like a castle and had bastions with 4 cannons on each bastion. The kotta mara could resist the Dutch 30-pounder cannons until 24.5 m range, the range which the cannon could effectively penetrate it. Floating batteries were popularly implemented by both the Union and the Confederacy during the American Civil War. The first was the Confederate Floating Battery of Charleston Harbor, which took an active part in the bombardment of Fort Sumter in April 1861. Experimental ironclad vessels that proved too cumbersome or were underpowered were often converted into floating batteries and posted for river and coastal waterway control. Here too, Civil War batteries and even ironclads such as the famed monitors, were acutely vulnerable to mines protected in turn by forts. As a result, the combined defences of Charleston, South Carolina, for example, were never overwhelmed by the Union Navy. See also United States floating battery Demologos Arsenal ship References Bibliography Naval artillery Ship types