Early monitors were coastal crafts not suited for rough weather. Arranging for a vessel deeply submerged meant that less armour (the armour only stretched for about half a metre below the waterline) was needed and the production was cheaper and quicker. The USS Monitor was needed FAST when it was constructed.

The flaws in the design were evident, and most nations started building raised turret monitors, that had a turret on a fixed tower and a hull and a deck around it. Among the most famous of these are the Huascar.