Rethinking Anchor Snubbers

Posted by Darrell Nicholson with Jonathan Neeves at 07:36AM - Comments: (11)

Jonathan Neeves
Jonathan Neeves

In this bridle arrangement, the individual snubber legs are joined at a shackle with scaffold or halyard knots (climbing rope is impossible to splice). A chain hook attaches to the chain. Our tests show that some chain hook can reduce the chain's breaking strength by more than 40 percent.

What length, diameter, and type of snubber do you use? What do you need?

The main purpose of a snubber is to reduce loads on the the anchor and boat by adding elasticity to the rode. Usually made of three-strand nylon, the snubber joins a strong point on the boat—usually a cleat or a bit—to a link in the anchor chain. In between these two points the chain is slacked to allow the snubber to stretch. If a boat uses a mostly nylon rode, a snubber can still be used to reduce chafe at the bow roller, hawsehole, or chock.

You can use a variety of hitches for attaching the snubber to chain, but a hook makes it easy to attach and detach. As wind and waves lift the anchored boat, the snubber stretches to reduce, if not eliminate, any shock loads that might jerk the anchor free of its holding or rip a cleat from the deck. In theory, the snubber sounds simple. In practice, there’s a lot more than meets the eye.

Over the years, Practical Sailor has been collecting information on boats that have dragged anchor and wound up lost or in peril. The results of many of our anchoring studies can be found in our ebook on anchoring and mooring, as well as in our online archives. To anyone who has spent a night pitching in an exposed anchorage, it would be no surprise to learn that in many dragging incidents the snubber parted, or was stretched to its limit—allowing the chain and boat to absorb some teeth-rattling shock loads before something finally gave.

Based on the information we’ve gathered, PS testers have devised a series of tests to explore the topic of snubbers in greater depth. Some of their findings run contrary to popular assumptions regarding snubbers. In the March 2016 issue of Practical Sailor we look at two of these assumptions.

The first assumption is that an eight to twelve-foot long snubber is more than enough to absorb the loads when a squall rolls through an exposed anchorage. The second is that using a snubber hook has no effect on the strength of the chain. It turns out that both of these assumptions can lead to trouble.

The topic is one that interests me personally. One of the most harrowing nights I ever spent aboard my 32-foot ketch Tosca was when she diving into steep chop among a small fleet of squid boats in an exposed anchorage near Thailand. Sustained winds blew well over 25 knots, gusts blew much higher. One after the other my snubbers snapped.

On two separate occasions, squid boats, straining under their own anchors, bore down. Being able to adjust the anchor rode, yet still absorb the shock loads in the shallow (less than 20 feet) anchorage became a round-the-clock job. I finally settled on a length of 3/4-inch diameter three-strand nylon used for a kedge and deployed about thirty feet (Tosca weighed in at 12 tons). The engine ran through the night.

How long should a snubber be? What material? And what about diameter?

The upcoming issue will answer these questions in greater detail, and I think even long-time subscribers will be surprised what we find. For the moment, I’m hoping that you can tell us about the snubber arrangement you use for your own boat, and how it has performed. (You can leave your comments below, or send your comments to me at practicalsailor@belvoir.com) Here’s an example of the snubber used by one of our contributors Jonathan Neeves, who carries out many of our anchor and rode tests. Neeves uses this setup on a seven-ton, 38-foot catamaran that he sails in Australia.

After some rough calculation of loads, Neeves concluded that a snubber of about 30 feet long was the minimum he would need to absorb predicted loads at anchor. While it is hard to envision the idea of a 30-foot snubber extending forward from the bow, it need not extend 30-feet forward of the bow, as he describes below.

On most catamarans, the snubber is a bridle that extends outward from the bow cross beams and attaches to the anchor. Our bridle is formed using two 50-foot long lenghts of lightly used 11 millimeter climbing rope (selected for its abrasion resistance and elasticity) and attached to horn cleats on the stern. (The equivalent would be 12-millimeter nylon three-strand braid or eight-strand plait, either of which would serve well.)

We run the snubber up the side decks, through the stanchion bases. The legs of each bridle then pass through swivel blocks shackled to pad eyes that we have installed at each bow. Although each snubber is fifty feet long, we only use about 30 feet; the rest is in reserve.

The individual snubber legs are joined at a shackle with scaffold or halyard knots (climbing rope is impossible to splice). The only tricky part of the installation is reinforcing the area where the pad eyes are located. An alternative to the pad eyes is to fit the blocks to the forward horn cleats. (We used to do this, securing the blocks with a length of nylon webbing so that they hung outboard.)

The same system can easily be adopted for a monohull that uses a single snubber. The main variable is how to direct the snubber from the side deck to the chain hook. This will depend on the individual yacht, but fairleads would be an attractive option, probably requiring some form of chafe protection.

