The sailboat block (commonly referred to as a pulley) is used to turn a line or wire as well as to facilitate a purchase.

The parts of a block, in simple terms, consist of the following:

  • a sheave for the line to run on
  • a sheave pin or axle for the sheave to spin on
  • a strap or a shell (depending on design) which provides the structure between the sheave pin and the attachment point. A shell acts as both strap and cheek.
  • Cheeks to house the strap and protect it from snags
  • an eye, hook, fork, shackle, strop or loop to attach the block to something

Another term that you’ll need to be acquainted with but not all blocks are equipped with, is Becket – an attachment for the end of a line to be affixed to; typically for a multiple part purchase system. There are yet even more fun parts of a block that aren’t as important for the layman like: crown, face, breech, swallow, tail, Tally Plate, score, and I’m sure I’m missing some. I just wanted to show off :-0)

Selden Plain Bearing Cruising Block
Selden Plain Bearing


As with most things in the sailboat parts world, things end up more confusing than clear once we actually get into it. For this reason alone many boaters trust those decisions to industry experts, such as riggers. Replacing a sailboat block unfortunately is no exception. When talking about modern day cruising or racing boats (anything not made of wood), there are many block manufacturers and model options available on the market. This can lead to the boat owner ending up needing to make more decisions than he or she was perhaps prepared for. Before embarking on the seemingly simple task of choosing blocks, allow The Rigging Company to shed some light on how we go about selecting the right block for the job…

First let’s start with a list of popular manufacturers and go from there. In terms of brands: AntalAllen, Ronstan, HarkenSchaeferLewmarKarver and Selden are some of the popular options available to choose from. Here is where the easy part ends and the confusion begins. Before you can figure out what type of block you’ll need, you still need to figure which model you like/want/need. Each one of these manufacturers will offer various design choices with even more jargon to add to your list: Carbo, ESP, Black Magic, Series 5, Series 7, OPF, Stainless, Classic, Looper, Orbit, Synchros, HTX, Core, Plain Bearing, Low load, Ball Bearing, High load; and on, and on, and on…

…Then, after that you’ll have yet even more decisions to make, like which size: 40mm, 45mm, 57mm, 60mm and so on. The final decision will be, what type… is it a double, triple, single, becket, snatch, cheek, foot, fiddle, ratchet, or any combination thereof…

…and when you’re all done figuring it out you may find yourself going home with a 57mm Harken Carbo Becket Fiddle Ratchet Cam….Block.

Confused yet? :-P

ROnstan Orbit
Ronstan Ball Bearing

Lets see if we can’t clear this up a bit…

WHICH MANUFACTURER: Of all of the brands listed above you will find that they all have something to offer that is worthwhile, some more than others. So this part of it many times can be narrowed down to what matches the already existing stuff on your boat, which brand you’ve heard good things about, or simply who offers just the right look for what you want. If you’re still not sure, a good place to start is the two brands that are sold the most here at our shop:  Schaefer and Harken. Schaefer is typically our first choice for the dedicated classic looking cruiser, and Harken is typically our ‘go to’ for the more modern looking racer-cruiser. As long as you take the time to size a block properly for its use, any new block that you want to equip your boat with will surely offer you years of trouble free service. Simple as that; you really can’t go terribly wrong in terms of which manufacturer you pick.

ALLEN Snatch Block
Allen Snatch Block

WHICH MODEL: Now we get into a bit more detail and this is where you’ll have to narrow it down based on what type of boat you have and what your budget might be. To keep this short, we’ll talk about what The Rigging Company (TRC) is always looking for in a good block. When choosing non-metal bearings look for Torlon or Delrin ball bearings. For UV resistance, we recommend choosing a black colored bearing over white, if there is a choice.  For the same reason we always prefer a black color if choosing a non-metal, composite sheave.

Torlon is the premium choice when it comes to roller bearing material.

