A snubber is the length of rope that takes the load off your chain while you’re anchored. If your rode is all chain, you need one. If you already have plenty of rope deployed as part of the main rode, that rope is doing the same job and a dedicated snubber is optional.
Chain doesn’t stretch. As the boat pitches and veers, every one of those movements arrives at the anchor as a shock load rather than a gradual pull. That raises the peak load on the anchor, which is what makes an anchor drag that would otherwise hold, and it over-stresses the chain itself.
Rope stretches. A snubber absorbs the movement and hands the anchor a smoother load.
There’s a second benefit that owners of smaller boats notice first. A snubber stops chain rumble, the noise and vibration that travels up the chain and into the hull. In a forepeak or a forward berth that noise can be severe. Some people prefer to hear it, because chain rumble is also feedback about what the chain and anchor are doing on the bottom.
Length
Use a minimum of 10 m (30 ft), or half the boat’s length overall, whichever is longer.
Go shorter than that and, depending on rope diameter, you get very little shock absorption. It will still quiet the chain rumble and the roller noise, but it won’t do much about the loads.
Leave enough slack in the chain for the rope to stretch. If the chain stays taut behind the snubber, the rope never extends and no shock absorption takes place. This one is easy to underestimate.
Attaching it to the chain
Tie the line directly to the chain with a rolling hitch. We prefer this to a chain hook.
A rolling hitch retains most of the rope’s strength, spreads the load across several links, and doesn’t wear the chain. Tie it around the outside of a link, then secure the working end with one or two clove hitches further down. The clove hitches don’t need to be tightened. They’re just controlling the tail. It takes a little longer to attach and remove than a hook does.
A chain hook brings three problems with it.
It concentrates the whole load onto one link, pulling in a direction chain isn’t designed for. Claw types made from bent bar can open up under strain, which makes the hook the weakest link in the system. And a metal claw working against a link is hard on the galvanizing and causes real wear over time.
If you do use a hook, don’t splice the rope directly through the hook eye. That’s a weak point. Splice through a thimble and join it to the hook with a shackle. The shackle now carries the full load, so use a good one.
Chafe protection
Your snubber runs over a roller or through a chock under load, and that’s where rope fails. Fit chafe protection<LINK TO chafe protection> before the snubber goes into service.
Rubber snubbers
Purpose-made rubber snubbers are available, and they solve two problems that a long rope snubber creates. <image – can we find one?>
They work at a much shorter length, which helps in shallow water or a crowded anchorage where you can’t give up the swinging room. They also cut the slingshot effect a long length of nylon can introduce, where the boat surges forward as the stretched line recovers.
They usually come with a short length of rope already integrated, so attaching one to the chain and to the boat is no different from a rope snubber.