HDMS Helgoland was a coast defence barbette ironclad bult for the Royal Danish Navy in the late 1870s. The ship was decommissioned in 1907 and subsequently scrapped.
Helgoland was 79.12m (259.58feet) long overall, had a beam of 18.03m (59.15feet) and a draft of 5.89m (19.32feet).[1] She displaced 5480t[2] and was fitted with a ram bow. Her crew consisted of 350 officers and enlisted men.[3]
The ship was fitted with a pair of Burmeister & Wain compound-expansion steam engines, each engine driving one propeller shaft using steam provided by eight cylindrical boilers. The engines were rated at a total of 4500ihp and gave the ship a speed of 13.4kn.[3] Helgoland carried a maximum of 2240NaN0 of coal that gave her a range of 1400nmi at a speed of .[2]
The ironclad's main battery consisted of a single 30.5 cm gun and four 26 cm guns. The Krupp 30.5 cm MRK L/22 was of the most recent hooped and jacketed construction. It was a rifled breech-loading (RBL) gun mounted in a barbette. Its caliber was 3050NaN0 and its length was 22 calibers. The four single 22-caliber 2601NaN1 RBL guns were placed in the corners of the armored citadel in the hull. For defense against torpedo boats, the ship was equipped with five 25-caliber 1201NaN1 guns.[1] She was also fitted with two 3800NaN0 torpedo launchers.[2]
Helogland had a complete waterline belt of wrought iron that ranged in thickness from 3151NaN1 amidships to 1520NaN0 at the ends of the ship. The barbette and the side of the armored citadel were protected by 260 mm of armor. The deck armor was 520NaN0 thick while the conning tower was protected by 33mm armor plates.[3]
Helgoland, named for the 1864 Danish victory over the combined Prussian and Austro-Hungarian squadron at Battle of Heligoland during the Second Schleswig War,[4] was laid down on 20 May 1875 by the Orlogsværftet in Copenhagen, launched on 9 May 1878 and commissioned on 20 August 1879.[2]