the idea of my boat sailing to England on autopilot. A PFD is not going to bring help and I'm not sufficiently optimistic to think help will find me.  In cold weather a PFD is little help unless someone actually sees you enter the water.

I don't understand the habit of rigging jacklines only when needed. "When needed" is pretty often:

• When you go on deck alone, at night outside of the cockpit.
• When the wind is over 15 knots.
• When a thunderstorm blows up.
• When something needs repair in an awkward position while underway.
• When the chute is up.

In other words, nearly every day when cruising. Jacklines should be permanent, like seatbelts, and rope jacklines can be set permanently, like the rest of the boat's rigging. They should not be a temporary measure or an afterthought; they should be a designed part of the boat suitable for everyday use without getting in the way. You need to practice with them.
Once I watched a video of an ocean racing boat losing a man overboard (he was recovered, with some difficulty). It wasn't very rough; he simply was less than mindful of the action around him, was not clipped in, and simply slid across the cockpit and between the life lines (the center line had been removed in the quest to save weight). The main reason people don't clip in, right behind not taking the dangers seriously, is that it's a hindrance. That may have been a factor. Like many racing boats the cockpit was a cluttered mess of ropes and the jackline went over and under the many control lines. The jackline and tethers were a safety after thought, not a reality that the boat or sailing practices were designed around or a reality that the sailors trained with. Removing the center lifeline was just plain stupid. If you're going to use jacklines and tethers on your boat you need to practice with them, day after day, integrating them into the flow of lines and work so they are NOT a hindrance but rather a useful part of the rigging. Climbers are tied in all the time, and we spend years working out systems and routines that prevent us from getting caught up in our knitting.

Spare Halyard as Jackline--Don't Do It. I have heard of a spare halyard being used as a tether in fair weather only; nothing to add, nothing to trip over, and easy to get back on deck. I tried it. If there is enough slack in the halyard to reach the bow sitting down, then when standing on the cabin top there is enough slack to wrap the halyard around the spreaders. In a monohull, you will swing out over the water and drag until the boat tacks. This system is unsafe.

Location. Multihulls have a huge advantage when setting jacklines; they have a wide bow area. A common rational for having very tight jacklines is that the working area at the bow goes to zero and the sailor must to be held very tight to stay on the boat. He is safe from excessive jackline impact forces because he is not going to fall/slide far enough to generate them. Multihulls also have a disadvantage in that there is a lot more deck to cover, and that means longer tethers. Longer tethers mean longer falls and more fall energy. A tether of adjustable length, with multiple clipping points or 2 legs, is required.  Mine have 2 clipping points: one very long where I can reach everything from either jackline, and one much shorter. I use the former in fair weather (when the only risk is tripping over my own feet) and the latter when it's nasty. both options are long enough to be remain clipped to the jacklines while re-entering the cockpit.

Even with adjustable tethers, this additional beam means the multi-hull sailor must design for greater impact energy.


The jackline in the photo is not rod-tight, though there is less slack than it appears. It can be moved about 12-inches side-to-side. They are 5/8-inch dock line and will retain sufficient strength through 5 years of continuous exposure. They are not underfoot and they can be clipped from the cockpit.

My jacklines are attached to the inboard edge of the tramp about 4 feet back from the beam, and to through-bolted hand holds on the hard top. The front beam could hold any load. I am certain the hard-top supports would distort at peak load, but not fail completely. This compromise makes sense to us, as it places the jackline in a safer position; we recognize this. The jacklines run above the deck, serving as a second railing, and we use these and the life lines as twin railings when going forward.; if you pull upwards against them, rather than lean on them, they add much stability. They are not under foot on the side decks as you walk around the side of the cabin. The side decks are also free of genoa tracks and sheets; these are farther aft, in a non-traffic area. Each boat will present its own challenges and solutions, so don't feel tied to convention. Experiment, but think it through from an engineer's view point. Do be certain that all attachments are through-bolted. Lifeline stanchions, for example, are too often only screwed into a rotted wooden block. Two 5/16-inch bolts or a single 3/8-inch bolt with a good backing are a conservative design basis to achieve 5,000-pound strength in shear (assuming a 1/4-inch solid glass deck--with cores or thinner decks consideration must be given to compression and shear).

Be certain the tethers will not allow a fallen sailor near a prop, a deadly hazard on any boat with a transom mounted outboard. This is not an issue on the PDQ because the engines are well forward and inboard, but it was a serious concern on any boat with a transom mounted outboard.