If you have a beamy or heavy monohull, a bridle can be more effective at reduce yawing, and yawing can exacerbate snatch loads. The amount of time, you invest in developing a sensible system will depend on how much time you spend at anchor. We can be at anchor for three to five months each year so we wanted something permanent. 

Look for a complete report on snubbers and chain hooks in the March 2016 issue of Practical Sailor.

Comments (11)

I have seen mentioned that the snubber should NOT be led over the bow roller. Why is this? I find that doing so leads the snubber in a more direct line with the boat and reduces substantially the yawing in stronger winds. I would think that chafing would be reduced as the roller would move with the line. Where am I wrong?

Thank you,

Posted by: Alebrije | April 18, 2017 5:31 PM    Report this comment

On Acorn, a Hinckley Bermuda 40 yawl, 20,000 pounds displacement, we have anchored out well more than a hundred times in all conditions. We have a 45 pound CQR on a bow roller for primary anchor, with 250' feet of 5/16 Campbell hi test chain. This setup has only dragged once, in a Maine coast anchorage during a squall storm with something like 35-40 knots of wind. We have tried a lot of snubber setups over the years, and now settled on a 55 foot long piece of 5/8" Yale nylon 8-strand Yacht Brait with a SS chain hook spliced into one end. (That kind of splicing is a dicey business). Typically we will let out chain to a scope of 4 or 5 to one, reverse engine to set the anchor, then hook the snubber onto the chain and bring it back aboard through the starboard bow chock. After the chain hook is in, I let out about 30 feet of the nylon line, and cleat that to a heavy Herreshoff deck cleat near the bow. Then let out more anchor chain until the chain is visibly longer than the snubber line, so it hangs free with no strain. The strain is all on the nylon braided line. This has worked for years with no problems. Note that Yale Brait is VERY stretchy - that is important.

Posted by: acornscaptain | April 12, 2016 7:21 PM    Report this comment

HI All

My wife and I recently finished a 25 year circumnavigation on board our 37 Valiant Esprit, 20,000 lbs. We anchored hundreds of times, deep, shallow, rolly, smooth, muddy, rocky sandy, etc.. We would alternate anchors are required, 45 CQR or 42 Bruce and 200 ft 3/8 chain. I fabricated a chain grabber. All S/S with 2 bent over fingers that grabbed both sides of a chain link, with gap between for the next link. From there it was always a single 1/2 inch braided all nylon snubber line, over the bow roller and to a deck cleat. estimated overall length, 16 ft. We never had a breakage. Usually changed the line every couple of years... Worked for us.

Posted by: Tom Halfmoon | February 2, 2016 1:58 PM    Report this comment

I live on a 44 ton, George Buehler designed RPH trawler, 50' long by about 14.4' abeam, draft just under 5'. I have a 88 kg Roca anchor that is connected to the boat with 12 mm chain (sorry, have to go metric from now on) chain 130 m long. My FIRST snubber was a 16 mm maybe 6 meter long commercially purchased snubber that probably was NOT all nylon. I used that my first year and it was scary how thin it got. It was connected to an eye ring welded about 50 cm above the water line on the bow.
My second and third year used a nylon polyester line, 18 mm in diameter 10 meters long connected to the same point. The Claw that is used was a 316 ss 18 mm shackle with two "ears" 12.5 mm apart with a 90 degree bend in them welded to the rounded side of the shackle. This way, the load was even on boat sides of the link. Still got thin, to thin for my liking.

Last year, went with w 8x22mm nylon line, 20 meters long with the same claw chain hook. I run the line thru the eye located just above the waterline to the anchor claw/Chain and tie it off at the bow. This arrangement allows me to put out different snubber lengths as situations dictate.

I deploy a short amount of line when anchoring in shallow water, more in deeper water. The idea is that the claw is about 1 meter off the bottom when there is a 10-15 knot wind. With the line thru the loop at the waterline, the line still pulls relatively straight thereby increasing the effectiveness of the anchor. This year, had two experiences anchoring in 8 to 9 meters of water with gusts up to 40 knots, sustained 30+. In these case, I put out about 17 meters of the snubber and of course, put out more chain. After that first 8 hours, I was convinced I had done the right thing and the anxiety level went down. Survived both blows without a problem. The snubber never came off, and did not have any abrupt boat movements. Retrieving the anchor after both events was a PITA as it had dug in so deep that both required me to use the windlass to pull it our "backwards." But that was expected and I had planned on that.
Lee
MV Leeze
Izmir, Turkey

