English: The topsail studding sail (or stun'sail) is set alongside a topsail on a square rigged sailing vessel. The head of the sail is fastened directly to a small yard, with a halyard (i) attached one third of the way along that runs to a block on the end of the topsail yard (and then on to the topmast cap and down to the deck). The downhaul (h) is fastened to the yard at the head of the sail, runs through a thimble positioned half way down the outer leech, through a block at the clew beneath it, then down to a position at deck level. The tack is the rope fastened to the outer clew of the stun'sail, passing immediately through a block on the outer end of the stun'sail boom and then to a belaying point aft, at deck level. The sheets are attached to the inner clew with one part fastened forward and the other aft, both at deck level. The stun'sail boom is shown in it's run-out position - to which it is pulled outwards along the yard by a tackle whose fall is made fast on the yard, close to the mast.