20mm nylon snubber failure - well not quite.

[rgano]

Simi, you are doing your proper due diligence in your inspection of our mooring tackle. Well done, sir.

[Simi 60]

Originally Posted by rslifkin

If you start to experience a similar failure again, it may be time to up-size the snubber a bit. With larger line you'd need to make it longer to get enough stretch, but the end product wouldn't be loaded as close to its breaking strength, so it would last longer and you'd be less likely to develop a failure like this quickly (meaning more chance to notice the problem before it fails entirely).

The 20mm is fine and has served us well in all conditions thrown at us over the past 6 years of full time cruising.

It's us that was the issue
We should not have left the short snubber on in boisterous conditions, we don't usually.
But, now we know it's limit.

We have a short snubber for 95% of our anchoring needs simply because a longer one starts going green when in the water after several days - short one stops at water.

[SailorGreg]

Originally Posted by Capt Ray

Here is a pic of my snubber with a rubber shock absorber in-line:

https://shellerina.com/2020/09/21/splicing-8-plait/

I really believe it helps in the job a snubber is supposed to do.

I think this approach is much better than relying on stretch in the line. With this, the snubber can be sized stronger than the chain and the dock edge absorbs any shock loads.

[Comodave]

Originally Posted by Porgy

I’ve read in a few places and from a couple old salts that using hose or plastic tube for chafe is not good. The abrasion of nylon strands as they are stretched and contract under load is a large contributing factor in chafe. The plastic hose prevents water from cooling and lubricating the line at that point. Just a thought.

This. You want a porous chaffing guard so the line can get wet and cool down.

[Simi 60]

Originally Posted by Comodave

This. You want a porous chaffing guard so the line can get wet and cool down.

Where does the water come from?
It's not always raining when it's blowing.

[Comodave]

Originally Posted by Simi 60

Where does the water come from?
It's not always raining when it's blowing.

Not always but if it is storming it may be raining. But if it is waterproof then no water can get in even if it is raining.

[Porgy]

Originally Posted by Comodave

Not always but if it is storming it may be raining. But if it is waterproof then no water can get in even if it is raining.

That, and I could’ve swore I also wrote that plastic hose inhibits the heat escaping but guess my typing fingers weren’t keeping up with my brain.

[cafesport]

Simi, How much longer did it measure from original, I’m guessing you exceeded the working load by more than 30 percent. Also what’s the bend radius of your chock? From the photo there are a few different things happening which is why we switched our snubbers from twisted 1” and 3/4” to 5/8” 8 strand plaited nylon. We have also replaced them at least yearly since they are always exposed to the sun or submerged for weeks in the water. Between the critters, salt and uv they get pretty rough by the end of our summers. We use 3 snubbers of known elasticities and an adjustable one which can brace any or all of the others as needed. Our shortest one is set up for winds up to 35 knots and in use lives under water. As the snubbers wear and stretch they get too long to stow in their normal positions on deck so we know exactly when it’s time to make new ones. Stretch is a pretty good warning flag.

SailorGreg, I’ve mentioned it before on here that with sufficient catenary you don’t ever need a snubber….until you do, and that’s why we almost always put ours out. Ours was big and heavy and a bit of a pain to rig so I decided there must be a better solution. I’ve found using smaller stretchier snubbers allows the chain catenary to be available at higher wind loads than you would normally expect to see. A stretchy snubber sized a bit lighter than the chain’s catenary force becomes the first line of defense against chain and anchor snatch loads. We usually anchor with enough chain catenary for 35 knots and our no 1 snubber stretches around 10% at this wind speed. Once the sustained wind exceeds 35 both the catenary and the snubber work side by side until around 50 knots. If we expect greater than 40 knots we start with our number 2 snubber. No 2 stretches 10% at 50 knots but has sufficient length to absorb the waves that come with these winds. We then brace our number 2 with our number 1 so 2 5/8” snubbers one loaded to 10% and the other to 20% and we still aren’t yanking on the chain or anchor.

[JP2]

SIMI: We switched from the clear PVC chafe guard to the wire-reinforced version and saw a huge improvement in protection. (9/16 size on 55,000 lbs with chain slotted SS plate)

Also noted previously the heat from friction was with the PVC movement against the hawse hole surface and not so much from the nylon line, internally. So your's looks very unusual from here.

Have also used CHAFE PRO for a 3 ply nylon towline for years. Can't say enough about that product and its longevity. Well worth the price.

