SS Palo Alto, colloquially known as the Cement Ship, was a concrete ship built as a tanker at the end of World War I. Completed too late to see war service, she was mothballed until 1929, when she was intentionally grounded off Seacliff State Beach in the Monterey Bay, becoming part of a pleasure pier entertainment complex. Palo Alto was damaged by the sea, leading her to be stripped and used only as a fishing pier. Subsequent decades have seen her be further broken by the sea, but large sections of her wreck remain partially intact. She is the sister ship to the .
SS Palo Alto was built by the San Francisco Shipbuilding Company at Government Island in Oakland, California as part of the World War I Emergency Fleet. After the the armistice, any Emergency Fleet ships not already nearing completion were canceled, making the Palo Alto one of only twelve concrete ships to have her work continued. Pouring of her larsite concrete hull began on January 20, 1919. The ship was launched sideways on May 29, 1919, she underwent trials on September 10, 1919, and was delivered that same month. She received her documents on October 23, 1920. She was the first concrete tanker, and the largest concrete ship yet built at the time.
The Shipping Board put the Palo Alto up for sale while still under construction. Various claims have been made as to the results of the sale offer, but she remained in mothballs in the Board's possession in San Francisco until November 26, 1924, when the Shipping Board finally sold her as scrap to Oliver J. Olson & Company for $18,750. . Her documents were subsequently surrendered on June 30, 1926. Her hulk was later purchased by the Seacliff Amusement Company and towed to what would become Seacliff State Beach in Aptos, California, starting the journey at 4 p.m. January 21, 1930, and arriving at 7 a.m. the next day. Once in position on the 25th, she was scuttled in shallow water near the shore.
Settled on the ocean floor, she was refitted as an amusement ship, with amenities including a dance floor, a swimming pool and a café and had the pier built out to connect the shore to her. The opening event was held in her ballroom on June 21, 1930, and "The Ship" opened publicly on June 28. In 1932, as a result of the Great Depression, the Seacliff Amusement Company defaulted on its loans and the ship passed to its creditor, Calavada Investment Company. The ship cracked at the midsection during a winter storm later that year. In 1934, H.R. Lord purchased salvage rights to the Palo Alto from Calavada, dismantling and selling most everything of value. As part of its efforts in establishing Seacliff State Beach park, California purchased the ship for $1 in 1936, and she became a fishing pier.
As a pier, she was a popular site for recreational fishing, but her deterioration led to troubles. Her foredeck was closed for being unsafe in 1958, her masts were cut down in 1959, a 1963 storm split the hull along the 1932 crack, and a January 1978 storm caused parts of her to start listing. A demolition effort was considered in 1978, and after a 1980 storm damaged the pier leading to her, the ship was closed to the public. A 1983 grassroots repair effort led to the ship reopening again on July 23, 1983. Ongoing deteriorating led to the ship closing again for a time in 1986.
Since being placed, the Palo Alto has effectively become an artificial reef for marine life. Pelicans and other seabirds perch on the wreck, sea perch and other fish feed on algae that grow in the shelter of the wreck, and sea lions and other marine mammals visit the wreck to feed on the fish. But in the mid-2000s, an oil spill that had been deadly to dozens of seabirds was traced back to the ship, her fuel tanks having cracked and leaked fuel oil. In September 2006, a cleanup project was started that cost $1.8 million . During the cleanup, workers pumped of oil from the ship and discovered the carcasses of 200 more birds and two harbor seals inside the wreck.
The ship began to roll more severely to the starboard in early 2016, and the entire ship plus parts of the pier were closed to the public once again in the summer of 2016. On January 21, 2017, another winter storm tore the stern off the ship. On January 5, 2023, another winter storm destroyed portions of the pier leading to the ship, leading the state to begin removal of the pier on March 20, 2023, and completing it in May.