Both the Union and Confederate Navy used a variety of Army field pieces on their ships during the Civil War as neither had a quantities of standardized naval guns. The North had the much larger Navy. The Confederacy had virtually nine except for a few gunboats at the start of the war. The North's plan was to blockade the South's ports and control the Mississippi River choking off supplies from overseas and down river to the South. While the blockade was fairly effective the South's blockade runners were also effective. The war saw the development of ironclads and the battle between the Monitor and the Merrimac at Hampton Roads in 1862 showed the future of naval ships and warfare. The South did usher in a new aspect of naval warfare during the war with the introduction of torpedoes.