Deck Gear: Low-friction Rings

Graham Snook looks at where you can and can’t replace regular blocks with these handy bits of gear
Author:
Publish date:
The adjustable genoa lead shown here represents one of the most popular uses of low-friction rings

The adjustable genoa lead shown here represents one of the most popular uses of low-friction rings

You may be surprised to learn there’s nothing new about the half-doughnut-half-sheave-shaped bits of aluminum known as low-friction rings. In fact, low-friction rings, in one form or another, go back thousands of years in the form of the traditional lignum vitae wooden single deadeye. They have more recently been brought up to date for the simple reasons that they’re cheap, lightweight— and they work.

If you haven’t come across a low-friction ring, or have discounted them as race-tech gadgetry, think again. Made of lightweight hard-anodized aluminum and available for line sizes from 1/8in to 1in (with external diameters from 1/2in upward), they can, in fact, serve a multitude of uses.

Around the outside is a rounded groove much like that of a traditional sheave. However, in the case of a low-friction ring, the running line feeds through the hole in the middle, which has been rounded in all directions to allow the line (or lines) to pass through as smoothly as possible. The outside groove, on the other hand, is used to secure the ring at the end of another piece of line with a loop.

Simple enough. However, this bit of kit can be used for everything from fairleads and through-deck fittings to snatch and foot blocks, thanks in part to the fact that, unlike traditional blocks, once in position they allow a line to exit in any direction.

Rings can be especially tempting for the cost-conscious sailor, since a comparable block can cost hundreds of dollars. However, in answer to the question, “Are they as efficient?” the answer is, no. Which means that while they can be used to replace blocks in many applications, they can’t be used in all of them.

That said, rings can be used with a wide range of lines material, and given their inherent strength when used with strong-as-steel UHMWPE materials like Spectra and Dyneema, they can be incredibly robust for their size. Better still, unlike a conventional block, which will disintegrate upon reaching break load, a ring supported by a piece of line will simply deform.

To get an idea of what kinds of loads we’re talking about here, figure a 3in/75mm block for a 10mm line may weigh around 7-14 oz. and have a SWL (safe working load) of 1,100-1,900lb. A comparative low-friction ring will weigh less than half an ounce and have an SWL of 3,500lb.

Again, though, while low-friction rings can replace blocks in many situations, there’s a caveat: doing so will increase the friction within the system. These are, after all, “low” friction, not “no” friction rings we’re talking about here.

Also, unlike a block, where the amount of friction will be constant and fairly minimal no matter the entry and exit angle of the line or the type of cordage used or the load it’s under, the same cannot be said for low friction rings. Adjust any of the above variables and the friction between the line and a ring will also change.

As an example, take a block, pass some 1/4in Dyneema through under minimal load and deflect 30 degrees. The increase in friction will be barely noticeable. By contrast, a 1/2in line with a hard-wearing high-friction outer cover of Aramid/Technora passing through a ring and loaded up at 1,000lb or more will increase the coefficient of friction dramatically. Passing the line through the ring under load will also generate heat.

With this in mind, rings work especially well in settings where a line doesn’t move a lot: in other words, static or semi-static applications. They are also good when used to deflect loads less than 90 degrees. For example, as, say, headsail fairleads they can work wonders.

This cluster of low-friction rings takes up far less space than an equal number of blocks

This cluster of low-friction rings takes up far less space than an equal number of blocks

By contrast, they work less well as turning blocks where it’s necessary to reverse or deflect a line past 90 degrees, or when lots of line will be passing through. As Harken’s Andy Ash-Vie explains, “On high-line speed applications, like spinnaker sheets or mainsheets, the friction and heat can build up fast. It is harder on the trimmer and on the sheet itself.”

Along these same lines it’s also best to keep the number of rings in any purchase system to a minimum, since the friction buildup will be cumulative with every ring. Ash-Vie, for example, says he won’t use more than one at a time, preferring to use a pulley system to get the mechanical advantage from, say, a cascade purchase system. Others, however, are less concerned. The ultimate decision is up to you.

