I hadn’t looked closely at the end of the boom before.
At first sight the gooseneck looks like a very sturdy construction just needing the surface rust cleaning off and painting or galvanizing. But look again, there is a pin running through at the bottom and if you look really closely its only held in place with a bit of seizing wire. I got hold of the boom at lifted thinking to check just how tight the joint was and found that the whole end of the boom swings up exposing a set of gears inside. I suppose with the boom sheeted down and the vang tightened there isn’t really a problem, but it doesn’t feel well engineered.
The problem is of course that the boom was originally a roller furling boom, hence the gears.