I think Simon could probably help a bit more here, but if your harness line is falling out, you are taking too much pressure from the boom through your arms and not the harness. This is pretty much the only way a harness line can fall out of the harness hook when blasting along. Do you adjust your harness lines between your 6.0 and 5.0? If not then you will always be fighting your rig without balanced lines and this can cause the line to fall out, as you will have to use more arm strength to hold the boom.
To balance your harness lines, move them (2-3 cm at a time max) towards the hand that has more pressure on it when planing in the straps. Once you have balanced your lines you can apply more mast foot pressure easily and keep the bord flatter. You lines will not necessarily line up on both sides of the boom but this is nothing to be concerned about. This will make a more stable platform to go over chop and hence use less arm pressure and sail longer as well.
Enjoy

Drive your bum if a seat harness or back if waist harness as hard as you can away from the boom. Let you legs flex over the chop and drive-push hard on your fin. Drop your shoulders & relax. You will go faster and sail longer. You may also want to have your hands closer together on the boom. This will push your body further from the boom.

I will keep an eye out for you. I'm on Black Tushi's,Rocks with a Naish Super Cross. Generally sail out in the bay not in the pond. Make yourself known to me & I will help you.

Deano

Hi Paddy,
You could not go too wrong following Dean's advice . It is spot on . As you approach chop you are probably tenseing up, resulting in more pull from your arms, and thus less from the harness, which results in you coming unhooked. Follow Deans advice and you'll have it sorted.if you still are having problems, get Jay or Tom to have a quick look at you on the water the next time you are down,it should be easy to sort out.


Simon
[email protected]
www.gowindsurfing.com

I agree with WestOzwind.

Probably taking too much load in the arms and that's probably because of harness line position...

I think Eastie's referral to Guy Cribb is the way to go.
I found his 1/3 rule to be right on when setting up gear after a long break.

www.guycribb.co.uk/userfiles/documents/The%20Truth%20About%20Harness%20Lines.pdf