Anchor Snubber

[richardbayle]

Quick to complain, quick to praise.
I bought an Anchor Snubber last May from West Marine and regretfully it failed whilst anchored off Dominica two weeks ago. I wrote to Davis Instruments pointing this out and instead of just saying it was my fault as I used to much slack in the chain allowing the full strain to be taken by the snubber; they did point this out by the way, they immediately moved to replace it by asking West Marine to send another.
Due to the high cost of postage to the Caribbean, Niels Kisling of Davis even offered; probably tongue in cheek, to personally deliver it.
Brilliant service, great product despite the issue with it, it actually does work very well. So impressed.
Thought you all should know

 

[RupertW]

Quick to complain, quick to praise.
I bought an Anchor Snubber last May from West Marine and regretfully it failed whilst anchored off Dominica two weeks ago. I wrote to Davis Instruments pointing this out and instead of just saying it was my fault as I used to much slack in the chain allowing the full strain to be taken by the snubber; they did point this out by the way, they immediately moved to replace it by asking West Marine to send another.
Due to the high cost of postage to the Caribbean, Niels Kisling of Davis even offered; probably tongue in cheek, to personally deliver it.
Brilliant service, great product despite the issue with it, it actually does work very well. So impressed.
Thought you all should know

Good service but weird advice. The idea of a snubber is to take the full force. The chain is supposed to be completely slack so that even with the snubber at full stretch the chain remains slack so no force on the windlass drum.

 

[Robin]

Good service but weird advice. The idea of a snubber is to take the full force. The chain is supposed to be completely slack so that even with the snubber at full stretch the chain remains slack so no force on the windlass drum.

+1:encouragement:

 

[mainsail1]

Good service but weird advice. The idea of a snubber is to take the full force. The chain is supposed to be completely slack so that even with the snubber at full stretch the chain remains slack so no force on the windlass drum.

I always thought you stop the chain on the windlass brake/ let the chain out under power and then put the snubber on.

 

[RichardS]

Good service but weird advice. The idea of a snubber is to take the full force. The chain is supposed to be completely slack so that even with the snubber at full stretch the chain remains slack so no force on the windlass drum.

It depends what kind of snubber it is. A length of large diameter line is meant to take the full strain as are those metal spring snubbers but the rubber "snakes" are not supposed to, I don't think.

Richard

 

[dunedin]

It depends what kind of snubber it is. A length of large diameter line is meant to take the full strain as are those metal spring snubbers but the rubber "snakes" are not supposed to, I don't think.
Richard

We use rubber snubbers both for the main winter mooring ropes and the anchor snubber. The Ines we use the mooring/snubber rope is threaded through then wrapped around the rubber section. Hence should be able to take the full strain of the rope - and if the rubber fails it simply falls back to using the rope.
And like others we let the anchor chain out so that no strain ever on the windlass (but with a second/rope hook to take over if the main snubber ever parted). Seems odd advice - and indeed feels odd to buy rather than make up an anchor snubber

 

[RichardS]

We use rubber snubbers both for the main winter mooring ropes and the anchor snubber. The Ines we use the mooring/snubber rope is threaded through then wrapped around the rubber section. Hence should be able to take the full strain of the rope - and if the rubber fails it simply falls back to using the rope.

But wrapping the line or chain around the snubber is not the same as having a loop of free line or chain hanging down between the two ends of the snubber.

Richard

 

[MM5AHO]

I use Nylon rope as a snubber, a chain hook on one end, a loop of slack chain boat side of the hook, and the rope runs across the deck aft to a cleat to get about 10m of rope. It stretches more than a metre.

 

[wizard]

I use Nylon rope as a snubber, a chain hook on one end, a loop of slack chain boat side of the hook, and the rope runs across the deck aft to a cleat to get about 10m of rope. It stretches more than a metre.

I do exactly the same, only with 11m of multiplait taken outside the cleats to the stern cleat.

 

[NormanS]

I always thought you stop the chain on the windlass brake/ let the chain out under power and then put the snubber on.

What does that achieve?

 

[mainsail1]

What does that achieve?

I think I have misunderstood the OP. I was thinking of a chain stopper.

 

[vyv_cox]

My understanding of rubber snubbers is that they are particularly useful at shock absorption, i.e. the short sharp blows that might be expected in short lines attaching a boat to a pontoon or a wall. Their elasticity is not very high due to the formulation of the rubber compound, which makes them less suitable for anchoring, where the movement of the vessel is greater but the shock loading is less. Testing of rubber snubbers against nylon rope in anchor rodes suggests that the latter make for far more comfortable living aboard.

