hi
i started sailing again this summer after maybe a decade or more on the couch, i gave away all my old 90's gear and bought second hand gear around the 2006 age and wow what a difference. love this sport. i even did a heli tack today, !!

im wondering ???
if the downhaul says 430 and you want to not fully haul it
do you adjust the mast extn to 428 or
leave 430 and have 20mm of rope through the pullys
or it dosen t matter???
or every band is different

hope this makes sense
thanks

Welcome back r2908.

Generally speaking the Luff measurements are normally indicated on the sail not the downhaul measurements. For example, it might say Luff 438. Luff is the length of the leading edge of the sail so therefore if you are using a 430 Mast you would need to extend your mast extention by 8cm (ie 430 + 8 = 438).

As a general rule you want the gap between the pulley and the bottom of the mast extention to be minimal. For example, if the Luff is 438 and you extended your mast extention by 20 (ie 430 + 20 = 450) and only downhauled to 438 leaving a 12cm gap, this would bad.

Leaving an extra 2cm just in case you need to crank it down a bit more would be ok.

I don't think you can generalise here. Sails are different, some will benefit from a little less downhaul in light winds some won't. Doesn't hurt to experiment and find out.

And then there's the reality that even two sails of the same size and model can be different.

I recently picked up a 2nd hand Naish Sprint 6.6 to replace my existing one that's getting pretty worn, and discovered that I needed an extra 4cm of extension to get the same twist off and feel.

Just another reminder that using the measurements as an approximation only, and to use your eyes.