Headsail HUW default size

Those of you revalidating your 2012 certificate for 2013 will have noted that it is acceptable to use a default HUW (Headsail Upper 7/8 Width) for existing headsails. The default size depends on the overlap of the headsail, and is related to the HTW (Headsail 3/4 Width), and is calculated as follows:

For overlapping headsails with LP/J greater than 1.10, the default is HTW x 0.50.

For non‐overlapping headsails with LP/J 1.10 or smaller, the default is HTW x 0.56.

These default sizes are based on actual measured data for a significant number of sails, and any variation from the default will have a very small effect on rating.

For all newly measured sails we now need the HUW to be declared.

We have produced some simple measurement guides for owners*, please see below (PDF format). 


Gaff rig P, E and mainsail widths


What is headsail HLUmax?

Headsail data on cutter rigged boats


Rig (P, E, J, FL, STL)

Aft rigging drawings

If you have any queries please contact your Rule Authority, thank you.

*If you need an Endorsed certificate for your chosen events, then data will need to be officially measured, again please contact your Rule Authority about this.

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