PS Seeks Input on Harness and Tether Design

Posted by Darrell Nicholson at 02:29PM - Comments: (9)

March 13, 2012

 

We’ve received some good suggestions from readers in response to my editorial in the March issue of Practical Sailor that described our tether and harness design project. Similar to what we did with toddler life jackets back in 2007, the plan is to solicit input from experts in the field, other sailors, and PS readers to try to come up with an improved design for inflatable PFD/harnesses. Because the tether is such an integral part of the PFD/harness when sailing offshore, we plan to work on improved tether designs as well.

While this project has been simmering in the back of my head for a while, it became a high priority in the wake of the WingNuts capsize in last year's Chicago Yacht Club Chicago to Mackinac Race. We will be reporting on that accident in detail in the April issue, which should be available online soon.

As a first step in this project, we’ve done some preliminary research in the water. A few weeks ago, Technical Editor Ralph Naranjo and his wife, Lenore, dropped by our office in Sarasota, Fla., and we took some time to re-test a few of the inflatable PFD/harnesses that PS had previously tested. We wanted to see what sort of problems would arise in extreme situations when a person was caught beneath the hull of a boat or dinghy with his PFD inflated.

A fully inflated PFD/harness can be tight around the neck, even without bulky clothes underneath.

Granted, the chances of this happening to any sailor are extremely rare, but it has happened before and will no doubt happen again. Our experience with similar, more likely, scenarios such as trying to climb back aboard with a fully inflated PFD, suggested that this capsize scenario was an event worth looking into. Could you escape? If too much buoyancy is a problem, how long would it take to deflate the PFD?

If you visit many of the sailboat racing websites these days, you’ll see an active discussion regarding auto-inflation versus manual inflation on a PFD/harness. Some sailors disarm the auto-inflation feature because they worry that an accidental auto-inflation caused when the PFD/harness gets wet—either from rain, sea spray, or boarding sea—could put them at risk on deck. This is something to consider. Our own testing has found that some self-inflating PFD/harnesses will inflate when the harness is simply doused with a hose. The most resistant types were the hydrostatic releases, such as those designed by CM Hammar, which are triggered by a pressure change caused by complete immersion.

Anyone who is considering disabling the auto-inflation feature is probably aware of the most obvious consequence—if you are knocked unconscious, your PFD won’t inflate. But there are two other consequences that you should be aware of. First, the pull-tab on the manual inflation may not be so easy to grab and pull in an emergency. These are small plastic pull tabs and if you are wearing a lot of clothing or panicked, you might suddenly find yourself treading water, unable to inflate your vest.

Secondly, you should be aware of what is called the “gasp reflex.” This can occur when a person suddenly hits the water—particularly cold water. Instead of holding his breath, the victim gasps and ingests water, and this reflex that can result in drowning. We have little idea how many of the existing auto-inflate designs would prevent the ingestion of water in a “gasp reflex” incident. However, an auto-inflate device would still be more likely to save person’s life who had experienced this reflex. At least the auto-inflate PFD/harness would give the victim a second chance to recover with his or her head above the water.

Another point worth mentioning: If you typically sail with foul-weather gear and/or insulating layers under your PFD/harness, you should inflate your PFD sometime while you are wearing these clothes as a test. You will likely find the compression around the neck to be startling, enough to incite a brief moment of claustrophobic panic.

Finally, on the topic of tethers. If you have a tether with both short and long “legs” to attach to the boat, you should not "stow" the loose, unused leg by attaching it to the harness clip-in point. If you have to release yourself from the tether, you are making it doubly hard to get free because you now have not one but two clips to undo. Some people loop the loose leg over their shoulder, or put it on a velcro loop. One solution is to attach the loose leg to a point on the tether itself, but few designs we’ve seen offer a convenient place for this. This, in our view, is one of the many problems in this type of gear that still needs resolving.

I invite anyone who is interested in contributing expertise or suggestions to our PFD/harness design project to contact me directly at practicalsailor@belvoirpubs.com.

 

 

Comments (9)

We test a variety of non-USCG approved buoyancy aids in the July 2013 issue. The only one our testers found as practical for diving would be the Sea Tee, from Float-Tech. It is basically a manually-inflatable rash guard/swim shirt.

Posted by: Darrell | June 9, 2013 4:34 PM    Report this comment

Way late to this party, but just now seeking a custom PFD because nothing exists that is what I want. As a diver who has spent untold hours in the eastern Pacific, sometimes in serious chop, waiting for a tender to collect me and as someone who's "girls" provide quite the frontal buoyancy, I was hoping to find something akin to a BPW (backplate wing)BC that could be used. Doesn't exist and why not? Makes a lot more sense to me. Think inflatable PFD with the lift in the back and the harness in the front. Many accessories attachable by d rings. Often too hot for foam PFDs. May have to fashion my own USCG approved or not, I think it would be more effective in the water and more comfortable out of the water. Will have to be only self inflatable. Not sure any PFD is going to keep an unconscious person's face out of the water.

