What is the point with the gaff on the gaff topsail - so you can set another one on the rest of the mast? No that is silly. I note a second doubling, which means she was once full rigged. According to Lubbock many ships once full rigged sailed better as a barque. If so, then for some it must have been a serious deficit to lose the square sails on the mizzen as well, the rig perhaps becoming unbalanced to a degree where she falls off easily, does not steer well, or what do I know - I am just speculating on a short time under sail, and a few books, and I am trying to make sense of that extra gaff. Maybe it is simply so that the second doubling (where the mast-pieces lies beside each other) did not fit a barque's gaff topsail they got cheaply, and it was easier to fashion a new gaff than a new mizzen topmast and topgallant in one piece.