This makes plenty of sense, but where *do* you put the rivet? Toward the back makes me think of a compressive failure, and on each side seems to be the best answer to a non-mechanical/materials engineer.
The rivet doesn't tend to fail from compression when it's placed at the rear. It, or rather the hole for it, does fail when on the sides or the front.
If you ever look closely at the hole on a broken mast it often looks like the hole has torn open. This is especially the case when the mast is pretty old and has had corrosion in the rivet hole. Not being a scientist type I think the simple reason is that it is much harder to crush the rivet than it is to tear open the hole, especially if there has been corrosion to help it out since aluminum is pretty soft and the mast bends a lot!
I think originally the topmasts had 3 rivets holding the collars on. Besides being overkill, I suspect they contributed to more failure because even when one rivet was at the rear the other two were on the sides.
So as not to hijack the ageing spars post, I copy from it and....
This makes plenty of sense, but where *do* you put the rivet? Toward the back makes me think of a compressive failure, and on each side seems to be the best answer to a non-mechanical/materials engineer.