[Simi 60]

Had the same happen with the storm snubber after a sustained blow for several days a month or so back.

Am experimenting now with
20mm nylon from Sampson post to about a foot behind the roller with a thimble and eye splice
From there and over the roller in Dyneema
Then back to a thimble, eysplice and 20mm nylon in whatever length needed given the weather.

Thinking we can then not worry about the hose cover and the dyneemas superior chafe resistance will hopefully be the end of the problem.

[Mako]

Not a bad idea Simi. Short leader of Dyneema or even just old-fashioned chain, pretty much eliminates the chafe guard-fire hose part of the equation.

[jclays]

I normally don't have any chafe protection on my lines. I make sure that my deck chocks that my line runs thru is clean and smooth. I check my lines at every visit if I'm at the docks. If I'm on the hook or a mooring ball I check several times a day and before bed. I'll reposition lines if the water has been bumpy and there has been plenty movement if only to change points of strain. I don't like not seeing the rope covered by the chafe protection.

[Hippocampus]

Line heats up under strain. Particularly bad if covered and cycling strain/no strain. Some would argue it weakens line over time. Others say covers trap salt crystals and dirt. They say those can cut the fibers of line when it cycles strain/no strain. In spite of this have used discarded fire hose at times. Nylon isn’t abrasion resistant and will chafe quickly and badly. Fortunately not that expensive so can be replaced without a mortgage. Ideally a snubber run should have no chafe points so need no line protection but sometimes unavoidable. I purchased some very thin bendable SS plates with adhesive on the back. That does provide a very smooth surface and allows avoiding a covering. I do play a hose on dock lines whenever I can. In the tropics then spray them with bug killer (bop) and after it rains. No cockroaches.

[Comodave]

Originally Posted by Hippocampus

Line heats up under strain. Particularly bad if covered and cycling strain/no strain. Some would argue it weakens line over time. Others say covers trap salt crystals and dirt. They say those can cut the fibers of line when it cycles strain/no strain. In spite of this have used discarded fire hose at times. Nylon isn’t abrasion resistant and will chafe quickly and badly. Fortunately not that expensive so can be replaced without a mortgage. Ideally a snubber run should have no chafe points so need no line protection but sometimes unavoidable. I purchased some very thin bendable SS plates with adhesive on the back. That does provide a very smooth surface and allows avoiding a covering. I do play a hose on dock lines whenever I can. In the tropics then spray them with bug killer (bop) and after it rains. No cockroaches.

I use the Davis Chafe Protectors. They are heavy duty nylon with Velcro to hold them in place. They will let water into the line they are protecting so it helps keep the lines cooler and help prevent overheating of the line. I have not had the nylon covers get any significant wear. But they are sacrificial anyway. They are simple to put on and I have never had them come loose.

[Simi 60]

Originally Posted by Comodave

I use the Davis Chafe Protectors. They are heavy duty nylon with Velcro to hold them in place. They will let water into the line they are protecting so it helps keep the lines cooler and help prevent overheating of the linee.

Again, only any good if you have rain
Which we have not

Originally Posted by Hippocampus

Ideally a snubber run should have no chafe points so need no line protection but sometimes unavoidable.

Ours runs over a shiny, smooth roller made from some form of hard plastic of about 4 inch radius.
There is nothing there that is abrasive

I think it's a point load thing

The Dyneema seems to be handling it fine, just a bit freaky seeing this big meaty 20mm ending and pencil thin dyneema going over the roller.

[Comodave]

Bucket of water???

[Simi 60]

Originally Posted by Comodave

Bucket of water???

Sleep?

We have a deck hose..

[Comodave]

Originally Posted by Simi 60

Sleep?

We have a deck hose..

If you soak it before you go to bed it will likely stay wet most of the night. If not when you get up to check the anchor wet it down again. You do get up to check the anchor, right?

[Simi 60]

Originally Posted by Comodave

If you soak it before you go to bed it will likely stay wet most of the night. If not when you get up to check the anchor wet it down again.

But if using salt water it could be argued that salt becomes an abrasive in itself

If using dyneema there will be no water retention anyway, but it also has superior chafe/abrasion resistance.

You do get up to check the anchor, right?

Nope, it's way down there doing its thing, but I do check the snubber on occasion during a prolonged strong wind period
It's how I picked up on the issues in the first place

[cafesport]

With that bend radius I don’t think you have point loading problem. I think it was a simply a two snubber night and you only had one out. That’s exactly what three strand does when it’s overworked.