An anchor rode snubber is a length of fairly elastic rope placed between the bow roller and the anchor chain. It has several purposes:
1. It disconnects the metal connection between the seabed and the forecabin, thus eliminating the noise of the chain dragging across the bottom that would otherwise disturb the people sleeping there.
2. It transfers the anchoring load from the windlass that would otherwise be subject to snatch loadings and clutch slip, or even links jumping across the gypsy teeth.
3. Snatch loadings generated by waves and yawing in stronger winds are damped, providing more comfort to the yacht occupants and reducing sudden anchor loads that would break it out of the seabed.
Nylon has more elasticity than any other rope type and is the preferred option for a snubber. The rope’s construction is also important, three-ply and octoplait having more elasticity than braid-on-braid. Rope diameter needs to be selected carefully to match the size of the boat, perhaps after some experimentation, to ensure that appreciable stretch takes place. As a guide, the snubber on my 35 ft boat is 12 mm in diameter and I can watch it extending by 10 – 15 cm over a 3 metre length in fresh conditions. I know of boats up to 55 ft that use a 19 mm octoplait snubber. Some data for nylon climbing rope suggests that it can stretch by up to 40% without breaking.
Such amounts of stretch can cause wear where the snubber passes through fairleads or over a bow roller. We protect ours by passing it through plastic hose but another option is to include a Dyneema strop at the rubbing point, although this adds complexity and may take some time to set up.
Rubber snubbers, or even steel springs, are primarily intended for shock absorption in alongside berths but they are sometimes used as snubbers. They would undoubtedly be more difficult to deploy and are less elastic than nylon rope.
The energy absorbed by stretching the rope is dissipated as heat. I have never heard of a melted snubber line but deterioration over time is inevitable and it is a good investment to change it every couple of years.
Connection to chain
The easiest attachment method is a custom designed hook. Our original one was formed from wire but it bent and released the chain in severe conditions. We replaced it with a wrought stainless steel one that seems far stronger. Some people report these falling off the chain in use, although this has not been our experience.
Shackles offer a positive attachment, although conventional ones may need to be undersized to allow the pin to pass through a link. Specialist shackles overcome this drawback by taking the arms around a link instead of through it. These advantages come at the price of greater difficulty when retrieving the chain, whereas hooks will often drop off before reaching the bow roller. At worst, a bent shackle pin could severely affect removal of the shackle. Never try to haul a shackle through the bow roller, which will inevitably result in damage.
A recent idea is to use a Dyneema soft shackle, overcoming most of the disadvantages. A soft shackle passes easily through a link, is very strong and has outstanding wear and cut resistance. Dyneema also has good UV resistance.
A rolling hitch is the preferred attachment method for many skippers. My opinion is that this is probably perfectly adequate for occasional use but I would prefer something better for the frequent anchoring that we are used to. On our cramped foredeck there is little opportunity for tying knots.
Setting the snubber is simple and should take no more than a few minutes. Having deployed the appropriate chain scope for the depth of water and conditions, connect the snubber to the chain forward of the bow roller and let out chain until the snubber reaches the waterline. When using an open hook you will need to keep tension on the rope so it does not fall off. Cleat the snubber at this point, with 2 – 3 metres deployed, run out a little more chain so that it hangs in a loop, then cleat it. As the wind increases it is worth extending this length by connecting the inboard end to a midships cleat instead of the forward ones. Some owners attach the snubber well aft, giving up to 15 metres of elasticity. If you take the more obvious measure of simply letting more snubber and chain out there is a risk that a hook will contact the seabed as the boat surges, which will release it from the chain.
Recovery of chain hook
The beauty of a simple forged train hook is that it simply falls off as soon as the chain is hauled in taut. The video shows it well.
Other snubber uses
When berthed stern-to on anchor, typical in Greece and some other parts of the Mediterranean, an elastic snubber is definitely not what is wanted. But it is still necessary to unload the windlass. We use a Wichard chain hook with a catch in coordination with a heavier 3-strand nylon warp.