10-inch gun on model 1892 barbette carriage
Cannon: The modern (or breech-loading) era of American artillery began with the development of new rifled breech-loading guns in the late 1800s. The guns used to defend the American coastline were designed by the Ordnance Department of the U.S. Army. These cannon were termed either mortars, howitzers, or guns, depending on their tube length and a few other parameters. They were also classified as
- Primary (16, 14, 12, 10-inch) for use against capital ship with similar armament
- Secondary (8, 6, 5, 3-inch) for use against smaller, faster, lighter armed ships and minesweepers.
Carriages were either fixed (permanently emplaced in a prepared position), or mobile (i.e. had wheels or tracks).
16 inch gun on model M4 barbette carriage in casemate
Barbette carriage (BC) A carriage arrangement in which the gun was fired over a parapet. The carriage was comprised of a set of frames or cheeks which supported the gun tube in a manner that allowed for elevation and depression, on a base that accommodated the firing recoil and that could be moved horizontally. Only a few of these early designs were made for the 8, 10, and 12-inch guns by the early 1890s when the disappearing carriage design was adopted for the heavy seacoast artillery guns.
6-inch gun on model 1900 pedestal mount
Barbette carriage (long-range) (BCLR) A new barbette design of the World War I period allowed for greater firing elevations and ranges for largr caliber guns. It eventually became the standard American seacoast artillery carriage for 6-inch, 8-inch, 12-inch, and 16-inch guns, and these carriages have collectively become known today as barbette carriages (long-range). During World War II new 16-inch BCLRs were protected by modern concrete casemates, while the new 6-inch BCLRs were protected by thick steel shields.
3 inch AA gun on M1917 pedestal mount
Pedestal mount (Ped.) Carriages designed for guns of 7-inch or lesser caliber (the Army guns were generally 3-, 5-, and 6-inch guns). This type of mount consisted of a fixed cylindrical base on top of which rotated the yoke which held the cannon in a cradle equipped with recoil absorbing cylinders. Most pedestal mounts had a frontal shield.
Antiaircraft mount (AA) When antiaircraft gun carriages were developed following World War I, they were technically pedestal mounts, but were always were referred to as AA mounts.
Mortar Carriage (MC) Mortar mounts for firing short 12-inch calibur weapons in high arcs.
Fixed Retractable Carriages
four 12 inch mortars on model 1896MI carriages
12-inch gun om M1897 disappearing carriage
Disappearing Carriage (DC) The prevalent carriage design for heavy American seacoast guns in the period between 1890 and 1917, of which large numbers were constructed and installed. These were further designated, as were all carriages, as either limited fire (LF) or all around fire (ARF) with regard to their traversing abilities. The guns were mounted on one end of a pair of swiveling arms which were counterweighted at the other end. When the catch was released after loading, the falling counterweights would raise the gun to firing position, and the recoil energy of firing would push the gun back down to the loading position. The US Army used this mount for 16-, 14-, 12-, 10-, 8-, and 6-inch guns)
Balanced Pillar Mount (BPM) A trade name for an early modern era retractable carriage for the 5-inch gun which allowed the weapon to be lowered into its emplacement between drills or engagements. The gun and gunners platform rested on a telescoping tube which could be manually cranked up or down.
Masking Parapet Mount (MPM) Somewhat similar to the balance pillar mount, this mount for the 3-inch gun was designated by the trade name used by the manufacturer.
Mobile CarriagesThe mobile coast defense weapons of the post-World War I era were from stocks of weapons originally designed and built for use in European Theater. The availability of these weapons, the new emphasis on mobility in seacoast defense, and the lack of funding for new fixed coast artillery guns, brought a mobile era to coast artillery in the period between the wars.
Railway mount (RY) Several American railway mount designs
12-inch mortar on railway mount
were developed during World War I, most utilizing weapons removed from the existing coast defenses. The most numerous of these remounted weapons were 8-inch guns (on a M1918 BC) and 12-inch mortars, both of which were eventually used for coast defense. A few designs for new 14-inch guns were developed and built by the Navy for use in Europe. The US deployed four Army-built 14-inch guns on railway mounts, two in Panama and two at Los Angeles.
Tractor-drawn mount (TD) Also left over from the war were a great number of truck (initially tractor)-drawn artillery pieces which could be moved along roads. The most numerous of these was a 155 millimeter gun, an American-built (M1918) version of a French 1917 design. This became the standard tractor-drawn coast defense weapon, and with some modifications to the carriage and the addition of pneumatic tires, remained in service through World War II. The guns could be set up to fire at any location by preparing an earthen Field Mount (FM). During the 1920s a simple circular concrete platform was developed in Panama for this gun, and these were called Panama Mounts (PM). Many PMs were built for 155s which were used as temporary defenses at the beginning of World War II.
Click this link to see photos of existing American seacoast artillery