...And I've only just had the bolt-rope cut out of our mailsail to make it loose-footed!! With mid-boom sheeting, I, for one would REALLY
like to know before I go out again.
Which begs the question: I must have seen hundreds of different arrangements over the years, but does anyone know the "optimal" ("best") way of attaching main sheet blocks to the boom in a mid-boom sheeting set-up??
Most sailmakers these days are making loose footed mains as a matter of course.... I think a bolt rope main is almost a special order item nowadays. I'd think if that alone was a big issue it would have come to the fore by now, and there would be recommendations re reinforcing the boom, or at least recommeded practice for block attachment with loose footed mains.
Drilling holes into spars is always an iffy thing... but many boats have such installations and do not experience boom failure, and I'd venture to say that everyone has had an unintended gybe at least a time or two!
From a practical standpoint I'd think that the booms with extruded tracks along the bottom, and the proper padeye fittings to fit those tracks would be the best method (no drilling involved exc perhaps for a set screw to lock the position)
Looking at the Carbon booms on some race boats, they simply put a sling around the boom and attach to that - no drilling either (but requires a loose footed main!).
Mid boom sheeting gives up mechanical advantage - ergo the sail forces have increased mechanical advantage vs the sheet mounting point(s) - I think that any mid boom sheeting arrangement is more prone to boom failure than an end-boom attachment, and the more forward the mainsheet is the higher the potential for this problem.