Posted by: LeslieDTG | June 8, 2013 10:37 AM    Report this comment

Why is it that Americans seem to think that the only way to make something float is to pump it full of air? Inflatable PFDs, infatable dinghys, inflatable life-rafts ...?

What happens when they leak? How do you get them puffed up in the first place? In an emergency.

We should focus on things that require no gadgetry to get them bouyant, i.e.foam filled vests, jackets, etc.

Amen to the comment about crotch straps. Unless you are built like Charles Atlas (remember him?) the usual thing (including the 'Lifesling' slips right over your shoulders -- as has been reported)

And the comments about looking elsewhere are spot on -- skydivers, rockclimbers, F1 and NASCAR drivers, river rafters and even roofing contractors, have been perfecting this gear for years while the yacht jewelry merchants, tha ABYC and the US Coast Guard have contributed nothing.

Posted by: K F | March 19, 2012 3:32 PM    Report this comment

I agree with Dick Tietjen. The vest type PFD (various models by Stearns and others) is nearly ideal for 95% of sailors who know they need a PFD but who cannot be convinced to wear one. For all the reasons Dick describes, I wish it were the industry standard. These vest-type PFDs are also near-perfect for guests (as well as crew) who are otherwise reluctant to don a conventional or inflatable PFD when asked to do so.

It's time for the industry and the USCG to get "vested" with these models, while continuing to seek their improvement.

Captain Bernie Weiss AtlanticYachtDelivery.com

Posted by: Captain Bernie Weiss | March 19, 2012 11:19 AM    Report this comment

In response to the broken "D" comment above:

It is actually more probable that the forces exceeded the rated strength of the system (5,000 pounds). This sounds far fetched, but rock climbers understand very well that with no stretch in the system, a 3- to 5-foot fall can generate forces that rip webbing and biners apart. The g-force is terrific. I'm guessing the sailor was tethered in the cockpit and was thrown over the rail, the impact force exceeding 5,000 pounds. Had he fallen over the side on a jack line, the force would be less, since jack lines stretch.

OSHA requires that all tethers include sacrificial shock absorbing sections; stitching that rips out of folded sections of webbing, limiting the peak load to a more manageable 600 pounds. This is a VERY inexpensive feature; another few feet of webbing and some bar tacking.

There is little point in making the equipment much stronger, since a 5,000 pound impact will seriously injure the sailor. It makes more sense to make the system softer, like providing crumple zones in cars.

Posted by: Unknown | March 16, 2012 2:58 PM    Report this comment

I would like to lobby for mandatory crotch straps on all PFDs.

I have had two occasions where people on my boat were wearing PFDs when they went overboard. As they hit the water they instantly and instinctively raised the arms above their heads and the PFD slid right over their head and off of them. Unfortunately both people had reservations about going out on a sailboat beforehand, I am quite certain they will not be back for more as it was a truly frightening experience for them. Interesting neither would trust an inflatable PFD, however I think the inflatable would have been more likely to have stayed on them. A crotch strap on the PFD would have certainly kept it on them.

Posted by: Weekend Sailor | March 14, 2012 10:46 PM    Report this comment

Regarding conventional non-inflatable PFDs. One design that has been suggested for possible cross-pollination into the offshore sailing sphere are the whitewater rescue jackets used for swift rivers. These are not inflatable jackets, but they do have harness/belt for attaching rescue lines (in the back) and the belt is designed to be releasable under load. Bulk and discomfort (particularly in tropical climates) would be downsides to this approach.

Posted by: DARRELL N | March 14, 2012 1:56 PM    Report this comment

Hello there,

In regards to PFD design, some thoughts and questions.

My SO has issues with her inflatable PFD regarding fit, reliability, clothing capability, etc.

She has gone back to her Stearns workvest type because it's light, thin, fits and still functions under outerwear, insulates as well as breathes, and acts as body armor, needs no activation for flotation, and has no servicing requirements.

What it doesn't do is integrate a POB harness, wave hood, or self right.

Why aren't we seeing these small modifications in current models of non inflatable PFDs?

Also, what's to stop us from taking example from the skydiving and aerospace people regarding quick release equipment. There has to be a ton of technology out there to draw from.

Question re D ring vs O ring has to do with why we can't make a D that will outperform an O at close to comparable cost?

Thanks for the time.

Best Regards,

Dick Tietjen

Posted by: Dick & Mary T | March 14, 2012 11:58 AM    Report this comment

A lesson in harness and tether construction can be learned from Tami Ashcraft, who along with a sailor friend was making a sailboat delivery to Hawaii when they ran into a powerful storm. Ashcraft was knocked unconscious. When she came to more than 24 hours later, she climbed to the cockpit where a single tether dangled over the side. The D-ring had snapped where it was connected to her friend's PFD. He was gone. Ashcraft was convinced a round ring might have held, like those on Mustang vests.

Posted by: David Liscio | March 13, 2012 3:59 PM    Report this comment


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