Confused about snubbers

[SV__Grace]

Originally Posted by and4ew

But if my anchor chain is attached to anchor rope and then to my boat doesn't the rope act as a snubber?

It seems like you might be confused because you have chain/rope rode, which is a rope rode with a short length of chain at the anchor. Is that correct?

If so, you are correct that you don't need a snubber.

Those of us with all chain rode use snubbers because-

- takes the force/load off the windlass
- provides more stretch when needed in higher winds/strong currents
- greatly decreases shock loads on the anchor, lessening likelihood of anchor dragging or pulling out in rough conditions when the boat is bucking and sailing all around

And I'm sure there's more reasons and benefits, but those of us who prefer the security of a chain rode need to use a snubber in all but the most benign anchoring conditions.

[Pete7]

Originally Posted by Mike OReilly

And for the record, what I thought people were referencing here is this kind of thing:

We use a rubber snubber on our line. At 5000 kgs we bounce a bit even in a gentle swell so it just smooths out the tugging motion. 10mm 3 strand can have a jerky motion if a speed boat or jet ski goes past.

The rubber is left over from when we had them on the shore lines after I switched to the metal spring type for the shore lines. The rubber ones only last us about 2 years before the rope cuts into them.

Downside with the metal ones is they squeak after a while but a shot of WD40 shuts them up for a peaceful nights sleep.

The other advantage to the snubber line is the weight is taken off the chain so it doesn't slide backwards and forwards grinding the GRP on the deck 3 feet above your head at night

Pete

[thinwater]

One more thing is worth mentioning regarding rope/chain rodes, when the chain is longish. It needs to either all-chain with a snubber, or at least 30 feet of rope.


There have been failures when there was only ~ 10 feet of rope deploy (the balance being chain) and the chop got steep. This is simply not enough length for the rope to absorb the energy. Rope snubbers for chain should ideally be longer than 10 feet, but people can use shorter snubbers with chain for two reasons: catenary absorbs some of the shock and if it breaks not all is lost. With a mixed rode you need more rope length.


Either all chain, or at least 30' of rope (more is better).

[Dockhead]

Originally Posted by Chotu

I had reasoned that the rubber shock absorbers would make a good addition to my snubber/bridle system. I was using them with 3/4" rope and they actually snapped apart in just a few weeks.

I don't think they're up to the task.

Just like with nylon, the rubber snubbers have a load limit which if you exceed will drastically shorten their lives.


I never use them for an anchor snubber, but find them exceptionally useful for docklines for damping motion in bad weather. I don't put them on the main dock lines, but I have three extra lines set up with snubbers, which I place here and there to control motion.



For an anchor snubber, you need to tune them. I keep a variety on board of different lengths and diameters. Just like with the rubber ones, if you have a light, short one which stretches more than x% of its length, it will snap. If you need more stretch, then you need a longer and larger diameter one. Snubbers less than about 10 meters long are not much use, at least on my boat.


NEVER EVER rely on a snubber as the ultimate connection between the chain and the boat. Snubber is meant to stretch, and that creates risks of chafe, heating, and so forth which means they do fail. Besides the snubber you must have a chain lock or strong strop connecting the chain to the boat.

[Dockhead]

Originally Posted by thinwater

One more thing is worth mentioning regarding rope/chain rodes, when the chain is longish. It needs to either all-chain with a snubber, or at least 30 feet of rope.

There have been failures when there was only ~ 10 feet of rope deploy (the balance being chain) and the chop got steep. This is simply not enough length for the rope to absorb the energy. Rope snubbers for chain should ideally be longer than 10 feet, but people can use shorter snubbers with chain for two reasons: catenary absorbs some of the shock and if it breaks not all is lost. With a mixed rode you need more rope length.

Either all chain, or at least 30' of rope (more is better).

But note that snubbers fail unexpectedly even when loaded reasonably. Nylon while stretching is exceptionally vulnerable to chafe, also will be weaker than specified when wet.

[thinwater]

Originally Posted by Dockhead

But note that snubbers fail unexpectedly even when loaded reasonably. Nylon while stretching is exceptionally vulnerable to chafe, also will be weaker than specified when wet.

No argument there. With chain rodes I follow ABYC guidance, but with rope rode I will always go up a tick for durability and grip.

[Dockhead]

Originally Posted by thinwater

No argument there. With chain rodes I follow ABYC guidance, but with rope rode I will always go up a tick for durability and grip.

If you use rope rode, do you use nylon or polyester?


I always found this very persuasive: https://www.petersmith.net.nz/boat-a...right-rode.pdf

[rslifkin]

Originally Posted by Dockhead

If you use rope rode, do you use nylon or polyester?