 

[Paddy Layback]

I use Nylon rope as a snubber, a chain hook on one end, a loop of slack chain boat side of the hook, and the rope runs across the deck aft to a cleat to get about 10m of rope. It stretches more than a metre.

May I politely ask out of interest:
It's been drilled into me to stay clear of towropes, and lines under tension in general.
A friend took a D-shackle in the brain when a stretched nylon towline let go. (He lived, just).
I appreciate that all relates to tugs etc not yachts.
I would be wary of nylon under tension along the sidedeck, do you take any precautions? Not starting any argument, just asking, cheers.

 

[MM5AHO]

The main precaution I take is to use an appropriate size rope.
The theoretical load on my boat at F8 is about 300 kg (varying up and down). With a 2000kg rope, I have some head room. A whipsnapping rope is one thing, but a piece of steel on one end is quite another. But the direction the hook might take if the rope snapped isn't straight along the deck. That piece of rope is at the rode angle (depth dependent), and a rope break would mean that side of the break would go away from the boat into the water, leaving the boat hanging on the chain only. So that leave me with half a rope potentially whipping to stern (if it broke), but outside the cockpit. I don't take any specific precautions for that.

 

[Paddy Layback]

The main precaution I take is to use an appropriate size rope.
The theoretical load on my boat at F8 is about 300 kg (varying up and down). With a 2000kg rope, I have some head room. A whipsnapping rope is one thing, but a piece of steel on one end is quite another. But the direction the hook might take if the rope snapped isn't straight along the deck. That piece of rope is at the rode angle (depth dependent), and a rope break would mean that side of the break would go away from the boat into the water, leaving the boat hanging on the chain only. So that leave me with half a rope potentially whipping to stern (if it broke), but outside the cockpit. I don't take any specific precautions for that.

Aha yes I get you , thanks for that.

 

[NormanS]

Right, let's say you have a 10m length of suitable sized nylon as a snubber. What, if any, are the perceived advantages of having it rigged along the deck, as opposed to having it all overboard? Personally, I can see several disadvantages of having it rigged on deck: chafe, clutter, not having a clear line for it etc. What good points are there?

 

[RupertW]

Right, let's say you have a 10m length of suitable sized nylon as a snubber. What, if any, are the perceived advantages of having it rigged along the deck, as opposed to having it all overboard? Personally, I can see several disadvantages of having it rigged on deck: chafe, clutter, not having a clear line for it etc. What good points are there?

I have combination of rubber snubber (with 2m nylon rope with chain hook wrapped around it) and a 15m nylon warp which I attach when needed. If I'm in a tight anchorage where dropping back 10m (or even temporarily going forward 10m to attach the chain hook further along the chain) is difficult then I lay the warp along the side deck to the stern cleat where is rubs only against the sidedeck surface but can stretch.

Where possible though I release the longer warp over the bow.

 

[MM5AHO]

Right, let's say you have a 10m length of suitable sized nylon as a snubber. What, if any, are the perceived advantages of having it rigged along the deck, as opposed to having it all overboard? Personally, I can see several disadvantages of having it rigged on deck: chafe, clutter, not having a clear line for it etc. What good points are there?

I'm note sure of any advantages of having it on deck. I suspect its habit that started when I tied a string on the rope (like they do in a tug of war) and watched in fascination as it moved. I have approx 10m rope and the point just aft of the bow, moves up to a metre in a blow. That's about 10% elongation.
I've never really though to have it all in the water, but can't seen any reason why not, other that it will get wet.

I doubt that any rubber or spring type snubber has that much elongation.

 

[SAWDOC]

The main precaution I take is to use an appropriate size rope.

The theoretical load on my boat at F8 is about 300 kg (varying up and down).

Can anyone advise on how that is calculated approximately? I have a 33 footer with high topsides which seems prone to high windage but how to calculate a loading figure?

 

[Saguday]

Have a read here:

Alain Fraysse - Rode forces

Useful if mathematical blog which allows you to work it out yourself or use one of his built-in calculators.

Fr'instance, he derives the force on the rode as approx F = KxL^P*V^2 where K=0.0089, P=1.66, L=boat length in metres, V=wind velocity in knots.

For my boat approx 12m long and and 50 knots of wind that's 1376kgF (or decaNewtons). Interestingly this is about the SWL of the anchor swivel on my current bower anchor rode. Alain goes into lots of other factors that affect anchoring in fascinating and intimate detail, well worth a read.

Another place to have a look is the Knox anchors site - the example given there is a 12m yacht in F8 experiencing a rode force of around 400kg but note it's proportional to Vsquared so my 50knot F10 example is 3-4x higher load - eek.