Please select your home edition
Upffront 2020 Foredeck Club SW LEADERBOARD

How to change the cover on a Cousin Constrictor

by Aleix Escorsell 30 Oct 2019 02:00 PDT
Cousin Trestec Constrictor - A Textile Rope Clutch © Berschi

Created as a lightweight alternative to traditional metal clutches, the Cousin Constrictor© is a great bit of kit for reliably holding rope under load with great longevity when properly maintained.

Rope innovators, Cousin are at the cutting edge of marine rope and textile technology and have been able to revolutionise the French racing scene with great products such as the Cousin Constrictor©.

Cousin claim that their Constrictor is three times lighter than metal alternatives and twice as powerful. Coupled with the fact that the Cousin Constrictor© does not damage the line in any way makes it a great alternative to traditional rope clutches for a variety of boats and yachts.

This blog will help owners of the Constrictor, and those looking to purchase this versatile textile rope clutch, learn more on how to properly maintain and increase the lifespan of the Constrictor. With a step by step guide, and examples provided by Cousin, you will be able to confidently look after your Constrictor and change the cover if needed.

Looking after your Cousin Constrictor©

The sleeve is made of a high tenacity black technora, which is extremely sun and heat resistant, and the casing is made of an anodized aerospace-grade aluminium housing.

All of this makes the Constrictor a reliable and extremely durable clutch. However, as with any textile product, usage does wear on the sleeve over time. Cousin recommends a few tips and tricks to improve the lifespan of your Constrictor:

  • Avoid over-loading where possible. The Constrictor can hold as much as the rope can, and grip actually increases with load! That said, high load over time will eventually wear the Constrictor and can lead to damage.
  • Regularly wash the Constrictor© with fresh water. Harmful compounds such as sand, sea water, sharp equipment and chemicals can do damage to the Constrictor. Washing with fresh water will help improve longevity.
  • In winter, uninstall the Constrictor or use a cover when not in use.
  • Avoid cleaning the Constrictor with high pressure cleaners that may introduce abrasive elements into the fibres.

Even with excellent maintenance, wear and tear may lead you to require a replacement sock, but how do you know when to change?

Here are a few key things to look out for:

  • Is there any obvious damage such as cuts or tearing?
  • If you can see the rope beneath the sock, it may be time to change your cover.
  • Is the cover fraying or fluffing up?
  • If the pattern on the cover is no longer consistent or you can see strands that have detached from the main sock, this could be a sign that your cover needs to be replaced.

Particular attention should be paid to the junction between the braided sock and the cone fitting. This is where the sock exits the aluminium fitting and the most likely point of significant damage.

If you do see damage to the cover, it's important to assess the damage and change it if necessary. Below is a step by step guide on how to change the cover.

Changing the cover of your Cousin Constrictor

Step 1 - Remove the Cousin Constrictor© from your boat

Changing the cover while the Constrictor is attached to the boat may cause damage to the Constrictor and the boat. Therefore, we recommend removing it before you begin the process.

Step 2 - Insert the metal punch (see note below on this custom tool) into the same hole that the cover comes out of, pushing the cover aside as you do so.

Step 3 - Bash the top of the punch with a hammer to release the titanium ring. It should come out of the bottom.

Step 4 - Remove the titanium ring and the cover from the housing and set them aside.

Step 5 - Insert the new cover into the housing and pull it through to the other side.

Step 6 - Carefully splay apart the fibres to allow the titanium ring to fit comfortably inside the end of the cover, then insert the titanium ring into the end of the cover, thinner end first.

It's important to ensure that the fibres are evenly spread around the titanium ring to ensure that the load is spread equally throughout the cover.

Step 7 - Ensuring that the ring stays encased in the cover, Pull the cover back through the housing and push the ring in to the hole. N.B. You should be able to see the cover all the way around the ring.

Step 8 - Using the punch and a hammer, punch the ring in to the housing. It should now be jammed in and unable to move and you should still be able to see the cover all the way around the edge of the ring. Pull on the end of the cover to ensure it is secure.