I always found this very persuasive: https://www.petersmith.net.nz/boat-a...right-rode.pdf

I've seen a few things about polyester anchor rode. But at the same time, it seems hard to buy. Finding polyester 3 strand isn't too hard, but I've never found appropriately sized 8 plait or similar.

[Dockhead]

Originally Posted by rslifkin

I've seen a few things about polyester anchor rode. But at the same time, it seems hard to buy. Finding polyester 3 strand isn't too hard, but I've never found appropriately sized 8 plait or similar.

It's often called "Brait" in the U.S., and it's not hard to find.


E.g. https://www.downwindmarine.com/Intre...-90890023.html


I strongly prefer octoplait for anchor rode as it doesn't hockle, and has a much nicer hand. And yes, polyester, not nylon. Polyester also stretches and I find that polyester anchor rode is stretchy enough not to need a snubber.

[tomfl]

Originally Posted by Dockhead

SNIP
NEVER EVER rely on a snubber as the ultimate connection between the chain and the boat. Snubber is meant to stretch, and that creates risks of chafe, heating, and so forth which means they do fail. Besides the snubber you must have a chain lock or strong strop connecting the chain to the boat.

Good point.

[CarlF]

While I use nylon 8 plait (Yale Brait) for the anchor rode above the chain, I think three strand nylon is best for snubbers because it's cheap and stretches a lot. It also chafes less than my Brait. A snubber should be considered a consumable. I replace mine regularly.

I also use a much smaller line diameter than many. A snubbers needs to stretch to do its job. On a 55ft 50,000lb motorsailer, I use 30ft 7/16" nylon as the primary snubber.

I also have a 2nd snubber of 5/8" nylon that I use in storm conditions. It is tied to the chain so that it only starts to tension after the 7/16" primary has stretched 2ft

While I used a rolling hitch for years to attach to the chain, I now attach a 18" piece of 1/4" dyneema to an eye splice in the end of the line. I tie the dyneema with a bowline through a link in the chain. This is a bit faster than the rolling hitch and never slips.

[Jim Cate]

Originally Posted by Pete7

We use a rubber snubber on our line. At 5000 kgs we bounce a bit even in a gentle swell so it just smooths out the tugging motion. 10mm 3 strand can have a jerky motion if a speed boat or jet ski goes past.

The rubber is left over from when we had them on the shore lines after I switched to the metal spring type for the shore lines. The rubber ones only last us about 2 years before the rope cuts into them.

Downside with the metal ones is they squeak after a while but a shot of WD40 shuts them up for a peaceful nights sleep.

The other advantage to the snubber line is the weight is taken off the chain so it doesn't slide backwards and forwards grinding the GRP on the deck 3 feet above your head at night

Pete

Pete, you might try using motorcycle chain spray lube on those squeaky snubbers. It is very thick and sticky when applied and should last longer than WD40 which is a lousy lubricant at best.

Jim

[Pete7]

Originally Posted by Jim Cate

Pete, you might try using motorcycle chain spray lube on those squeaky snubbers. It is very thick and sticky when applied and should last longer than WD40 which is a lousy lubricant at best.

Jim

Oh like that idea and there are now modern silicone chain lubricants available. The WD40 was an emergency solution when I was instructed by SWMBO to get up and STOP that squeak at some ungodly hour in the night

[and4ew]

Thanks for the great info. So next question is: should I use snubbers and/or bridles if I have a bowsprit where the anchor leads out over the end of it? The boat is new to me (Bayfield 29 Cutter) and I think the PO just ran the rode and rope out over the end of the bowsprit. This seems to be to potentially put a lot of unwanted leverage on it. Hopefully my pics will explain better. What should I do?

[SV__Grace]

Originally Posted by and4ew

Thanks for the great info. So next question is: should I use snubbers and/or bridles if I have a bowsprit where the anchor leads out over the end of it? The boat is new to me (Bayfield 29 Cutter) and I think the PO just ran the rode and rope out over the end of the bowsprit. This seems to be to potentially put a lot of unwanted leverage on it. Hopefully my pics will explain better. What should I do?

Beautiful boat! You have a small second roller next to your primary bower that looks good for a snubber, though I agree that it's not optimal.

My boat has a similar arrangement and if you search for "Obsessed with snubbers" you will find a description of my setup, which I recommend you consider-

Primary/storm snubber- bridle running through your bow chocks, each leg 30-40 feet so you can let out more when needed during a storm. I use chafe protection against rubbing on the bobstay, but it's probably not needed. I've seen boats with a PVC pipe over their bobstay for this.

Secondary snubber- I recommend cow hitching a low friction ring to your waterline bobstay connection and running the line to the bow for adjustment. I use a lighter, stretchier line for this than my storm snubber, and deploy in settled conditions, crowded anchorages requiring short scope, and as a lazy backup to my storm snubber so that if it were to break this would take up the load long enough for me to take care of the situation.