Saltwater vs. Freshwater

Did you know that shipwrecks deteriorate faster in seawater than in freshwater? This is because the iron-based metals that comprise ships corrode much more quickly in saline than in freshwater. The sodium and chloride elements in the saltwater chemically accelerate the process of metal oxidation that leads to rust. This is why huge metallic shipwrecks like the Titanic, the Lusitania, and the Bismarck have decayed so quickly under the water. In contrast, freshwater shipwrecks remain intact with relatively little deterioration.

This is a freshwater shipwreck. Notice how the hull is still very much intact and whole.

This is a saltwater shipwreck. Notice how the metal has given way and caved in upon itself. Also look at how the saltwater currents have strewn the ship’s components to the side.