Just a thought... Given the length of the track the boom is attached to, I imagine that the boom downhaul could be eased and in reefing, the boom could be drawn up to fill that 15" space rather than the sail being hauled down. Don't know what that does to center of effort issues (note ephemeral Physics Sugar Plum Fairies in my head - those thoughts don't last long) After a season of sailing, I'm just thinking of that experiment now. That wouldn't work with a rigid vang system.