Many thanks for the responses here.
OK I think I understand the concept
... except that it seems to me that if you are not pointed directly into the wind
when raising / lowering the sail you will invariably break the Dutchman lines. Or if you let the sail billow out too much at any point the same result is likely.
I guess that's a GOOD thing and the ultimate 'carrot & stick' approach to teaching me how to trim the main
Info I've found on the web also indicates that you should not have to adjust the topping lift at all once you're setup right. The attachment 'flaps' at the foot of the sail are supposed to provide slack in the lines when the sail is tensioned. That's the 'sweetspot' I'll try to adjust my rig for.
A related question now comes to mind... should I have a shackle on the main halyard
? Right now I just tie a bowline to the sail head
when I get underway (I move the main halyard away from the mast
to avoid that incessant slapping against the mast
in port). I know that tying a new bowline every time I raise the sail may change the distance from the masthead sheave to the sail head
- depends upon how large or small I make the loop in the bowline. This could change the geometry and require me to readjust the topping lift each time.... and that affects the Dutchman lines... yadda yadda...
So do I really want to put a snap shackle on the main halyard? If so what type (snap, bow, 'D') shackle is best for this application? How do I guess what working load / size shackle to use?