I can't tell you the correct mast rake. So why am I replying you wonder...? Well I went to find what the Australians had to say on subject because they seem to know about these technical issues.<br /><br />I could only find something on an archive of the NSW Association Site (they've moved site and deleted their tips) about gaff rigs. It seemed to suggest that there should be 12-15mm gap at the halyard point and that this should increase to 25mm when actually underway with the kicker in tight.<br /><br />But then they also seem to have a load of other variables such as sails, wind and kicker...<br /><br />Because the page no longer exists you'll need a web archiver to retrieve it - try this link:<br /><br />
http://web.archive.org/web/20030522124835/http://herons.freeyellow.com/tuning.html<br /><br />I'll try contacting them and see if we can maybe host some of their older content that was deleted - it seems a shame to loose useful information.<br /><br />Do you have a copy of the Heron Handbook (I don't) but I'd expect an answer in there. Or have you spoke to John Howard - he would almost certainly know.<br /><br />Final option - try increasing the rake and see what happens? (Be sure to post back the result)<br /><br />But is this definitely a mast rake issue and not a kicker issue? I thought as well as giving shape to the sail kickers were their to stop the boom rising up?