Wednesday, February 28, 2018

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.

Sunday, February 18, 2018

100 Best--Chapter 15

Safety Gear

Seven years ago I posted this rant about the notion that you could buy safety and some of the ridiculous things new sailors are persuaded to believe they need. Safety comes from understanding your situation and knowing your limitations. However, there is equipment that comes in handy from time to time.

86. PFDs. In fact, I don't wear these very much. For the most part, I rely on a harness and tethers. I do wear a PFD when whitewater kayaking and occasionally in the dinghy when condition suggest it. But mostly I try to stay out of the water.

I have an aversion to automatic inflating PFD's. As a singlehander, I may need to climb back on board, and doing anything to help yourself in an inflated PFD is comically awkward. I also don't understand the likelihood of falling overboard unconscious and surviving that. The boat is not going to stop and no one is going to help me back aboard. Thus, as a singlehanded sailor I find that absurdly unlikely.

In fact, it is simple to convert automatic PFD's to manual. In the case of the Spinlock Pro series, it is a $20 conversion kit.

87. Harnesses.  The key factors are fit and band width. The strap must fall on the sternum; lower and you can't breath, higher and it will try to choke you. It must be warn snugly enough so that you feel it when you inhale--otherwise, it can slide over your shoulders. What about crotch straps? In fact, I have a new design that will be in Practical Sailor in a few months. Instead of a ball-crusher, it is fully fall-rated (I took numerous vertical falls up to 6 feet in testing).

The other key factor is the width of the band. 45 mm is the standard minimum, but wider, up to 4 inches is proportionally better. Try hanging from the harness before you buy and you will understand. According to the UIAA and OSHA, hanging from a chest harness for more than 30 seconds can cause permanent injury to the nerves in the arm pits.

88. Tethers. Big article this month in PS. It seems the old standby Gibb design has been modified from the original pattent numerous times until it no longer performes at all as originally inteneded. Unfortunatly, the manufacture didn't think to test this. Failures have been documented at forces as low as 275 pounds (bent sideways).

Instead, choose either the Kong Tango (West Marine, Kong, Glow Fast, or DIY), Wichard Proline (only Proline tethers), or one of several via ferrata rated clips. These are rated at 1800 pounds sideways.

89. Jacklines. and Hard Points. The tether has to attach to something, and a system of jacklines and hard points is the answer. In "SingleHanded Sailing for the Coastal Sailor" I discuss this in length. I also have articles coming up in Practical Sailor. In the image below, for example, my tether is attached to a bolt hanger hard point on the hard top with a Kong Tango carabiner.

Recovering a Delta Drogue 7. It's surprisingly easy to fall off when working hard with both hands.

90. Drogues. Perhaps you are in a major storm and would like a little downwind stability. More likely, you either need to slow down to make some repairs or need emergency steering. A drogue is a compact solution, though proper use is a complex conversation. I've published numerous articles in Practical Sailor and discuss this at length in "Faster Cruising for the Coastal Sailor."

The Delta Drogue is the best value. However, there are two things to be aware of. The size, though often described as the diameter by retailers, is actually one of the cloth dimensions before sewing, and the actual diameter is one third of the model number. For example a Delta Drogue 72 is approximately 2 feet diameter. Second, I would go up one size from factory recommendations. Drogues in general, are more stable in storm conditions when sized conservatively. The exception to this, is if you intend to use the drogue for emergency steering. However, conservatively sized drogue is still useful; simply haul it in close so it does not fully immerse in the water, limiting drag.

 My favorites are the Sea Brake GP 24 for storms and the Gale Rider 36 for emergency steering.


Navigation? GPS is nice, but I do quite well with a paper chart and a sharp eye. Coms? VHF is obligatory and a cell phone is a powerful compliment. The one time I needed to speak with the Coast Guard I used the cell phone, which was much better. AIS and radar? I suppose it depends on visibility and traffic.

A solid boat helps. I don't mean a "blue water boat;" I mean one that reliably does what you think it will. If the conditions are getting out of hand, leave.

Without question, the most important safety asset is your head. Don't get in situations that require safety equipment. Navigate conservatively. Watch the weather. Make sail changes early. Learn the many ways sailboats are built to adapt to contingencies (sail vs power, and don't forget anchors).

Thursday, February 8, 2018

Bump Setting an Anchor

Just as it is Chesapeake Bay lore that you soak an anchor in soft mud to increase holding (I've been studying time effects for upcoming Practical Sailor articles and as a book topic), in hard bottom areas it is common practice to use the momentum of the boat to help drive the anchor point home.

Doesn't everyone go swimming in the Chesapeake in March (48F water)? A dry suit and hood make all the difference.

But how much force is actually delivered to the anchor, for how long, and does it work? So yesterday we headed out to a nice find sand bottom in Herring Bay and proceeded to "bump set" the anchor at different speeds (1-3 knots) and with two different bridles (both 35 feet long, but 8.3mm and 12 mm).

Eyeballs up-close will always be the best way to investigate an anchor. Normally I detest anchor buoys and tripping lines because of fouling potential, but they make finding the anchors and confirming geometry a lot easier when testing. Small fenders work, just be certain the float is not lifting the anchor!

Although I'm still crunching the numbers, the basic rules of thumb seem to be these:
  • Only fine sand. Coarse sand takes a gentler hand, and soft mud requires long undisturbed periods and a soft hand.
  • Long snubber, at least 30 feet. Try this with all-chain and you will pull the front of the boat off. The "whump" will also be to brief to move the anchor. 
  • About 1.5 knots for monohulls and about 2.5 knots for catamarans. This will be equivalent to 60 knots or wind, give or take, assuming the snubber design I posted in Practical Sailor.
  • Two bumps is enough. The anchor didn't move appreciably after that.
  • For outboard-powered boats and engineless boats only. If you have a good inboard, just set with that.
I tested at up to 3.5 knots, in the interest of science, and the forces are impressive perhaps twice what my ground tackle has seen in the nastiest thunderstorm. The bridle stretched a good 6 feet in the process, buffering the impact and maintaining the force for several seconds. As a result, the rode tension never exceeded 50% of the working load limit of the chain and shackles.

Before testing I ran all the numbers on an excel sheet, including all I have learned about rope elasticity, damping, anchors, and wind loads. When all of the data were collected and processed, it turns out the calculations were right and I had not learned anything that actually required field testing. But I like seeing actual numbers on a load cell.

Friday, February 2, 2018

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.