Ships are made of steel, which starts life as iron ore. Smelting and processing put energy into the ore, turning it into steel. Corrosion is that energy leaking out, turning the steel back into rust, which is basically iron ore. Energy enters the steel as heat but leaves as electrons.

Do ships rust underwater?

The portion of an iron ship most vulnerable to corrosion is the underwater hull, and this is where corrosion can have the most catastrophic effect. Along with coatings, an effective weapon for preserving the underwater hull is cathodic protection.

Why do shipwrecks decay?

The rate of shipwreck decay depends on several factors, including: salinity levels in the water at the ship's depth. wave action. oxygen levels in the water at the ship's depth.