Be certain the tethers do not allow the sailor to go out of reach of the transom. Self rescue will be impossible. Better, see if you can go over the side, and if you can, see that you can get back on board with the boat moving.On boats with high freeboard, it is generally impossible, even for a fit individual.

A center jackline is another option; I've seen this on a Gemini and it looked practical. On one hand it would be impossible to fall over the side, but on the other, there is less security against being washed to leeward when on the windward side. I do not believe it is as safe on a monohull, which leans. Although there is a new fad, suggesting lifelines should be run down the middle, I have not heard any stories of folks falling of the boat uphill, to windward. It just doesn't happen. A windward jackline is safer because you are farther from the leeward rail. Just make sure you work from the windward line as much as possible.

Children. This generation grows up being belted into a car and wearing bike helmets. My daughter grew up, starting when she was crawling, wearing a harness and tether on-board. She liked it, and Daddy led by example. I much prefer tethers to PFDs for kids. They get more freedom, and Dad doesn't have a stroke every time a little one leans near the edge, gazing at the waves, or stumbles near an edge. Harnesses are much cooler on hot days--when it's 100F and humid, requiring a PFD means staying home. A parental eye is still required, and the harness must be fit  so securely that Houdini couldn't escape. Yes, the law requires PFDs for small children. We very seldom did--they are so uncomfortable for small one--but we used the harness every time. However,harnesses often require some customization; this harness had an extra webbing adjustment added in the back, as the original design was insecure on a small child.

Shock Absorption. Rock climbers rely on both climbing rope stretch to prevent a very short fall from generating impact loads well into the thousands of pounds.  The body can absorb only so much, and the anchor points can only withstand so much. I once had this conversation with the gentleman who was fitting tight stainless steel cable jacklines to his 45-foot yacht, in preparation for a trip to Bermuda.  I explained to him that because his cables were strung guitar string tight, it would take only a modest force to pull the anchors right out of the deck.  He assured me that all components could take a 5,000-pound strain. I asked him, would he mind if I gave the cable a good strong yank, just with my hands, as a test.  He said "knock yourself out--don't hurt yourself. Those fittings can hold a car." I wrapped a rag around my hand, gave a sharp tug, and snapped the 1/4-inch high-strength shackle holding the cable to the aft pad eye. He couldn't decide whether to be mad at me or embarrassed. I apologized anyway, but for a few dollars it was a cheap lesson. He grumbled something about "defective parts." (The 1/4" shackle had a rated breaking strain of 4,400 pounds and a SWL of 1,450 pounds, I was told. After muttering something about "defective equipment" he replaced the 1/4-inch shackle and turnbuckle with a high tech lashing. I'm still not sure he got the point, since the entire system had been strained to the very limit by a weakling.)

A jackline should never be made from material with no stretch (OK monohull guys--breath deep. This is catamaran advice, and the rules are a bit different. The jacklines are inboard and there is no skinny bow.). A jackline should never be rigged absolutely tight. Think of it this way; a jackline is like a tight rope, and the less deflection that is permitted the greater the initial tension of the rope must be.  If only a 5% deflection is achieved, then the applied force is multiplied by about 10 times. You can slice the data many ways with engineering calculations (Sample Calculations for Jacklines); it becomes clear that 200-pound sailor that is propelled across the deck by a breaking wave or loses his balance falling off a wave in just the right way will cross the deck at a modest running speed. His body must have at least 2 feet to decelerate or the stress on the jackline will exceed 5,000 pounds and something will break. That stretch must come from the jackline or from a special shock absorbing tether. Not one of those self-retracting tethers sold at the marine store with a shock cord down the middle and not one of the new tethers with an over-stress indicator; a tether designed with sacrificial stitching for use in climbing or the construction trade. These sacrificial tethers were invented by rock climbers (see Yates Ice Screamer to the left above) and grafted into the construction trade. Most of these begin absorbing force in the 400-800 pound range and extend several feet when fully expended; about right for this application. I wouldn't be at all surprised to see marine tethers adopting this feature in a few more seasons, implying through advertising literature that it's a new invention and not just a new application. The new marine tethers have one row of expendable stitching that indicates over stress but does nothing to reduce the stress. A poor and confusing design choice, in the eyes of OSHA and the climbing community. Rather like closing the barn door after the horses have left; "Oh, see here, your harness nearly failed", rather than preventing the failure.

