Brummer-class gunboat

In the mid-1879s, the German Kaiserliche Marine (Imperial Navy) began a program to strengthen its coastal defense forces, beginning with the four Sachsen-class ironclads. Late in the decade, the navy ordered eleven Wespe-class gunboats, which were intended to support the operations of the Sachsens. The Wespes carried a single 30.5 cm (12 in) gun in a fixed mount, with very heavy armor protection. They were intended to beach themselves on the sandbars along the German coastline to serve as semi-mobile coastal artillery batteries.^[1][2] The construction program called for additional ships of both types to be built in the early 1880s, but all of these ships proved to be controversial when they entered service for a variety of reasons. The Wespes were too heavy and slow to be effective warships, and they rolled so badly their gun could be aimed only with great difficulty. And the timing of their construction proved to be unfortunate; they used heavy wrought iron armor just as compound armor was being developed.^[3]

Design work began on a successor design to the Wespe class in the early 1880s that would correct their many deficiencies and was completed in 1883. The new ships incorporated compound armor plate, which reduced weight considerably, as did the decision to omit the heavy belt armor the earlier ships had employed. The large gun was reduced significantly in caliber to 21 cm (8.3 in). Two ships of this design were ordered: Brummer and Bremse. They were the first ship of the German Navy to use compound plate.^[4][5]

The ships of the Brummer class were 62.6 meters (205 ft 5 in) long at the waterline and 64.8 m (212 ft 7 in) long overall, with a beam of 8.5 m (27 ft 11 in). They and a draft of 2.68 and 4.77 m (8 ft 10 in and 15 ft 8 in) forward and aft, respectively. They displaced 867 metric tons (853 long tons) as designed and 929 t (914 long tons) at full load. Their hulls were constructed with transverse steel frames, had a straight stem, and were divided into eight watertight compartments. The ships had a minimal superstructure that consisted of a small charthouse located amidships. They were fitted with a single pole mast for signaling purposes.^[6]

The ships' crew varied over the course of their careers, consisting of 3–5 officers and 62–73 enlisted men. The ships carried a number of smaller boats, including one picket boat, one launch, one cutter, one yawl, and one dinghy. Steering was controlled via a single rudder. Both ships were good sea boats, and maintained speed effectively in a head sea, but they tended to roll erratically and severely in a beam sea. They tended to ship considerable water forward, and had a large turning radius.^[7]

They were powered by a pair of 2-cylinder double-expansion steam engines that were placed in-line and drove a single 4-bladed screw propeller that was 3.6 m (11 ft 10 in) in diameter. Steam was provided by two coal-fired cylindrical fire-tube boilers, which were vented through a single funnel. Each vessel had a pair of electric generators with a combined output of 9.75 kW (13.07 hp) at 65 Volts. Brummer's propulsion system gave her a top speed of 14.1 knots (26.1 km/h; 16.2 mph) at 1,658 metric horsepower (1,635 ihp), while Bremse was faster by more than a knot, making 15.2 knots (28.2 km/h; 17.5 mph) from 2,081 PS (2,053 ihp). The ships carried 68 t (67 long tons) of coal for the boilers. At a cruising speed of 10 knots (19 km/h; 12 mph), they could steam for 1,370 nautical miles (2,540 km; 1,580 mi), though when steaming at 15 knots, Bremse's range fell considerably, to 470 nmi (870 km; 540 mi).^[2][6]

The ships were armed with a main battery that consisted of a single 21 cm (8.3 in) K L/30 built-up gun in an open barbette mount forward. The gun had a range of elevation from -8 to +13 degrees, and it had a maximum range of 7,900 m (8,600 yd). Ammunition supply amounted to fifty shells. This was supported by a single 8.7 cm (3.4 in) K L/24 built-up gun with 75 rounds of ammunition and two 37 mm (1.5 in) Hotchkiss revolver cannon. They were also armed with a 35 cm (13.8 in) torpedo tube submerged in her bow, which was supplied with three torpedoes.^[2][7]

Brummer and Bremse were protected by a compound armor deck that was 25 to 40 mm (0.98 to 1.57 in) thick in two layers. The barbette for the main battery was 160 mm (6.3 in) thick compound steel, backed with 200 mm (7.9 in) of teak planking. It was intended to protect the gun crew from end-on fire.^[2][6]

In 1892, Brummer began use as a training ship for light automatic weapons, and she had a pair of new quick-firing guns of the 8.8 cm SK L/30 type installed.^[5] Later in her career, all of her old built-up guns and the torpedo tube were removed.^[7] The ship underwent another refit in the late 1890s, which included replacing her boilers, increasing the height of her funnel by 1 m (3 ft 3 in), and constructing a platform aft of the funnel.^[5]