Gasket:

Gaskets are small hanks of rope hung in various places on clipper ships.

The Oxford Companion to Ships and the Sea defines a gasket as: A rope, plaited cord, or strip of canvas used to secure a sail, when furled, to a yard or boom of a vessel. In large square-rigged ships gaskets were passed with three or four turns round both sail and yard, with the turns spaced well out.

Gaskets were placed along the top of sails as can be seen in the following picture of the fore lower sail on the model of the Flying Cloud in the Addison Gallery of American Art.

Gaskets were also hung near the lower end of fore and aft sails as shown in the following picture, also of the model of the Flying Cloud in the Addison Gallery of American Art.