15-cm Kanone 18
When a German army requirement for a heavy gun to arm the new divisional artillery batteries was made in 1933, Rheinmetall was able to land the contract. Using the same carriage as that submitted for the 15-cm sFH 18 competition, Rheinmetall designed a long and good-looking gun with a range of no less than 24500m (26,800 yards), which was well in excess of anything else available at the time. Production did not begin immediately for at the time priority was given to the sFH 18, so it was not until 1938 that the army got its first examples as the 15-cm Kanone 18 (15-cm K 18).
When the army began to receive the weapon it was very happy with the range and the projectiles, but was less than enchanted with some of the carriage features. One of these was the fact that as the gun was so long the gun and carriage could not be towed together except over very short distances. For any long move the barrel had to be withdrawn from the carriage and towed on its own special transporter carriage. The carriage itself was towed on its own wheels and a small limber axle carrying another two wheels. All this took time, an undesirable feature when getting the gun into and out of action, and this time was increased by another carriage feature, the use of a two-part turntable onto which the gun was lifted to provide 360° traverse. This too had to be got into and out of action, and the carriage was equipped with ramps and winches so that even when sectionalized for towing it made up into two heavy loads.
As if the time-consuming installation and removal drawbacks were not enough, the rate of fire of the K 18 was at best two rounds per minute. Not surprisingly, the gunners asked for something better but in the interim the gun was in production and the gunners had to put up with things as they were. As things turned out, many of the K 18s were allocated to static coastaldefence batteries or garrison divisions where their relative lack of mobility was of small account. Not surprisingly, the coastal batteries soon found that the K 18 made a good coastal gun: its long range and the easily-traversed carriage made it ideal for the role, and it was not long before special marker projectiles using red dyes were produced specially for the marking and ranging of the guns.
Production of the K 18 ended well before the end of the war in favour of heavier weapons, But for the guns already in the field a range of ammunition in addition to the marker shells was made available. There was a special concrete-piercing shell with a much reduced explosive payload, and another was just the opposite, being a thin-walled shell with an increased explosive content for enhanced blast effect.
On paper the K 18 should have been one of RheinmetaU's better designs. It had an excellent range and fired a heavy projectile, but for the gunners who had to serve the thing it must have provided the source of a great deal of hard work. Gunners are always trained to get in and out of action as rapidly as possible, whatever weapon they are using, but the K 18 seems to have provided them with something that only hard work could turn into an acceptable battlefield weapon.
Specification 15-cm K 18
Calibre: 149.1 mm (5.87 in)
Length of piece: 8.20 m (26 ft 10.8 in)
Weight: travelling 18700 kg (41,226 lb) and in action 12460 kg (27,470 lb)
Elevation: -2° to +43°
Traverse: on platform 360° and on carriage 11°
Muzzle velocity: 865 m (2,838 ft) per second
Maximum range: 24500 m (26,800 yards)
Shell weight: 43 kg (94.8 lb)