During World War II, Charleston, South Carolina, played a vital role in America’s coastal defense strategy. As German U-boats patrolled the Atlantic and targeted shipping lanes, the U.S. Navy implemented a range of defensive measures to protect key harbors and naval installations—one of the most effective being submarine nets.
Submarine nets were heavy mesh barriers, often made of steel cables and anchored to the seabed, stretched across harbor entrances to prevent enemy submarines from infiltrating. In Charleston, these nets were deployed at the mouth of Charleston Harbor, strategically placed to safeguard the Charleston Navy Yard, Fort Sumter, and vital shipping infrastructure.
Manned and maintained by net tenders—specialized naval vessels—these barriers could be opened and closed to allow friendly ships through. The Charleston Harbor Defense Command coordinated these operations, along with minefields and coastal artillery, forming a multi-layered defense system.
Though Charleston never saw a direct attack, the presence of submarine nets served as a critical deterrent. They exemplified the broader coastal defense initiatives that helped secure the Eastern Seaboard during the war and allowed Charleston to function as a key logistics and ship repair hub throughout the conflict.
Today, the legacy of these defenses lives on in local history museums and in the memories of those who served in the Harbor Defenses of Charleston.