Hey, I am having trouble with my harness line positioning when changing between sails (only one boom). Can anyone suggest the most accurate way to set these up, at least roughly. I have heard so far -

(1) measure the length of the boom with fists, then count a third of that from the clew and put them there
(2) hold the sail with one hand whilst on shore, when it feels balanced put them there

I find it hard to adjust them when I am out there battling , appreciate your opinions, although I realise I will have to do some adjusting on the water I just can't seem to get them sweet ....

Thanks, p.s. got a starboard Carve 122 / 2006, very sexy & lively, just wants to plane at any given chance, all I need now is some wind in Sydney !!!!!

Guy Cribb has a neat way of doing this. Esentially he just puts the back buckle 1/3 of the sail chord length back from the the mast and then puts the front buckle about 150 mm in front of that. The elegance is in the way he measures it. He has a length of bungee with the third point marked on it with a hook on one end. He hooks it on the clew and stretches the other end to the front of the mast and the 1/3 point is always in the right place for any size of sail.
I myself dont do this. I feel them in on the water and put a mark on my booms later. I was surprised when I looked at my booms recently and noticed that the mark on port side was about 50 mm in front of the starboard mark. ???!!!

i did the guy cribb method - works a charm. if you don't want to do the measure thingy, and your boom has distance markers printed on it you will find the sail will have boom length printed on it - use this number to go with the third idea. Not as accurate as the bungy cord, but a great improvement on stuffing around every run. Instead of the 150mm thing i use the about width of my fist.

Also i used to have harness lines too long - this mean i was not utilising the harness line properly, meaning using more arm than i should - not very good. To get the length right i would then spread the ends of the line further apart, so the harness was working across a larger distance of boom, meaning less chance of aligning nicely to that sweet spot of effort in the sail.

When i did these changes were huge - so much more comfortable - no worries hands off sailing now. Good luck!!!

ps - i find some of the larger sails need to be a little further forwards - although this is more likely how i rig the sail.

Hey, thanks for all your advice, I appreciate it, it's been driving me nuts, shall hit the water and give it all ago. All I need to do now is contact the Big Man in the sky and arrange (1) the wind from Perth to come to Sydney and (2) the weather from Brisbane to come to Sydney. This may be a harder problem to fix

not sure I understand that, how does apparent wind and board speed affect centre of effort?
Sure in badly designed/rigged sails increase in load will shift C.E. back, is that's what is happening?

Well that really surprises me!!!!