The longer the jackline, the less stretch is needed, the short the the line the more stretch is needed, within limits. A steel cable or even polyester braid, if employed as a rock climbing rope, would be fatal to the climber; the impact force is too great. A bungee cord would be fatal too; the excessive stretch increases the probability of a ground or ledge fall. For the sailor, the strain on the jackline system must be kept below 5,000 pounds. The strain on the tether must stay below 1,000 pounds to achieve that, which indicates a side deflection of 2-3 feet, which equates to a stretch of about 2-3% at 5,000 pounds of strain. This rules out wire and most high-tech lines if they are conservatively sized. 1/2-inch polyester yacht braid seems about right for catamarans with 30-foot long jacklines. 7/16-inch line would be strong enough, but the extra size allows for aging losses and reduces is stretch into the optimum range. Mine are 1/2-inch nylon dock line and are only 22 feet long--it's what I had on-hand and the math works out the same. Given their size, they will be safe for 7-8 years or until they chafe. For jacklines 40-50 feet long, the math changes and high tech lines should be spot-on with regard to stretch, but the strength requirement goes up to 7,000 to 9,000 pounds. Amazing, but easy to achieve with the new materials. The range of calculated answers is broad, because of difference in geometries. One size never seems to fit all. I suggest you have an engineer friend take a look at your arraignment with these shock absorption concepts in mind.

You can find sample calculations here: Sample Calculations for Jacklines


Tethers--Construction.Why webbing instead of rope? Rope tethers look a lot like running rigging. Webbing is less prone to rolling under foot. Unlike the jacklines, it won't likely be in the sun enough for UV damage to matter. This is the conventional choice.

Don't use Spectra webbing for tethers; it has too little stretch. Yes, climbers use it for anchors but NEVER where it will be required to absorb the energy of a fall without some rope in the system for cushioning. Used as a cockpit tether, it would be equivalent to steel cable and would damage either the anchor or the sailor. Nylon webbing tethers have a small amount of give.

If you opt for 2-leg tethers--and you should--the lengths should suit your boat. The standard 3'/6' split is really too long for most boats. I use 2' for the short tether (including carabiners), which suits work at the bow and on the side decks, and 8' for the long tether (catamarans have broad bows).

We pre-rig tethers to each side, clipped port and starboard. Thus, if we need to go forward quickly and even if we have tacked since the last tether use, there is always a tether rigged on the required side. As I have stated earlier, we leave the tethers clipped to the jackline when we come off the deck. I should clarify that I very seldom harness in the cockpit; ours is very deep, is surrounded by hard-top supports an winches, and falling out would be very nearly impossible. Consider your individual situation.

What about climbing rope for tethers? In fact, that is my preferred solution, as the shock absorption is much have discussed this at length. However, the downsides are that knotted tethers are bulky and sewing climbing rope is only properly done by people that specialize in climbing rope. It is easy to do wrong. I tested many samples of my work.

 The best option is to buy a 2-leg tether from Kong. The price is reasonable, the Tango clips are the best available, the long leg is elasticized, and the price is not much more than the hardware bought separately.

Tethers--Length and Getting Back On-board. In the best of all worlds tether length and jackline position are such that falling off is not possible. That must be addressed on a boat-by-boat basis due to geometry differences. Often having 2 length options on a tether will help. But let's assume for the moment you can fall over.

Can you get back aboard? With a full crew, someone may be able to man-haul you aboard. Let's disregard that option for the typical cruising family; they lack the horsepower, depending on who went over. There is always the option of cranking them up with the spinnaker halyard. Again, not dependable with a family crew. Not enough hands and not enough horsepower.

I suggest trying to reboard without assistance, with you crew slowly motoring ahead. Don't strain yourself either; this must be easy or it will not work if you are injured or unconscious. Gently--there is no point in risking injury--lower yourself easily over the side and see what works. It will be very difficult. Realistically, the victim is likely to be Dad, as he goes forward to wrestle with the jib in terrible conditions. Poor old Dad. Logically, the answer is to combine this with your MOB hoisting practice, as we have. Fun on a hot day. After this sobering exercise you will probably shorten your tethers.

