 This was exemplified by the fact that most Confederate ironclads were designed with a keeled deep draft hull, as opposed to the Union shallow draft flat bottom hulls (also featured on the Confederate river ironclads of which there were also a number built).This came at a cost however, Confederate coastal ironclads frequently ran aground when operating in inland waters or shallow coastal waters, with more than one being captured by the Union because of it, or being destroyed by their own crews to prevent capture in such circumstances – a fate that befell the CSS "Virginia" as her draft ultimately prevented her escape some time after the Battle of Hampton Roads.Furthermore, even the relatively modest aim of limited seaworthiness was rarely achieved, since the Confederacy had to make do with repurposed and underpowered machinery that was originally designed to power wooden vessels, and were unsuited for powering the now heavier casemate ironclads, seriously hampering their maneuverability and leading to many grounded Confederate ironclads being unable to free themselves without help.