Gray is actually a form of camouflage for the ocean environment: it closely matches the color of the sea and sky under most lighting conditions, including the hazy horizon where ships are most likely to be spotted visually. Modern detection, though, happens mostly via radar, sonar, and satellites rather than the naked eye, so hull color matters far less than a ship's radar cross-section and heat signature — which is why navies invest in angled hull designs and radar-absorbing materials instead of elaborate paint schemes.