Armament
The main armament was ten 12-inch Mark XI 50-calibre guns, arranged in five twin turrets. More correctly referred to as hooded-barbettes, the term "turret" had by this time entered common usage. "A" turret was positioned on the forecastle on the centre line. "P" and "Q" turrets were arranged en echelon on the main deck with "P" on the port side being forward of "Q" on the starboard. The wing turrets had a theoretical arc of bearing on the side on which they were positioned of some 170 degrees, that is to say from five degrees off the bow to five degrees off the stern. They also has a limited arc of fire on their opposite beam if the other midship turret were to be disabled. "Y" turret was situated on the quarterdeck at main deck level, and "X" was immediately forward of and superfiring over "Y" at quarterdeck level. The arcs of fire of "A", "X" and "Y" were all some 270 degrees. The weight of the shell fired was 850 kg, and the maximum rate of fire per gun was two rounds per minute, although allowing for spotting of shell fall one round per minute was the anticipated battle rate.
The secondary armament consisted of sixteen 4-inch (102mm) Mark VII guns in single mountings. In order to maximise the effect of these guns in their primary role of defence against torpedo attack by small craft ten were carried in the forward superstructure, it being assumed that most torpedo attacks would be launched from forward of the beam. The remaining six were carried in the after superstructure. In 1917 three of these guns were removed, and a 4-inch anti-aircraft gun and a 3-inch anti-aircraft gun were added.
Four 3-pounder (57mm) guns were also carried high in the superstructure.
In common with the majority of battleships of the period, Colossus was equipped with torpedo tubes. They were contained within the hull and discharged underwater, being positioned one on either beam and one aimed directly astern. The weapons carried were 21-inch (533mm) Hardcastle torpedoes, with a maximum speed of 45 knots (83 km/h) and an effective range of some 7,000 yards.
Read more about this topic: HMS Colossus (1910)