If ferrocement is so cheap and wonderful, why doesn everyone use it?
Ah, a healthy skepticism – excellent. The answer is that ferrocement has a bad strength:weight ratio, hence is poorly suited to mobile applications like ships. Most marine structures are mobile and care about weight. While there was a ferrocement boat movement, and quite a number of ferrocement hulls have been built, stronger, lighter materials like steel (for larger boats) and fiberglass (for smaller ones) are much more common. However, non-mobile marine structures, like piers and docks, often *are* made out of concrete. So are some oil rigs, like the mammoth Troll A { link }. Its not that its perfect for everything, just for large, non-mobile marine structures.
