A Quick Ropes QuickGuide to choosing sheets and halyards

Posted by Shane Gray on


Sometimes it can be difficult to size sheets and halyards from memory so we have prepared this quick guide to help you get it right. Diameters have been chosen using standard braid on braid polyester breaking loads. If you use Dyneema® or aramids you can usually reduce the diameters given here. Bear in mind the thickness of some ropes is chosen for ease of handling rather than breaking load so moving down a size when using stronger ropes is not always the best solution.


To use this guide find the size of your boat in the column on the left of the first table and read across to get the suggested diameters for sheets and halyards. We have also shown estimated sail areas for comparison. As an example we suggest a 10mm diameter main sheet for a 30-33 foot boat as shown below.


The second table gives some guideline lengths for sheets and halyards. Sizes are generous to allow for aft led halyards, however every boat is different and your boat may have a unique configuration so use this table with some caution.


We are compiling a database of exact lengths for common models so check for updates. Remember our pre-cut and spliced halyard and sheet packs can be exchanged within 30 days.


Rope sizes table



Years of experience have helped us to identify the most common sizes of sheets and halyards used on many yachts. We have distilled this knowledge into a new range of products supplied as cut and spliced lengths to suit a variety of boats.


Halyards are constructed using the finest 32-plait braid with a parallel fibre core so stretch is minimized to around 2% under 20% load. A mechanically spliced captive pin shackle or snap-shackle is also included.


Sheets use 24-plait braid on braid for smoothness and ease of handling.

Best of all large volumes keep the prices down so it works out cheaper than buying the same rope as a cut length and splicing it.



As a rough guide polyester braid has approximate breaking loads as follows:


6 mm  850 Kg
8 mm   1500 Kg
10 mm  2000 Kg
12 mm  3000Kg
14 mm  4200 Kg
16 mm  5500 Kg



The plait density of the outer cover of a rope has a bearing on how the rope handles and feels.
16-plait is usually soft and flexible.
24-plait is harder wearing but still flexible enough for sheet and control lines.
32-plait is the hardest wearing and usually the best for halyards.


Solid coloured ropes are usually more expensive than white because of the extra process and materials needed to dye the rope yarns. Dyneema® is white and the coloured verions of Dyneema® core are achieved by coating the rope in coloured sealant  like polyurethane which also helps to protect the fibres.

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