Finally, it’s always a good idea to consider what exactly it is you’re hoping to achieve by replacing a block, or blocks, with low-friction rings. Are you doing it just to save a little money or will there be a real benefit? This goes for cruisers and daysailers as well as hardcore racers. Which is not to say they don’t make sense on cruising boats. Weight savings, for example, may seem a moot point aboard a cruising boat. But try winching up a block-laden mainsail 60ft or more, and you’ll be happy to make things as light as you can get them.

What follows are some considerations to keep in mind when thinking about low-friction rings in a number of different applications.

A pair of low-friction deck organizers

A pair of low-friction deck organizers

Turning Blocks

While it might be tempting to try and save hundreds of dollars by spending $20 on a low-friction ring instead of a conventional block, doing so successfully depends on the size of your boat, the loads at work and the sailing you do. Because of their increased friction, rings don’t release smoothly, which means lines under load can “jump” when eased or trimmed.

Bottom line, with lines that are trimmed frequently under high load the best solution is still typically a conventional turning block. That said, if you’re a set-it-and-forget-type when flying a spinnaker, then the turning block could be replaced with rings attached to strong points (like cleats, toerails or padeyes) with a store-bought or homemade strop. Just keep in mind that potential friction buildup.

Mast Base Blocks

If the base of your mast is getting crowded with blocks, as is often the case with older boats in particular, replacing some of the lesser-used ones with rings is a great way to free up some extra space. Keep your good-old roller blocks for the main and spinnaker halyards. But if your genoa is on a furler, and you only raise and lower it at the start and end of the season, it might be a good candidate for a low-friction ring. Another good way to reduce the number of blocks is to run more than one reefing pennant from the boom back to the cockpit through a single ring, as you’ll only be using one of them at a time.

Deck Organizers

Where low-friction rings and fittings are truly in their element is deflecting semi-static lines (i.e., lines that don’t move a lot) under load. Low-friction deck organizers (close cousins to low-friction rings), for example, take up much less room than those with sheaves. You also don’t have to worry about them getting bunged up with salt.

Furling Lines

There is no doubt a low-friction ring works better than a seized or twisted block, and few blocks on board get as salt-encrusted as those used to guide headsail furling lines aft. Several rings attached to an equal number of stanchions will typically work well, especially when there is little load. Again, though, as the load on the furling line increases so will the friction on each ring. This will all add up, so the fewer rings the better.

Vangs and backstay systems

Low-friction rings can also be used successfully in a semi-static purchase systems like those found on vangs and adjustable backstays, where loads can be high but the movements/size of the adjustments is small. Rings lend themselves especially well to cascade purchase systems, in which the load is roughly halved with each ring pulling down on the ring directly above, with the static ends all attached to a single point. As the loads decrease, thinner line and smaller rings can be used to further decrease weight and increase savings.

Lazy Jacks

Using small rings with nice, thin lazy jack lines means less sail chafe than would result from using smaller, more expensive blocks. By running the lines through rings, the system will also be lighter and the airflow over the surface of the sail less disturbed.

In and out-Haulers

An area in which rings are especially popular is as barber haulers or other systems used to adjust headsail sheeting angles. Typically, a genoa sheet runs back to an adjustable genoa car on a track. Forward of the car, though, close to the clew, the sheet can also be run through a ring that is controlled from the cockpit and used to pull the clew closer to the boat’s centerline, narrowing the slot between the headsail and the main. An out-hauler, or barber hauler, does the opposite, pulling the sheet outboard to open up the slot when off the wind.

