The one where the rigger leaves a critical nut out of the boom!
The main sail of the yacht is fastened to the yacht in several places. The leading edge (luff) runs up the back of the mast, usually in some sort of track. The base of the sail (foot) runs along the boom also in some sort track. The boom and mast meet at a strong point called the gooseneck. This needs to be articulated so that the boom can move from side to side as the wind changes and the mail sail is set.
On eclipse the goose neck is fasted with a bolt that allows the gooseneck to swing from side to side but not up and down. When refitting the boom to the mast, the boat yard had agreed to fit special ‘top hat washers’ to make up for some wear and tear in the gooseneck, which were not fitted. subsequently when I was looking over the rig and changing some lines I saw this.
There is a large collar washer but no nut to hold it in. A little wiggle and the washer fell out in my hand!
As you can see the bolt that should run from the top of the gooseneck to the bottom doesn’t reach all the way through and there is no nut on the bottom. Potentially allowing the bolt to jump up, and the boom to depart the mast in a catastrophic manner. Fortunately I discovered with before sailing and the chaps at Team Marine in Penarth helped me fashion a new bolt from a stainless rod, threaded at both ends and with a nut welded to the top. This is working perfectly now.