Rope Lengths

To coordinate information for the UK class, we’re starting a collect various rope and wire lengths which we hope will help sailors when they need to purchase something new. This is not going to be a complete list, but we will add to this when additional information is obtained. Please contact the class Technical Officer if you have other helpful information to add here.



All measured between the bearing surfaces. i.e. the surface of the end fitting which touched something else when in use.

Trapeze wires 3180mm – allows for a spliced rope adjuster between the wire and the cleat

Trapeze wire Dyneema adjustable tails - Rope is 1000mm in length each side. Spliced to that when short 320mm and 450mm when extended. 4mm Dyneema

Trapeze adjusters - 2500mm each side. 5mm - e.g. Marlow Excel Control 5mm

Forestay – 4450mm – ensures the mast stays engaged between the mast partners as per Class Rule C.9.2.1 (5). Tested on a Mackay hull, other hulls types could be slightly different.

Shrouds –            4020mm – standard length from Selden when supplied with a new mast. Works on a Mackay, but will be at the top of the adjuster

                               4055mm – Length that works well on a Mackay

Jib luff wire 3700mm

Rig tension wire strop 360mm



Kite sheets 9500mm – 7mm for comfort, 6mm for intermediate, 5mm for light winds. Marlow Excel R8 works well for tapering

Mainsheet – 7000mm 7mm - e.g. Liros Magic Sheet 7mm

Jib sheets – 6500mm. 6 or 7mm  - e.g. Liros Magic Sheet 7mm



Main halyard      2.1 main halyard, buy 19000mm to allow for splicing at the top. This will be overlong. 4mm Marlow Excel Racing has a Dyneema core and therefore works well. A 2:1 is recommended for the keen racer as mainsail load is halved on the halyard meaning the main is more likely to stay at the top of your mast!

1:1 main halyard, buy 12000mm – a 2:1 is preferred, but a 1:1 is cheaper/easier.

Kite halyard - TBC

Jib halyard - TBC


Control Lines

Main Bridle - 1500mm each side. 5mm. Add a little more if you're splicing onto the centre block       

Jin Cunningham - 1400mm 4mm. Purchase 1500mm to allow for splicing.                       


The above information is provided in good faith and intended to be as accurate as possible however, The British International 420 Class Association cannot be held responsible for any incorrect information on this page.


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