Tall sail rig for small boats. Originally used in Britain in the 1870's, a vertical gaff-like mast extends the main mast. Still used on some small boats, such as Klepper Folding Boats, because the rig stores within the boat ready for use.

The sail is tightly bound to the top (thin) mast, and loosely bound to the main mast. The topmast, along with the sail, can slide down and fold at the base of the mast. To dump the sail, the topmast is lowered down the main mast, gathering the sail at the base. The entire rig can then be lifted out, wrapped in the sail, and laid inside the boat.