Why Ships Were Once Made Of Concrete

During wartime steel shortages, engineers built massive ocean-going ships out of concrete. These heavy vessels proved to be surprisingly fire-resistant and smooth to ride, though their sheer weight made them notoriously difficult to maneuver.

When steel became too expensive or scarce during World Wars I and II, concrete emerged as a clever, if unconventional, solution for hull construction. While they seem counterintuitive, these floating stone giants were actually quite stable and suffered from less vibration than their steel counterparts. However, the heavy material proved fragile during collisions, and high maintenance costs eventually led to their retirement. Today, you can still spot some of these concrete ghosts resting as breakwaters in coastal harbors.