The staff at TRC will tend to lean towards metal sheaves and cheeks, when available, for block longevity. If the block’s sheave pins are removable and the block can be disassembled and serviced, this is a big plus in our book. Also, it’s worth mentioning that we prefer blocks with forged shackles instead of stamped shackles. Having said that, other than the bit about white plastic ball bearings and white sheaves, none of these parts and what they’re made of are hard lines to our decision making, as much more goes into it.

BALL BEARING or PLAIN BEARING that is the question: Of course we always prefer roller bearings, right? Not always, as it turns out you don’t always need the rip roaring action of ball bearings, particularly in applications where the block isn’t especially free running, but under a lot of tension for long periods, like a boom topping lift or cascading backstay. Roller bearing blocks like to move and don’t particularly favor being under static loads for long periods of time. This can cause flat spots in the bearing, causing the block to not operate properly. If nothing else, ball bearings can start to become a noise nuisance when the boat and its rigging experiences very slight vibrations, causing a harmonic effect. Those of you that have heard that sound at anchor know what I’m talking about, it’s likely the ball bearing topping lift block hanging above your boom. Although we at TRC use and recommend mostly roller bearing blocks, keep in mind, less moving parts make for less maintenance.

Schaefer Block
Schaefer Plain Bearing

SIZE and TYPE: These last criteria, likely the most critical, are perhaps also the easiest. Deciding the type or style of block is simply a matter of what is required, e.g. 2 sheaves, 1 sheave and a dead end (Becket), etc…  Once that has been figured out we’re down to size. Typically the manufacturer categorizes their sizing using sheave size. Some manufacturers will use metric sizing such as 60 mm and some may use imperial terms like 2-3/8″. You will find that in most cases this sizing relates to the recommended line diameters, as well as load capacity. Paying attention to these last two details is the most crucial component to choosing the right block. This information should be listed on the product packaging or online specifications.

OH! Perhaps one other final consideration in the type or style category is: does the sheave need to ratchet or maybe support a metal wire?

Lewmar Ball Bearing Block
Lewmar Ball Bearing Block
KArver Ball bearing block
Karver Ball Bearing Block
Antal soft attach looper block
Antal Ball Bearing

Do youhave any additional thoughts? Tell us what you think. What is your favorite block and why? We’d love to hear from you!

4 thoughts on “Blocks

  1. You are missing the brand Allen from your list of block manufacturers, the picture of the Holt snatch block is a copy of the Allen one which we first designed and manufactured. Our products can be found on dinghies and small keel boats throughout the world and are used by National, European, World and Olympic champions. Success so far this year, International Dragon Worlds in Perth, Western Australia.

    1. Thank you Graham for noticing. You know I am embarrassed to say that perhaps we didn’t account for this split up when we wrote the article. It’s been republished at least once since the original. I don’t even see that snatch block that on their site anymore. So it is just an Allen Snatch Block now? Part #A4475, right? I will update the link in the article.

      Again thank you for noticing, I am sure we would noticed when we updated the article, but perhaps not.


      1. No Worries, we split over 10 years ago due to Holt’s relationship with Nautos. Allen were always the manufacturer of the products and we continue to do so with ever greater success. We sponsor a number of Olympic teams to ensure our products are always up to scratch. We also supply the worlds leading dinghy brands. We have also just started fitting out the Petticrow International Dragon last Autumn (Fall) which has already culminated in a World Championship in Perth, Australia, in January. We will also be fitting out the new Etchells being built in Cowes in the coming months. To cut a long story short, if you have been using Harken’s Carbo Magic range, you may well want to have a closer look at our Dynamic range, both in quality and price.

        If you are interested in any of our products, please don’t hesitate to give me a call or send an email, I’d be happy to help.

        Best Regards

        Graham Adams
        +44 (0) 1621 773715
        +44 (0) 7736 132880
        Cert No. 11184-QMS-001

        2019 Catalogue

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