Please select your home edition
Edition app (top)

Cousin Trestec Constrictor - A Textile Rope Clutch!?

by Kerri Robson 18 Feb 09:00 UTC
Cousin Trestec Constrictor - A Textile Rope Clutch © Cousin Trestec

At some point in our lives, we have all experienced the vice-like grip of the 'Chinese finger trap'; when pulled, the cylindrical, woven braid is designed to contract and constrain the finger. It is this mechanism that forms the simple premise behind French brand Cousin Trestec's rope 'constrictor'.

Cousin Trestec a key player in the manufacture of innovative marine ropes and braided textiles - first designed the constrictor a number of years ago. The product revolutionised the French offshore racing scene, and has gained in popularity ever since, with more and more racing and cruising sailors choosing the lightweight, high load constrictor over more traditional rope clutch designs.

The patented constrictor design which has previously won a DAME award - is simple yet effective. Working as a fibre-on-fibre rope clutch, the system utilises a hollow, braided, textile sock that - in one direction - enables rope to run freely, but - in the opposite direction - immediately locks the rope into place.

In order to lock the line into place, the constrictor uses friction: under load, the sock instantly clings to the rope, stopping it in its tracks. Also, unlike traditional cam-based clutches, the higher the load, the greater the hold!

Copyright Cousin Trestec

Releasing the rope is also uncomplicated: simply pull on the control line to retract the sock and it will release hold on the rope. The control line can also remain pinned back, allowing the rope to run freely both ways. There is also potential for the control line to be extended, allowing the rope to be released remotely if desired. This opens up some interesting opportunities for using them as halyard locks on small boats!

But what are the advantages of using a textile constrictor over a metal rope clutch?

A significant benefit is that fibre-on-fibre interaction is not as harsh as metal on fibre. Whilst some traditional rope clutches crush the rope between metal jaws, the soft braid on soft braid ensures there is no abrasion on the rope - and as a result the Cousin Constrictor is kinder to your running rigging (and therefore your wallet!). The braided sock also ensures a balanced distribution of the grip. The result? Less wear and tear, plus lower maintenance costs.

Another advantage is weight: the Cousin Constrictor is three times lighter than a conventional metal clutch, increasing performance and perfectly aligning with's motto of faster, lighter, safer sailing.

Copyright Cousin Trestec

In addition, the Cousin Trestec Constrictor is twice as strong as a traditional rope clutch; the line can be taken off the winch without worries of slippage, with the break strength of the textile clutch equalling the break strength of the rope it is retaining (the only limit being the strength of the surface the clutch is mounted on!). The line can also be released under any load without the assistance of a winch, which can be deemed as safer in critical situations.

Benefitting from easy installation and maintenance, the Cousin Constrictor is also mountable anywhere although, due to its length, it does require more space on deck than some traditional rope clutches. However, the lack of moving metal parts ensures corrosion is low and, if damage occurs, the sock can be replaced as an individual part.

Ready to make the move towards a textile clutch? The unique constrictor comprises an aluminium housing (which acts as the mountable anchor base), a textile sock made of aramid fibres, a 'nut and olive' coupling system to fix the sock in the housing, a shock cord and a Dyneema® control line.

Explore the Cousin Trestec Constrictor range at, or contact using the running rigging enquiry form.

Related Articles

Reducing Weight Aloft with Composite Backstays
Simple replacement offerring superior performance over wire Reducing weight aloft is one of the most cost effective ways of increasing your boat speed and performance: every kilogram you take out of the rig is roughly equivalent to 4kg added to the bottom of your keel. Posted on 22 Apr
PROtect Tapes take on regatta plastic pollution
Biodegradable and compostable hull stickers available Experts at creating products designed to tackle chafing, abrasion, scratches, damages, ageing, and wear, PROtect Tapes have now honed their unique technical film know-how to create biodegradable and compostable bow and hull stickers Posted on 17 Apr
Fresh In - Tiller Extensions
From three big players: Spinlock, Harken and Ronstan We are excited to now introduce six ranges of tiller extensions on, from three big players: Spinlock, Harken and Ronstan. Posted on 15 Apr
Dyneema Braided Cover
The latest addition to your tool kit Dyneema® is the strongest fibre in the world. Ten times stronger than steel, and seven to ten times lighter than a steel wire of equivalent size, Dyneema® is one of the most durable and sought-after materials on the sailing market. Posted on 8 Apr
Robline Rope: Dinghy Ranges
Extensive range specifically developed for dinghies and small sport boats Robline has an extensive range of lines specifically developed for dinghies and small sport boats. In this post, we discuss the different types of dinghy lines and their recommended applications. Posted on 3 Apr
Bjarne Lorenzen talks Top-Down Furling
Andy Rice interviews Bjarne Lorenzen of sailmaker Doyle O'leu In part three of this series, Bjarne Lorenzen of sailmaker Doyle O'leu explains the benefits of top-down furling, one of the big developments of the past decade which has trickled down to the cruising scene from the Volvo Ocean Race. Posted on 29 Mar
Lash Thimbles
What are they, and how do I use them? Lash thimble, ferrule, rope thimble, bobbin or low friction ring... whatever you call them, there's no denying they are the perfect (low cost!) solution for a multitude of applications. Posted on 25 Mar
How do I rig the bobstay of my Trogear bowsprit?
Reaping the benefits of a retrofitted removable bowsprit The bobstay is connected to the tip of the bowsprit and routed to a u-bolt, which is attached on the bow. Assuming the sails are deployed and the bowsprit is horizontal, the bobstay should achieve an angle of 45 degrees or more. Posted on 20 Mar
Ronstan Core Block Range
Significant time and effort invested in developing this range Ronstan invested significant time and effort in developing this functional and stylish range, for keelboat sailors. Posted on 15 Mar
Introducing the LOOP Products E-Furler
Gennaker furling at the touch of a button Launched at Dusseldorf Boatshow 2017, the LOOP® Products E-Furler 1500 brings push-button technology, safety and comfort to sportsboat gennaker furling. Posted on 11 Mar app (top)