Bolzen-class destroyer

The Bolzen-class destroyers were the second-largest torpedo boat class ever ordered by the Kaiserlich Marine. Officially planning and completing a total of 60 boats from 1906 to 1911. The Pfeil class would eventually succeed the Bolzen in late 1911.

Background
Built on three different shipyards (Helkvertlance & Harvard, Denkingen Co., and Loucherwerft), the boats differed in size and armament, the largest boats were almost a third larger than the smallest ones. Indifference to their predecessors, the Speerwurf class, most of the boats had a turbine engine, only the first 21 had the old-fashioned expansion engine. These were the boats with a top speed about 3 knots slower than the turbine-powered ones.

Very few of these boats survived the Great Sanctus War and were used by the Kaiserlich Marine until being scrapped in the late 1920s.

General Machinery
The boats of the Bolzen class varied in dimensions, and they gradually increased in size as more vessels were built. The boats were 70.2 to 74 meters (230 ft 4 in to 242 ft 9 in) long at the waterline and 70.7 to 74.2 meters (231 ft 11 in to 243 ft 5 in) long overall. They had a beam of 7.8 to 7.9 meters (25 ft 7 in to 25 ft 11 in) and a draft of 2.75 to 3.06 meters (9 ft 0 in to 10 ft 0 in) forward. The hull for each boat was divided into thirteen watertight compartments, though after ST283, they were reduced to twelve compartments. They had a crew of three officers and seventy-seven enlisted men, though from ST283 onward, they had larger crews, with eighty-one enlisted men aboard. When serving as half-flotilla flagships, the boats would have a flotilla leader's staff of four officers and nine enlisted men in addition to the standard crew. The vessels carried a yawl and a dinghy apiece, though later in their careers they carried up to three yawls and the dinghy.

The Bolzen class boats had a variety of different propulsion systems. The first group of boats, from ST266 to ST290, were propelled by a pair of vertical, 3-cylinder triple expansion steam engines that drove a pair of three-bladed screw propellers. Steam was provided by three coal-fired water-tube boilers. The rest of the members of the class received direct steam turbines of various manufacturers. All the boats used the same two-shaft arrangement as the other members of the class, except for the boats ST295 through ST304, which were equipped with six turbines driving three shafts. Steam for both the reciprocating and turbine engines was provided by four marine boilers; the boats from ST266 through ST290 had four coal-fired models, while the remainder of the class had three such boilers and one oil-fired version.

The reciprocating engine-powered boats were rated at 30 knots (56 km/h; 35 mph) from 10,800 to 10,800 indicated horsepower (10,900 to 11,000 PS). The two-shaft turbine boats were rated at 14,600 to 17,300 shaft horsepower (14,800 to 17,500 PS) and 32 knots (59 km/h; 37 mph), while the three-shaft vessels were designed to reach 15,000 shp (15,000 PS) and 32 knots, respectively. The boats had storage capacity for 116 to 194 tons (114 to 191 long tons; 128 to 214 short tons) of coal and, for those boats with oil-fired boilers, 60 to 181 tons (59 to 178 long tons; 66 to 200 short tons) of fuel oil. As a result, cruising radius varied significantly, from 920 to 3,500 nautical miles (1,700 to 6,480 km; 1,060 to 4,030 mi) at 17 knots (31 km/h; 20 mph). Each vessel was equipped with two 17 kilowatts (23 hp) 110-Volt generators for electrical power. Steering was controlled with a pair of rudders, one at the stern and the other in the bow, the latter being retractable.

Armament
The armament for the members of the Bolzen class changed as more vessels were built. The first eleven vessels, from ST266 to ST277 were equipped with one 88 mm (3.5 in) P/95 gun and three 50 mm (1.9 in) P/97 guns in single gun mounts. They carried one hundred 88 mm shells and four hundred and fifty 50 mm rounds. The boats from ST260 to ST265 only carried two 88 mm P/95 guns with two hundred rounds. The remainder of the class carried two 88 mm P/95 guns, also with two hundred shells. The 50 mm guns fired a 2 kg (3.86 lb) shell at a muzzle velocity of 850 m/s (2,789 ft/s). The guns could elevate up to 20 degrees, at a maximum range of 7,100 meters (7,770 yd).

All members of the class carried three torpedo tubes as their primary offensive armament; the first half of the class's tubes were 45 cm (17.7 in) in diameter, and they carried three torpedoes. From ST295 onward, they were equipped with 50 cm (19.6 in) tubes with three torpedoes. All of these tubes were in single, deck-mounted launchers. In their postwar refit, the rest had their original tubes replaced with four 50 cm tubes in double, deck-mounted launchers.

General Characteristics
Dimensions:
 * Displacement:
 * 533 to 700 tons (525 to 689 long tons) (as designed)
 * 684 to 824 tons (673 to 811 long tons) (full load)
 * Length: 70.7 to 74.2 m (231 ft 11 in to 243 ft 5 in) (overall)

Weapons: Engines: Performance:
 * Beam: 7.8 to 7.9 m (26 to 26 ft)
 * Draft: 2.75 to 3.06 m (9 ft 0 in to 10 ft 0 in) (forward)
 * Crew:
 * 3 officers
 * 77–81 enlisted
 * 1 or 2 × 88 mm (3.5 in) P/95
 * 0–3 × 50 mm (1.9 in) P/97
 * 3 × 45 cm (17.7 in) torpedo tubes
 * ST295–ST325: had 3 × 50 cm (19.6) torpedo tubes (postwar refit: 4 × 50 cm (19.6) torpedo tubes)
 * Installed power:
 * ST266–ST290:
 * 4 × coal-fired Scotch marine boilers
 * 10,500 to 10,800 indicated horsepower (10,600 to 11,000 PS)
 * ST291–ST325:
 * 3 × coal-fired Scotch marine boilers
 * 1 × oil-fired Scotch marine boilers
 * 14,800 to 17,400 shaft horsepower (15,000 to 17,600 PS)
 * Propulsion:
 * ST266–ST290:
 * 2-shaft MEE
 * ST291–ST294, ST305–325:
 * 2-shaft steam turbines
 * ST295–304:
 * 3-shaft steam turbines
 * Speed: 33.9 kn (39 mph; 62.8 km/h)
 * Range: 1,086.2 nmi (1,250 mi; 2,011.7 km) at 17 kn; 356.3 nmi (410 mi; 660 km) at 30 kn