The famous concrete ship -- the S.S. Selma -- in the foreground, while downtown Galveston, in the background, seems to float on the Gulf of Mexico.

The S.S. Selma is a 7500-ton, reinforced concrete, tanker built in Mobile, Alabama. It was launched on June 28, 1919. She was one of several concrete ships conceived and designed during World War I, but was not completed until after the war. Her length was 420 ft., and had a beam of 54 ft. and a draft with full cargo of 26 ft.. Her displacement, full laden, was 13,000 tons. The Selma marked the first use of shale aggregate expanded in rotary kilns for lightweight structural concrete.

Due to the war, steel was in short supply. Concrete was proposed as a viable alternative material for use in ship building. Marine engineers performed feasibility studies which indicated that a reinforced concrete ship would be practical if the concrete had a compressive strength of 5000 psi and weighed no more than 110 lb/ft.. The Selma's average compressive strength was 5591 psi and the average modulus of elasticity was over 3 million psi, well beyond expectations.

The hull of reinforced concrete was 5" thick at the bottom, tapering to 4" on the sides. It required 2600 yds. of concrete reinforced with 1500 tons of smooth steel rebars.

The Selma served several ports in the Gulf of Mexico quite successfully. Unfortunately she ran aground on the South jetty at Tampico, Mexico on May 11, 1920, creating a sizeable crack about 60 ft. long in her hull. She was towed into Galveston for repairs. Although the damage was repairable, the dry-dock crew lacked the knowledge and had no experience repairing a hull of such material. With no guarantee of proper restoration, the U.S. Government's Emergency Fleet Corporation decided not to gamble.
  A channel 1,500 ft. long and 25 ft. deep was dug to a point just off Galveston near Pelican Island's eastern shoreline. After being stripped of all valuable equipment, she was towed out to her final berth, and laid to rest on March 9, 1922.. This left the hull partly submerged.

The Selma has, over the years, been object of many failed plans to convert her for use as a fishing pier, pleasure resort and oyster farm. Long a source of curiosity and local legend, she remains important to concrete and academic experts as an object of study for her construction and durability following decades of exposure to marine conditions.

The Selma is still quite visible today from the historic marker on Pelican Island and has become an interesting artifact to be viewed by the locals and visitor tourists alike.

Since 1992, besides recognition with a Texas Historical Commission's Official Texas Historical Marker, the Selma has been designated as a State Archeological Landmark by the Texas Antiquities Committee, as the Official Flagship of the Texas "Army", and is listed on the National Register of Historic Places.

The SS Selma rests in a significant site in Galveston Bay, near the "marine battleground" for part of the Civil War's Battle of Galveston in 1863.