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Unlike all conventional clutches the Constrictor® system does not crush the rope between two metal surfaces. Instead, the loaded rope is held securely in a textile sock, itself attached to an anchor base. The rope runs freely through the sock in one direction, but is gripped instantly within the sock when running out in the opposite direction. This constrictor effect, patented by COUSIN Trestec, provides increasing holding power as the load increases.



The standard Constrictor® range provides 2x the holding power of conventional rope clutches, and custom solutions are available with holding power up to the break load of the rope!


At least 3x lighter than conventional rope clutches.

No Abrasion or Rupture:

The unique textile sock closes like an octopus on the line, providing effective load distribution and outstanding grip; a result of fibre-to-fibre contact that is far less aggressive than traditional metal cams.

Safely Release Under Load:

The line can quickly and easily be released under load without the need of a winch, simply by pulling the control lanyard. This can be an important safety consideration in situations where immediate release is required.

Remote Release System:

The Dyneema® control lanyard can be extended to provide remote release, making it ideal for applications such as mast-head mounted halyard to eliminate mast compression loads and halyard creep.

See the full Constrictor® range



Textile Sock:

  • Braid Orientation: COUSIN Trestec’s experience and expertise in rope manufacture has guided development of the critical braiding angle to maximise grip and minimise slippage.
  • Fibre Assembly: Extensive knowledge of fibres combined with laboratory and field testing has resulted in an optimal fibre balance and density for unmatched strength.
  • Treatment: A specialised surface treatment plays a critical role in extending the product life, boosting grip and reducing abrasion in stress areas.

Bi-conical Titanium Base:

Patented by Cousin, the textile sock element is locked in place between a titanium ring and the anchoring base. The unique conical geometry allows easy insertion of the rope, and ensures that the sock is perfectly integrated with the anchor base in supporting the applied load.

Opening System:

Pulling on the SK75 Dyneema® lanyard retracts the sock, relaxing the grip on the rope and allowing it to run freely in either direction. The lanyard can be fixed in the open position using the V-notch in the anchor base.


Constrictor Diagram

Product No Clutch Size Breaking Load (ุ rope) Weight I Width L Length
Kg lb g oz mm in mm in
CT306P001 Constrictor 6 (1/4”) 460(ุ5) / 760(Ø6) 1010(ุ3/16”) / 1670(Ø1/4”) 150 5.3 25 115 4 9/16”
CT308P001 Constrictor 8 (5/16”) 710(Ø5) / 1170(ุ6) 1560(ุ1/4”) / 2570(Ø5/16”) 155 5.4 25 115 4 9/16”
CT310P001 Constrictor 10 (3/8”) 1220(ุ8) / 2240(Ø10) 2680(Ø5/16”) / 4920(Ø3/8”) 160 4.6 25 115 4 9/16”
CT312P001 Constrictor 12 (1/2”) 1530(ุ10) / 2850(Ø12) 3360(ุ3/8”) / 6270(Ø1/2”) 330 11.6 36 1 3/8” 126 5”
CT314P001 Constrictor 14 (9/16”) 1830(ุ12) / 3770(Ø14) 4020(ุ1/2”) / 8290(Ø9/16”) 340 12.0 36 1 3/8” 126 5”

Product No Clutch Size H Height LOA E min E max ุ Screw
mm in mm in mm in mm in mm in
CT306P001 Constrictor 6 (1/4”) 45 4 1/2” 588 23 5/32” 70 2 3/4” 90 3 1/2” 8 5/16”
CT308P001 Constrictor 8 (5/16”) 45 4 1/2” 638 25 1/8” 70 2 3/4” 90 3 1/2” 8 5/16”
CT310P001 Constrictor 10 (3/8”) 45 4 1/2” 638 25 1/8” 70 2 3/4” 90 3 1/2” 8 5/16”
CT312P001 Constrictor 12 (1/2”) 58 787 31” 70 2 3/4” 90 3 1/2” 12 1/2”
CT314P001 Constrictor 14 (9/16”) 58 787 31” 70 2 3/4” 90 3 1/2” 12 1/2”


You will already find the Constrictor® solution in use on the top Maxi, Mini, Multi, IMOCA and AC72 teams. COUSIN Trestec have developed a trouble-free and ergonomic product that will please anyone looking for the New Generation in rope holding technology.

COUSIN Trestec

The manufacturer of the Constrictor® COUSIN Trestec is renowned for technical and professional competence in lines, ropes and fibre cables. COUSIN Trestec brings together the strength and knowledge of a industrial group for the service of its customers. The secret of their success? Unrivalled know-how, coupled with a wide and diversified range of high spec products supplied and supported through a worldwide network of agents and distributors.

Pittman Innovation Award


Constrictor® gives you the opportunity to completely redefine your deck plan. It offers high performance rope holding with an unrivalled level of integrated and aesthetically pleasing solutions – free from the clutter, bulk and obstruction of conventional rope clutches. Why have your clutches visible when they can be hidden under a low profile hood or partition!

Constrictor Integration


Custom Constrictor® solutions are available with holding power up to the break load of the rope, and ‘insert’ designs are possible for direct integration into hull or spars via lamination or other methods. Contact us to discuss your needs.

Custom Constrictor