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Quieting the anchor chain's 'crunch and grind' in the bow roller



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What is the issue?
In a stiff breeze or chop, a yacht tends to press astern lifting up the weight of chain between the vessel and the anchor. Once the chain is pulled taught the links in the chocks snap tight and then grind and crunch.

Why address this?
The grinding and crunching noise reverberates through the vessel and can be very annoying, particularly so for crew trying to rest or sleep in the fo'c'sle cabin. The hard snapping on the chain can also cause the anchor to dislodge.

How to address this?
Place a damping ‘snubber’ line on the anchor chain to add some bounce and eliminate the metal-on-metal at the stem of the boat.

A ‘snubber’ line is a length of nylon warp with typically a chain hook set into one end for convenient connection to the anchor chain. When deployed the snubber is made off to a strong mooring point on the boat and the chain hook is attached to a link in the anchor chain. In a light breeze having about 3 metres of snubbing line is acceptable. Pay out some more chain until the snubbing line is taking all the anchoring load, then feed out a few additional feet of anchor chain. Allow the yacht to lay back and ride upon the snubber and the chain that leads down to the anchor beyond its attachment point.


Yacht without a snubber
Photo: Michael Harpur


Critically, you must lock off the extended anchor chain so it can take the load should the snubber attachment come off or fail. It is also recommended that a protective PVC hose pipe is added to the snubbing line in the position where it comes upon against chocks or fairlead in order to prevent chafe - see protecting warps.


Yacht with a snubber
Photo: Michael Harpur


When the vessel then lays to the combined snubber line and chain a soft damping bounce is added to the snatching yacht. Hence the anchor is not whipped up so hard and there is no anchor chain coming taught and grinding upon the chocks. It also removes anchor chain rumble where the sound of the chain sweeping over a hard bottom comes up into the boat via the chain, similar to a 'tin can telephone', and which keeps you awake at night.


A rolling hitch is just as good as a chain hook
Photo: Lucasbosch via ASA 3.0


The primary purpose of a snubber is to reduce loads on the ground tackle and boat by adding elasticity to the rode. It is an essential piece of equipment to weather an anchorage in a seaway and I would not consider cruising without one light weather snubber with a chain hook and two long lines earmarked for the purpose when it gets really rough.

Standard Eye Grab Hook
Photo: Courtesy of Campbell
Then the snubber truly comes into its own stretching to reduce the peaks of the sudden shock loads of wind surges and the waves striking and rising the boat. Without a snubber or set of snubbers in these circumstances, the anchor chain is likely to break, the anchor jerked free of its holding or a cleat could be ripped out of the deck.

Whilst trapped in a lagoon we survived a hurricane on a single 1'' braided nylon line after our anchor chain had long since broken away. We watched a nearby boat ride through all this without any of our drama on two anchors with two long snubber lines taking the load off the chains, and the protected anchor chains to fall back should the snubber lines break. When Darwin said “It is not the strongest of the species that survives, nor the most intelligent; it is the one most adaptable to change” he surly foresaw a nylon rode used as a shock absorbing snubber. So after that experience, I would always have two long snubbing lines, of a boat length and a half long, that can double as nice and bouncy dock lines. Then when the wind kicks up I would attach them with rolling hitchs to two anchors and at their full length so I can maximise their shock absorbing stretch.


Mantus Chain Hook
Photo: Courtesy of Mantus
All that is required to make a snubber is to buy a length of three-strand nylon line or double braid nylon dock line. Using nylon line is important because it will allow for the most stretch. The warp thickness will depend on the boat’s weight, too heavy a line will not stretch, too light will break. A reasonable gauge is the size of line that would be appropriate for the vessel's mooring lines.


A variety of hitches may be used for attaching the snubber to the chain, but a rolling hitch can be relied upon to never slip or prove too difficult to undo. The rolling hitch has several advantages over a chain grabbing attachment. One of the primary advantages of the rolling hitch is that it will not damage the chain's galvanize or cause wear to the chain. It can be made fast and taken off the chain, inboard of the bow roller which is generally easier than leaning out past the bow to attach a chain hook - although removal of the chain hook is often easier as it is only a matter of shaking it loose when the line is not under load.


Wichard
Photo: Courtesy of Wichard
Also the rolling hitch will not rust, will not fall off and can free the line up to be used for a different purpose. It costs nothing and the time dedicated to learning it for this purpose will come in very handy when it is used as a stopper to relax the tension on a sheet so that a jammed winch or block can be cleared - this knots' most other common usage aboard.


However, a spliced in chain hook is optimal for line strength and it also makes it much easier to attach and detach. Products made of stainless steel avoid the rust issue. The standard Eye Grab Hook, used by the vast majority of cruisers, can fall off in when not kept under constant tension which is problematic when being used in areas with shifting winds and currents. The falling off issue can be resolved by variations of the chain hook such as the Mantus Chain Hook, with its slot configuration and retainer, or the Wichard with a locking set-pin to keep it in place. Both of these hooks securely latch onto the chain and will not fall off even when chain is unloaded.


A snubber, or even better a set of snubbers, are truly an essential addition to your ground tackle as you can never underestimate the ability of that bounce in the line to give way when needed. They will help you sleep easy in many more ways than just reducing the bump and grind at the chocks.

With thanks to:
Michael Harpur, Yacht Obsession.




Deploying a snubber




Anchoring with a snubber in developed conditions




Mantus Chain Hook


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