Posted by: LeeZe | January 29, 2016 3:04 AM    Report this comment

I use a chain hook with a 5/8" nylon 3-strand line every time to snub my anchor chain. I have a Jeanneau 43DS (25000 lb) with a 44 lb Lewmar Delta (main anchor) on 5/16" G43 chain. In difficult conditions, I will set another snubber, with the exact same setup, just aft of the first one, but not with the same tension - i.e., the second one will not take up any strain until the first one is farily well loaded. I have yet another snubber available, if necessary. I usually let out about 20 ft of snubber, but have about 40 feet available, if necessary

We used this method to anchor on the west coast of Scotland, one time in force 6 conditions, and it has worked quite well. I have never had a problem with the chain hooks, which are a standard load-tested 2-ton rated item. It is easy and cheap to replace at the first sign of problems. They drop off the chain as it is being retrieved and are easy to set and stow. I have also used them for a dual anchor situation with a second anchor(Bruce).

Posted by: rxc | January 28, 2016 9:10 AM    Report this comment

I have a Mainecat 41 catamaran with a bowsprit. The stays for the bowsprit are attached at the bows just above the waterline. I reinforced this area and added a second padeye with a block for the bridle on both sides. The bridle lines run through these blocks vertically to a deck level horn cleat. With the padeye low, about 4 ft. below the deck, you are able to veer less chain to achieve the desired scope. EG, 6 to 1 scope x 4 ft equals 24 ft. less rode. The extra 4 ft. gives a bit more line to stretch. I use 3/8" nylon for the stretch, and with the block the isn't any chafe point. An added benefit to being low is in current vs wind situations when the boat moves over the anchor, the chain doesn't drag against the bowsprit stays.
Steve Dashew addresses the benefits of small size bridle lines in one of his books.

Posted by: Andy Catsailor | January 28, 2016 8:05 AM    Report this comment

Great post that really introduces some innovative thinking! We sail and anchor our 38' 16,000lb sloop extensively around the rocky unforgiving lee shore and bays of Northern California where wind gusts are often extreme, and the ever changing currents and tides are unusually powerful (while at anchor recently, we experienced 45-55 knot wind gusts that corresponded with 'King' tides in the SF Bay and elsewhere on the Coast). As such, we use an all chain rode and always deploy our 25' bridle snubber of 7/8" 3-strand Nylon to absorb the frequently strong shock loads. We use a stainless steel Mantus hook and it has never fallen off or shown signs wear to itself or the chain, nor has our 45lb Rocna ever dragged (knock-on-wood) . We unsuccessfully tried several other snubber attachment techniques that fell far short including:
1) A simple hardware store 'eye grab' chain hook that always fell off the chain in the shifting winds and currents.
2) A 'claw' type chain hook that quickly bent open under the strain and wore the galvanized layer of the chain link.
3) A soft shackle loop but found that our 3/8" chain would abrade right through the outer cover layer and even cut into the inner elements within a few hours of being exposed to rough seas and winds.

Posted by: CA Dude | January 27, 2016 11:26 PM    Report this comment

We use dual 5/8" three-strand nylon snubbers, tied to the chain with rolling hitches and attached to bow cleats. The lines are 40' each, and we usually deploy about 30' in a bridle.

Our boat is a Sabre 38. Displacement 17,000 lbs. Fin keel and spade rudder with partial skeg.

Posted by: jazer | January 27, 2016 10:50 PM    Report this comment

On 46' Bright Water, we added a waterline bow eye that holds our 1/2" x 20' nylon double-braid snubber. Works perfectly and shortens our required scope. PS won't let me link to the blog post with pictures and more tech info.

I'm not a fan of the long snubber description in the article. Relative motion creates chafe.

Posted by: Capt. Phil | January 27, 2016 12:56 PM    Report this comment

We installed a waterline bow eye and use a 1/2" nylon snubber on 46' Bright Water. It saves unnecessary scope, quiets the anchor chain, and softens the jerk as the chain comes tight. Also, the snubber line is mostly underwater - lubricated and cooled. Works perfectly, including 25-35 all day, with gusts to 60.

Lots of pictures and discussion on our wordpress blog about sv brightwater than ps won't let us post a link to.

I'm suspicious of the method described in the article. A rope will chafe itself to death from internal movement. Running the line over fixed slides may saw right through it (another reason we installed the bow eye - keep the tensioned line off the gunwales and anchor roller).

Posted by: Capt. Phil | January 27, 2016 12:52 PM    Report this comment

I'm a US sailing Instructor and we teach our students in our Coastal Passage Making Classes to us a snubber every time they set an anchor by tying rolling hitch to the chain by using any of the available dock lines. I do the same on my 52' Jenneau Sun Odyssey.

Posted by: Tp3953 | January 27, 2016 12:06 PM    Report this comment

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