For first all-welded hull, see M/S Fullagar.
The M/S Carolinian was the first entirely-welded commercial vessel in the world. She was completed in March of 1930 in Charleston, South Carolina. Built by Charleston Dry Dock & Machine Company, she was a 226-ton tanker designed for coastal shipping. Miles L. Clark is a known owner, with Texaco as the operator (notice the insignia on her stack prior to launch). The ship took about nine months to complete from the time her keel was laid. As denoted by the prefix M/S, the vessel also had an internal combustion main engine. Welded construction and internal combustion engines are staples in modern shipbuilding, allowing the Carolinian to be the first truly modern merchant ship.
Richard F. Smith, the designer, created the lock notch welded system. Charleston Dry Dock & Machine was the sole licensee. The design consisted of steel plates with notches that allowed easy fit-up and welding. Only nine workmen were required to assemble the hull. This design saved one-quarter of the cost, and 85,000-lbs of rivets. The welding required a mere 8,000-lbs of welding wire by comparison.
During the shakedown cruise on March 8, she made 11.5 knots heading out to sea, beyond Fort Sumter. The success of the Carolinian's maiden voyage the following month, and two flawless subsequent dry-dock inspections spurred an "estimate" for six orders of similar ships in 1931.
On March 9, 1934, the Carolinian rescued four fishermen from a squall near Elizabeth City, North Carolina, the hompeort of this vessel. She was under the command of Captain E. R. Outlaw.