Launched in February, 1894, the four-masted ship Dirigo was the first steel square-rigged ship built in Maine, and the first steel ship built in the United States. Designed by a British designer, It was built at the Sewall Shipyard in Bath, using imported steel plates and shipbuilding labor. She was a typical British design of the 1890s. Eight more steel vessels were to follow. Dirigo is the Maine State motto, meaning "I lead" in Latin.

The Sewalls had begun building a series of very large  Down Easters in the 1889, with the launch of the Rappahannock, a series of 300 foot , 3000 tonners. The Rappahannock was a full rigged 3-masted ship, and the Sewalls realized that in this size a fourth mast was needed to make the rig manageable. Subsequent vessels were rigged as 4-masted bark, with a fore -and -aft rigged fourth mast. These were at the limit of wooden ship size, and was the reason that they switched to the British practice of steel. The after mast was called the jigger, and since it  was fore-and-aft rigged like a bark's mizzen, so that these vessels were  commonly called a four masted barks. A more unusual name for the rig was shipentine.