Ensure that you test your Constrictor with a light load before you sail.

With this guide you should be able to get the most out of your Cousin Constrictor©. Don't forget to regularly check your Constrictor for cuts and tears, regularly wash it with fresh water and avoid overloading it.


In order to change the cover yourself, you will need a punch (pictured below), specifically designed for this operation. The tool needs to be two thicknesses, the thin end needs to be able to fit inside the aluminium ring and the thick end needs to have the same diameter as the OD of the titanium ring.

While Cousin do not currently sell this tool, we recommend that you contact them regardless, as they are considering releasing them as a product in the future. If not, any decent metal shop would be able to craft the correct tool and can supply the dimensions.

It's important to stress that this tool is critical because it ensures that the aluminium housing is not damaged, and the structural integrity of the clutch is not compromised during the sock replacement process.

If you do not feel confident in doing it yourself, take your Constrictor to a local rigger for assistance.

If you have any questions about the specifications of the Cousin Constrictor©, or to buy a new cover, visit or alternatively use the contact form.

Related Articles

Sailboat Load Data
Optimising hardware and rigging design Find out just how far we still have to go in terms of understanding yacht mast and rigging loads, and why they are so important to the specification of sailing hardware and rigging systems. Posted on 30 Jul
Replacing Karver's Furler Quick Release Spring Kit
Captive pins are almost universal on furling drums and swivels The quick release mechanisms rely on small springs which can get damaged and require replacement. This article will outline the evolution of the Karver captive pin systems and help you identify the correct replacement spring kit for your Karver furler. Posted on 25 Jul
Morf Block merges into Morfrac Systems speaks to the inventor, Nicolas Goldenberg At we're big fans of the Morf Block. The lightweight, 3D-printed block started as a DIY kit and has expanded into two ranges: high performance and high load. Posted on 8 Jul
The Low-Down on High-Load Dinghy Blocks
Allen, Harken, Ronstan and Morf compared At we love looking at the data and comparing products to gain insight. In this blog we look at the rapidly evolving world of high-load dinghy blocks and compare leading products on the market from Allen Brothers, Harken, Ronstan and Morf. Posted on 26 Jun
Spinlock's XTX available at
The latest innovation in rope holding Widely known as experts in rope holding, Spinlock is the go-to solution for many sailors when it comes to clutches and jammers. We've been looking forward to the launch of their new product, the XTX Clutch, ever since we got our first look at METS 2019. Posted on 19 Jun
Ubi Maior X3M Flight Blocks
The compact high flyer reviewed by Where does the Ubi Maior X3M Flight range sit relative to other blocks? Posted on 12 Jun
Allen Brothers overview from
Dedicated to manufacturing excellence We are pleased to introduce the Allen Brothers 20mm and 30mm Dynamic Block ranges on the website and decided to take the opportunity to have an in-depth look at this fascinating UK manufacturer of performance dinghy hardware. Posted on 5 Jun
nke - Finding Their True Course look at these high quality, precision navigation instruments nke is a specialist marine electronics manufacturer which has built a reputation, over 35 years, for high quality, precision navigation instruments for sailing yachts. Profiling companies like this is part of's raison d'être. Posted on 28 May
Ewincher - An alternative to electric winches?
A power-assisted winch handle requires no installation Electrification of winches can be a great benefit; reducing the strength and manpower needed on your boat and allowing many to sail short-handed or continue sailing longer in life. Is the Ewincher a viable, cost-effective alternative? Posted on 11 May
Extend your reach with Ronstan
The Battlestick is the self-professed 'next generation of sailing weaponry' Ronstan is an Australian born company who has developed hardware for both small and big boats since 1953. In this article we will look at their extensive range of tiller extensions which have become a brand in their own right: the Ronstan Battlestick. Posted on 30 Apr
Upffront 2020 Foredeck Club SW FOOTER