Trying to get the trim of my new sails right. Seems the triple pulley downhaul required on the modern generation of sails would have ripped my 1980's sails to shreds!

How do I know when I have applied enough downhaul? I figure the looseness of the leach might be an indicator?

Can someone tell me how to recognise the correct level of downhaul for 'light' and 'heavy' conditions?

Thanks,
Harrow.

It's all about twist in the leach and shape at the boom.

When down hauling, watch the way the loose backwards c shape between the battens moves toward the mast, particularly between the top 3 or 4 battens (depending on sail type of course). Generally, for light conditions, you want the loose section section to be near the mast between the top 3 battens, for strong conditions, the top four battens.

At the boom, you want all battens to be free of the mast on no cam sails. The greatest depth in the sail profile should also be at the boom

Pugs

Check the manufacturers specifications on the sail, and check out the website of the sail maker who produced your sail. You may find some advice as to whether the recommended down haul is for "normal" conditions or "maximum" recommended down haul for extreme conditions

Depends on your sail.
Downhauling & outhauling to the specified luff and boom lenghts is a good starting point. Some sails eg north, ezzy have indicators on the leach to show you to which point the leach should be loose for light and for strong winds. For 5 batten wave sails in strong wind the leach should be loose to around the midpoint between leach and mast between the second and third batten from the top. Batten tip position too will vary from sail model to model. The Ezzy wave for example will have its battens still tucked in behind the mast even when fully outhauled.
Best to follow the rigging instructions for your sails and then experiment with minor variations. 2cm more or less can make a big difference.

Wrap your rope round an old bit of broom or axe handle... Simple...

I have a trick to make the rope slide and lock with no knots, but difficult to explain. Let me know if you are interested and i'll post something

Pugs

What holgs said is pretty close to where you want. Downhaul until the loose C falls to halfway in between mast and leach between 2nd & 3rd batten from the top. This is pretty spot on for most sails now, then you can give or take a cm of downhaul either way for conditions.

Your sails will stretch in a bit so should become a little easier to downhaul. Ensure no rope is crossing over and leave it out of the cleat section until the end to cleat it off. I tend to treat downhaul like a rowing machine (not only using arms) spreader bars are perfect for this just make sure your bowline is correct, it should be relatively easy like that unless you have a 9m+ race sail.

You can downhaul so leach is loose right down to boom if need be, check that there is still some induced shape in the bottom of the sail though if it is too flat sail will be twitchy and near impossible to use. Be warned if downhauling past manufacturers suggestions excessively rattling leach can shake the sail to pieces. Most of my sails that arent reinforced in the leach have a layer or 2 of clear tape down the leach now to stop this happening.

if its an older north cammed sail, insert your downhaul lever, downhaul until the lever bends and snaps, then get your tyre iron and downhaul it some more while your fellow sailors bend the mast around a tree. After about 2 hours you should be rigged ready to go.

if its an older KA, it downhauls quite a bit easier so rigging is alot faster. Once downhauled, tie the rig to a tree so it doesn't blow away, and go sailing with the sailbag or boardbag instead.

Thanks all, after a day on the water I have sorted it all out.