gooseneck!
at the inboard end of the boom theres a gooseneck(!!!) the aluminium endcap is riveted into the boom extrusion and theres a stainless pin joining it to the other half,this half is inserted into the mast slot where it has been machined wider (about '24 above the base.it then slides down the slot and rests on a fastner stop on the mast.when all is done and the mast is standing the boom will be sitting up above the stop since its attached to the sail .use your cunningham to adjust it properly. check the capri 14.2 website for other stuff! . .have fun!