Tethers--2 Legs are Better Than One. For most boats tethers really need to be adjustable in length; a short leg for the bow and getting past the cabin trunk, and a longer length for use around the mast, and in the case of catamarans, on the foredeck. Being able to clip two points, so that you never unhook, can also be vital. My two-leg tethers are described here.


Carabiners.  Wire gate aluminum carabiners hold up very well, and the anodized ones do best.  Conventional climbing carabiners rapidly seize-up due to corrosion--avoid them.  Locking carabiners must be religiously lubricated or they will also freeze up, though I have had good luck with screw gate locking biners on the jackline end--I am very careful to keep them greased several times each year. Even if they only last 4-8 seasons--I retire them to other uses if there are any signs of wear--I prefer them as they are much cheaper and three times lighter than their stainless steel cousins, which means they are easy on the gel coat. I prefer non-auto-locking biners; those are sometimes fussy and occationally fail to lock in ice climbing and dusty climbing environments. However, many have reported that they are very happy with auto-locking biners on jacklines if kept lubricated. Locking biners are required on the jackline or u-bolt end since there are many obstructions that can force the gate open and un-clip the biner. 

The Kong Tango is a popular tether carabiner, 
suitable for either the harness or jackline end.
However, they do require seasonal lubrication.

The text below is from the ISO standard. All conventional (non-locking) carabiners will fail this test. Why is this not deadly to rock climbers? They do not go in circles around the anchors. The weight of the rope generally holds the biner in a fixed orientation. They clip either to runners (short slings) or purpose-designed bolt hangers that resist this action. And they use locking carabiners where there is some risk or redundancy is lacking.

5.4 Accidental hook opening testing


5.4.1 The tendency of the hook to accidentally become detached from its attachment point shall be tested
using the following three styles of attachment point, made from 8 mm diameter rod:
a) a straight rod;
b) an eye bolt of internal radius 10 mm;
c) U-bolts of internal radius 15 mm and 20 mm.


5.4.2 Move the hook by hand as far as is possible in the following directions with the attachment point mounted vertically:
a) move forward and backward, right and left without any rotation, movement being in the horizontal plane;
b) rotate in the horizontal plane by up to 360° using the attachment point as the axis, rotating both clockwise and anticlockwise;
c) rotate in the vertical plane by up to 360° about the axis of the hook, rotating both clockwise and anticlockwise;
d) rotate in the vertical plane by up to 360° about an axis running through the attachment point, rotating both clockwise and anticlockwise.


The hook fails the test if it releases from the attachment point. If the hook closure mechanism is shown to open but not release, this will also constitute a failure, as release would probably occur with geometry of different dimensions.

No hook will fail a test on an attachment point where its use is clearly and permanently warned against in accordance with 6 g).

Not Spinlock Race Tethers. They can rotate off a U-bolt ...

 

.. Or if pressed against a railing.

This is not so clear on the harness end, so I formerly used ordinary wire gate biners there, though now I use the Kong Tango and like it better. There, I've said it, counter to the "new" conventional wisdom that spinnaker shackles should be used on the harness end so that a sailor can free himself in the event of a roll-over or knock down. I don't care for spinnaker shackles--I've seen too many spinnakers fly away when the lanyard hooked on something or because the locking pin was not fully inserted. My thoughts:

• I am not concerned about a carabiner unclipping from a harness; in 25 years of climbing, I never heard of it. Unclip from fixed anchors, certainly, but not from the harness end. However, we have switched to the Kong Tango carabiners, for a little added security.
• I can clip a conventional biner 100 times, in the dark hanging from a cliff, with gloves on, and never get it wrong; I've done it. Same with the Tango. I'm sure I can't get a spinnaker shackle right 100 times in a row on a nice day on a bouncing foredeck; I've done that too and seen a few sails kite away.
• Clipping a wire gate or Tango carabiner is a one-hand job. A spinnaker shackle takes 2 hands.
• I believe the chance of a capsize on a cruising cat, compared to a knock down on a monohull is much lower. Possible, but remote compared to all other risks.
• I have a great deal of confidence that I can un-hook a conventional biner under load in adverse circumstances; after 30 years of climbing, I am very familiar with the tricks and don't have to think about them. I've unclipped while being dragged beside the boat at 5 knots; not easy, but it took only seconds. I am not prone to panic. Better than risking accidental release.
• Most sailors leave the harness end clipped and unclip the jackline end off when going below. We do the opposite; the harness end is clipped off and the tether remains in place on the jackline for the next user. Otherwise, the sailor would have to go on-deck to clip in. For our boat configuration, this is safer and more convenient. It is also a reason why a carabiner works for us at the harness end. The jackline end is ALWAYS a locking biner.
• It has been suggested that a sailor should always carry a sheath knife to cut a tether loose. My personal guess is that I am more likely to inadvertently stab myself than to benefit from the knife's close proximity. My choice. I do keep a folding knife in my pocket and there is always a knife at the helm.

