Tech Team - Soft-Attach Blocks

Shackle vs. Soft-Attach


In this article:

  • Pros and cons of shackle vs. soft-attachment options
  • Traditional forms of block attachment
  • The advantages of new Dyneema® rope technology
  • Common pit falls with soft-attach installation and how to do it right

Shackles have been used by sailors for many years to attach blocks to boats. They are not only reliable and strong, but are also excellent indicators as to when a block might need replacing. Deformation or distortion on the shackle is a good warning sign that the block is working at its maximum load capacity and could be due for replacement or service. Distorted shackles help ensure we change our blocks before breakages occur which are, let's face it, usually right in the middle of a race when we don't want them to fail!

So why deviate from the norm when a shackle works perfectly well?

With today's advances in rope and materials technology, we are seeing an increased demand for lighter, stronger, go-fast equipment, and an evolving trend toward soft-rope attachments-from dinghy and weekend sailors, to elite British Sailing Team athletes and Olympic hopefuls, to Volvo Ocean Race and Maxi sailors.

Is Dyneema® rope strong enough?

'Rope?' you ask. 'How can it be strong enough to hold the high loads on my blocks?' Well, in fact, when compared on a weight basis, Dyneema is 15 times stronger than steel wire. That's pretty strong! On top of that, it is lighter than a steel shackle and buoyant enough to float in water.

Chafe is another consideration. Rope is kinder both to your boat and to your hardware. In addition, soft-attach options allow better articulation than a shackle. This means the load being pulled through your block will be at an optimal angle, reducing the risk of breakage, and space taken up on deck.

Why isn't everyone using soft-attachments?

For all their benefits, there is a lack of understanding of the advantages of rope attachments among sailors, as well as the fear of trying something new. In addition, wear and chafe on rope attachments is easier to spot and requires regular inspection more often than a shackle.

Another common reason why people have had problems with soft-attach solutions is that they have experienced block breakages. These breakages in the dinghy range are most often due to blocks being tied incorrectly.

Therefore, it is essential that the installation of your soft-attachment is correct for your specific fitting and not just simply "tied" on. Find information on installation instructions on our website:
Carbo T2 blocks (tie/splice)
Carbo T2 loop blocks
Black Magic loop blocks

In what circumstances should you use either a shackle or a soft-attachment?

The main advice I can give here is that soft-attachments require smooth radius attachment points; sharp or rugged edges, like toe rails, can cause wear/weak points to form in the rope. If edges are rough, then a shackle would be more appropriate, if the surface has a smooth radius, then you can us a lighter soft-attachment.

I would use a soft-attachment when greater articulation is required and weight is a consideration.

How to tie your soft-attach block correctly

Block failure in the soft-attach range is mainly due to incorrectly installed soft-attachments. This can cause frustration when sailors don't know what's going wrong. To combat this I am going to show you the right, and the wrong way to tie on your soft-attach blocks.

See images below.

Dr Harken correctly tying soft-attachments_750px

Dr Harken correctly tying soft-attachments_2_750px

Dr Harken correctly tying soft-attachments_3_750px


Soft-attachment explanation: Watch this video from back in the day when we first launched the Ti-Lite generation of blocks. Andy Ash-Vie, MD of Harken UK walks us through the various benefits and uses for soft-attachment blocks.

When it comes to choosing between shackles and soft-attachments, the choice is really as individual as each boat and sailor. It's clear there is a shift toward using soft-attachment options because of the performance benefits discussed above. The key is to ensure the installation of these new attachment options are understood and applied correctly!

How do you install your soft-attachment blocks?

Harken makes it easy with simple-to-follow installation guides, downloadable from our website!

Click here for T2 soft-attachment installation instructions

So why are soft-attachments so special?

  • Light and strong alternatives to shackles
  • Simple to follow installation instructions on our website
  • On-hand technical support for you when you need it
  • Easier to identify chafe
  • Greater articulation for optimal load displacement
  • Kinder to your boat and your hardware

Soft attachments are ideal for:

  • Traveler controls
  • Mainsheets and vangs
  • Cascades
  • Bridles
  • Other systems requiring lightweight blocks

Things to watch out for:

  • Installation: Read the instructions and tie them properly. If you're not sure, call the Harken Tech team. They will happily walk you through it.
  • Chafe: Check your soft-attachments regularly for chafe and wear.
  • Maintenance: Wash regularly with fresh water.

Until next time…

Watched the video, read the instructions, but still have questions? Feel free to contact the Tech Team at any time via the details below:

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