Join Date: Jun 2005
Location: New Orleans
Thanked 35 Times in 32 Posts
Rep Power: 10
You've explained the problem pretty well, but from what you've said, I don't know if you have the original mainsail (which should be properly tensioned along the mast without the boom (gooseneck, same thing for your purposes here) being in the open slot. But since it sounds like that's what's happening for you when you raise the main all the way up to the masthead, I suspect you're dealing with a replacement mainsail that's not designed for your boat.
What to do? Well, let's assume your mainsail, wherever it came from, is just 6-10 inches too short. If so, then what you've been doing (raising it as far as you can to get decent luff tension without putting the gooseneck into the open slot) is probably the best solution you have. In which case, just go sailing and don't worry about what others think, even if the peak of the main is 10 inches from the top of the mast. Within a foot or so, there's really no "proper" altitude for the boom, as long as the sheet and vang lead okay and you can duck underneath it when you change tacks.
Or you can shop for a new mainsail, which has the right luff and foot measurements for your mast and boom.