What does the ISAF have to say about carabiners? "Warning: it is possible for a for a plain snap hook to disengage from a u-bolt if the hook is rotated under load at right angles to the axis of the u-bolt. For this reason the use of snaphooks with positive locking devises is strongly recommended." Very true. In fact, even a locking carabiner or snap hook will fail at a small fraction of its rated strength in that circumstance, since the gate is intended to retain the rope but not to carry cross-loading strain. I have seen gates collapse under little more than body weight. Rock climbers discovered this in the late 40s and it became common practice to connect to fixed points with a flexible sling. If you are going to attach to a fixed point, consider extending the hard point with a short strong sling, allowing the carabiner to ride away from the deck and hardware. In fact, this is much easier to arrange at the mast, helm, or bow pulpit, as often no new hardware is required; only a strong loop, easily rigged and easily removed.

On the other hand, this from a sailor with releasable snap shackles on his tether:
"The replacement tether I bought from West Marine (ISAF Specification Safety Tether, No. 9553504) has a new toggle on the snap-shackle release lanyard that consists of an open triangle of plastic.This is dangerous, in my opinion! In my first few hours of using the new tether, in moderate sea conditions, I managed to
snag the triangular loop on something and release the snap shackle. I am now replacing all triangular loop pulls with bead pulls that I have crafted myself."
This is apparently the reason West Marine now uses the Kong Tango carabiner. I suspect we are going to see a general move away from spinnaker shackles on tethers. We'll see. Everything is a compromise.

There is also this counter point, from Andrew evans, one of the world's most expereinced singlehanders, excerpted from his free on-line book on singlehanding:

_______

Some boaters insist on locking carabiners. I have no problem with this concept as long as they can
be quickly and easily fastened and unfastened blindly with one hand. In nine years of running
all over my boat dragging my tether, I have never had a carabiner detach from the jack lines or my
harness, so I don’t feel that a locking mechanism is necessary. I have heard of situations where the
jack line runs parallel to a sheet and the carabiner runs onto the sheet. My suggestion is to move the
jack line to a new position where this can not happen.

Some races insist on a quick release mechanism for the clip. I disagree with this concept. First, I
have never seen a quick release mechanism that can be easily fastened with one hand. If this can’t
be done, it won’t be used for the reasons mentioned above. Second, I can not imagine the
circumstances were I would want to be detached from the boat. Even if I am thrown overboard and
dragging injured beside the boat, this is a much better situation than watching the boat sail away.
I can see the safety advantage of a quick release on a crewed boat, but not singlehanding.
The tether must be long enough so that the skipper can move from rail to rail without unclipping
during normal tacking or gybing. After a tack, it will be necessary to unclip from the leeward jack
line and clip to the windward jack line in order to walk up the windward side of the boat.

_____

And thus, even with ISAF, the carabiner at the harness end is not required to be locking. Locking is a very good idea--I like the Kong Tango--but it remains a choice.  At the jackline or u-bolt end, I repeat, a locking biner is required by rule, experience, and common sense.

I have heard it suggested that aluminum carabiners are subject to cracking if dropped. There is some minor truth in that, but the caution applies to drops from great heights onto rocks. I've abused biners of many designs on weekly climbing trips, some for 30 years. Two have been retired due to hairline cracks in the gate mechanism; it was a design error that was retired 25 years ago. However, I did pull one of the cracked biners to destruction on a test rig, just to see; it made it to 3,800 pounds. There are no rocks to drop them against on your boat.

Never use a non-locking carabiner as a shackle substitute up in the rigging, for example as a halyard shackle. You'll be hating life when it clips on to the upper shrouds and won't come down! I didn't do it, but I heard the swearing from down the dock. They are nice for hoisting the dingy, securing the boom, and a host of minor conveniences.

