What is "trysails"

Usage examples of "trysails".

Well before this ominous parallel the frigate's people had been engaged in shifting, packing and storing her light sails and replacing them with much heavier cloth, with storm-canvas trysails and the like for emergency.

It was a cruel hard blow, and the Surprise clawed off from Diego Ramirez and its long tail of rocks as far and fast as ever she could, sometimes making fair headway, sometimes lying-to under storm trysails when the prodigious southern swell compelled her to do so, but always keeping enough sea-room for the comfort of those aboard, every man-jack of whom dreaded a lee-shore more than anything in this world and perhaps the next.

By the time he came on deck Mowett had already taken in the lower studdingsails, and as the night wore on more and more canvas came off until she was under little more than close-reefed fore and main topsails, reefed courses and trysails, yet each time the reefer of the watch cast the log he reported with mounting glee, 'Six and a half knots, if you please, sir.