Genoa Sheet Twing

Sailors of older boats often cannot adjust the genoa sheet lead under load from the cockpit, since the pin in the genoa car has to be pulled up, and the genoa car physically moved along the track in order to do so. Of course, fully adjustable genoa cars can also be prohibitively expensive given the value of many older yachts; however, a much cheaper solution can be had using a ring as a downhaul in front of the car to bring the lead down closer to the deck. This will serve the same purpose as moving the genoa car forward, thereby tightening the leech and reducing twist—an especially handy tactic when going off the wind or when a furling headsail is reefed. To make the loads more manageable, friction rings can also be used to increase the mechanical advantage of the system on its way back to the safety of the cockpit

Reefing Lines

Friction is the enemy on any mainsail reefing system and if you want the most efficient single-line reefing system you’ll have to put your hand in your pocket and spend money on high-load blocks and sheaves with bearings. That said, you can also try going with a ring on the leech with little gain in friction. Be warned, though, if you have a single-line system don’t be tempted to replace the block at the luff, as a lot of line has to pass through at this point and shaking out a reef can become the devil’s work if you introduce more friction. Be happy that instead of buying four or six blocks you have, at least, halved the number. 

Resources

Antal Marine antal.it

Barton Marine bartonmarine.com

Colligo Marine colligomarine.com

Harken Inc. harken.com

Ronstan ronstan.us

Ropeye ropeye.com

Photos courtesy of Graham Snook

January 2021

Related

e60aa842-1c3c-41da-b0ba-dfd7678479e4

The New York Yacht Club Submits a Protocol Alteration with its America’s Cup Challenge

The New York Yacht Club (NYYC) has submitted a challenge for the 37th America’s Cup to the current Defender, the Royal New Zealand Yacht Squadron (RNZYS) in Auckland, New Zealand. The challenge was accompanied by a draft protocol for the regatta, which would see the Cup take ...read more

01-LEAD-CCA-Antarctica2-01

Cruising: Honoring Remarkable Ocean Voyages and Seamanship

The Cruising Club of America, an organization of about 1,300 offshore sailors, has been honoring remarkable ocean voyages and seamanship with an array of prestigious awards for nearly 100 years. The club’s highest honor, the Blue Water Medal, has recognized renowned and ...read more

2.4mR's racing at the 2018 Clagett Regatta-US Para Sailing Championships credit Clagett Regatta-Andes Visual

Host for 2021 U.S. Para Sailing Championships Announced

The 2021 U.S. Para Sailing Championships will be hosted by The Clagett Regatta at Sail Newport, in Newport, R.I. on August, 24-29, 2021, according to a joint announcement from the host and US Sailing. "We have had a very long working relationship with US Sailing and look forward ...read more

Reflections-photo-CMerwarth

Cruising: Reflections of an Old Salt

I am 90 years old, dwindling in mind and body and fear living too long. Twenty years have passed since I last weighed anchor. Still, when a Carolina blue sky is polka-dotted with billowing cumulus clouds and the wind blows fair, I sorely miss raising sail and setting forth. I ...read more

DSC_0145

Waterlines: Solo Sailing

In spite of the fact I came to the sport of sailing alone and untutored, in a boat I acquired on my own, I never really aspired to become a solo sailor. It just sort of happened. All these years later, I still never explicitly plan to sail anywhere alone. I’m always happy to ...read more

01a-DJI_0398

Racing The M32 Class

This year the M32 celebrates its 10th birthday. Swedish Olympic bronze medalist Göran Marström and Kåre Ljung designed the M32 in 2011 as the latest addition to an already impressive portfolio that includes the Tornado, M5 A-Class, M20 catamaran and the Extreme 40. Two years ...read more

01-LEAD-23274-Coastal-Oilskins-GSP

Know how: Cleats, Clutches and Jammers

Since the invention of rope, there has also been a need to belay or secure it. Every sailboat has rope on board so, unless you own a superyacht with captive reels or winches, you’re going to have to find a way to make it fast. (As a side note—and before you reach for your ...read more

9e4d8714-2a8e-4e79-b8f6-c9786aaec4d0

Antigua Sailing Week Announces Women’s Mentorship Program

In partnership with the Antigua and Barbuda Marine Association, Antigua Sailing Week is launching a mentorship program to encourage women and girls to join the sport of sailing. President of Antigua Sailing Week, Alison Sly-Adams says, “When we devised the program, we looked at ...read more