Seat Harnesses. For use on deck, climbing seat harnesses are completely inappropriate; in the water they will hold your head under, whereas a chest harness will hold your head-up... sort of. For use up the mast, big wall seat harnesses are best. They were designed for days spent on the big vertical walls in Yosemite. Yates Mountaineering makes some of the best. A few minutes or an hour up the mast is a piece of cake.  The so-called "marine" versions and "riggers" harnesses are just watered down wall harnesses. Also, a harness should fit the individual just as a shoe fits the foot. Go to a store and try the harness on.  Any good climbing store will have a rope that you can hang from for a little while, so your backside can tell you how it fits and your legs can try to go to sleep. Important cautions, marked on the harness:

• The accessory loops on the waist belt are for hanging tools, NOT attaching safety lines.
• Buckling the waist correctly is VERY important; 20 years ago I watched a teenager fall out of a harness from 200 feet up and land 30 feet from me, all because the belt was not buckled properly. It must be snug to the smallest part of the waste in such a way that it cannot be pulled down in the event of an inverted fall. The webbing must double back through the buckle in the require manner and have a minimum free tail length, typically 3 inches (6 inches is better, in case you gain weight or are wearing more clothes).

Chest Harness Fit. I see many worn low and loose at the lower edge of the rib cage. I see this on round-the-world race sailors, but that doesn't make them right, not in this one case. Does it feel safer, like a life jacket? I think so, and it makes it easier to move and more comfortable with foul weather gear. I understand. Still, it's enough to make a climber cringe. Climbers have been killed that way, back in the days when climbers wore chest harnesses. Falls caused a broken ribs and the sharp ends punctured lungs. They need to be worn up higher, nearer the arm pits and certainly above the edge of the ribs. It's likely that if I were sailing the southern oceans for weeks, showered in near-freezing water I would change my tune. I would be a world class sailor and very confident of my abilities. I also have done a good bit of easier (for me) rock and ice climbing without a rope, because it was faster, because it was safe enough for me, and for the thrill of it. That doesn't make it smart; it is a poor habit that experienced climbers can get away with, and it sets a terrible example for new comers.

This poses a challenge for women, something learned as my daughter grew. A full vest of some sort would help, but that is impractical in warm weather and not comfortable the rest. It seems all that can be done if to watch tether length and to wear the harness as high as possible. After I took the above photos I realized the problem and made some adjustments to the fit.

Slings. A staple of the rock climber's anchor inventory, these are sewn loops of various high-tech materials, ranging in length from 6 inches to 48 inches. They can be used for everything from sail tack extensions, to anchors for securing yourself while working at the masthead, to secondary anchor attachment points (prusik hitch them to the rode, and clip the secondary rode to that--it makes untangling after tide swings easier.  A hundred uses that you will only discover over time and perhaps by reading a book on rock climbing. Cheap compared to "marine" alternatives and very strong.

Bolt Hangers. Stainless bolt hangers for climbing are rated at over 5,000 pounds, fit a 3/8" bolt, and can be used many places where you would like to add a strong anchorage point using an existing bolt. For under $2... beat that, West Marine!

Acmeclimbing - Stainless Bolt Hanger 
I'm not generally suggesting these for direct jackline attachments; they present a cutting hazard to webbing (sharp edge--attach the jackline using a shackle or other smooth hardware). On our boat, they work well for cabin-top attachments. Not for use as cockpit tether anchors: they are designed to take load in one direction and parallel to the surface; cockpit tether loads are more variable. Any application would need to considered the above factors.

 

Some Thoughts from Charles Kanter. A guru of catamaran sailing.  Jack Lines. We seem to agree on most everything, for catamarans, except my desire to keep jacklines rigged at all times. He too promotes inboard lines using dockline. I guess we've kicked the same rocks.

I hope you have enjoyed my ramblings; they were just a few ideas I wanted to share.  I've been involved in roped climbing and mountaineering for over 30 years, been on thousands of routes all over the country on both rock and ice, and fallen on a rope thousands of times. I have tested my ideas and never had a major gear failure. In other words, I have had gear failures and learned from them, and always had backup systems in place that were adequate. Just as every sailor should be a solid swimmer, I believe every sailor should learn the basics of climbing and fall protection in order to understand the systems involved. I have not provided that knowledge here. Take a class - you may like it enough to give up sailing. Think of all the money you'll save.

There's nothing like a nice frosty icefall! Sizing-up a New Hampshire waterfall a few years ago.