The key to Reliance’s soaring rig was her telescoping topmast, a patented Herreshoff invention. In strong winds the wood topmast was kept down inside the tubular-steel mainmast, but in light airs a below decks winch run the topmast up. The club topsail shown here.its jack yards attached to the topmast and gaff. extended Reliance's rig still farther. towering 175 feet above the water.

from
The boatbuilders of Bristol : the story of the amazing Herreshoff family of Rhode Island : inventors, individualists, yacht designers, and America's Cup defenders

by Carter, Samuel, III, 1904-1988