French battleship Henri IV

Henri IV was a pre-dreadnought battleship of the French Navy built to test some of the ideas of the prominent naval architect Louis-Émile Bertin. She began World War I as guardship at Bizerte. She was sent to reinforce the Allied naval force in the Dardanelles campaign of 1915, although some of her secondary armament had been removed for transfer to Serbia in 1914. Afterwards, she was relegated to second-line roles before being sent to Taranto as a depot ship in 1918. She was struck from the navy list in 1920 and scrapped the following year.

Design
Henri IV was designed by the famous French naval architect Louis-Émile Bertin to evaluate some of his ideas. She was designed to make her a small target and lacked most of the normal rear superstructure common to ships of her period, other than that needed to keep her rear turret from being washed out. Her rear hull had only 4 ft of freeboard, although she was built up to the normal upper deck height amidships and at the bow for better sea-keeping and to provide for her crew. Her superstructure was narrow and recessed from the hull above the main deck.

General characteristics
Henri IV was smaller than her predecessors, at 108 m overall. She had a beam of 22.2 m and a maximum draft of 7.5 m. She was significantly lighter than the Charlemagne-class battleships and displaced only 8948 MT normally, some 2300 MT less than the earlier ships. Her crew consisted of 26 officers and 438 enlisted men.

Propulsion
Henri IV had three vertical triple-expansion steam engines, each driving one propeller shaft. The engines were rated at 11500 ihp using steam provided by 24 Niclausse boilers and gave a top speed of 17 kn. She carried a maximum of 1100 t of coal that gave her a range of 7750 nmi at a speed of 10 kn.

Armament
Henri IV carried her main armament of two 40-caliber 274 mm Canon de 274 mm Modèle 1893/96s in two single-gun turrets, one forward on the upper deck and the other on the main deck at the rear. The guns fired 255 kg armor-piercing projectiles at a muzzle velocity of 865 m/s.

The ship's secondary armament consisted of seven 45-caliber 138.6 mm Canon de 164 mm Modèle 1893 guns. Four were mounted in individual casemates on the main deck; two more were mounted on the shelter deck with gun shields and the last gun was mounted in a shelter deck turret superfiring over the rear main gun turret. This was the first superfiring turret in naval history and, in this case, was not very successful because the barrel of the 138 mm gun was too short to clear the sighting hood of the turret below. These guns fired 35 - 30 kg shells at muzzle velocities of 730 - 770 m/s.

Twelve 47 mm 40-caliber Canon de 47 mm Modèle 1885 Hotchkiss guns were mounted as anti-torpedo boat guns. They were mounted in platforms in the foremast and mainmast and on the superstructure. They fired a 1.49 kg projectile at 610 m/s to a maximum range of 4000 m. Their theoretical maximum rate of fire was fifteen rounds per minute, but only seven rounds per minute sustained. Two submerged 450 mm torpedo tubes were also carried. Exactly which types of torpedoes carried is unknown, but most of the torpedoes in service during the war had warheads of 110 kg, maximum speeds of 36 kn and maximum ranges of 6000 m.

Armor
Henri IV had a waterline armor belt of Harvey armor that was 2.5 m high and tapered from the maximum thickness of 280 mm that to 180 mm at the ship's ends. The belt ended short of the stern in a 100 mm traverse bulkhead. The lower edge of this belt tapered as well from 180 to 75 mm in thickness. The upper armor belt was mostly 100 mm thick and ran from the bow to 9.1 m aft of the midsection. It was generally 2 m high, but increased to 4 m forward and ended in a 75 mm traverse bulkhead. The maximum thickness of the armored deck was 60 mm, but tapered to 30 mm at the ship's ends. Below this was a thinner armored deck that tapered from 20 mm on the centerline to 35 mm at the edges. It curved down about 91 cm to form a torpedo bulkhead before it met up with the inner bottom. This system was based on experiments conducted in 1894 and was more modern than that used in the Russian battleship Tsesarevich although it was still too close to the side of the ship. The main turret armor was 305 mm in thickness and the ammunition shafts were protected by 240 mm of armor. The casemates for the 138 mm guns ranged from 75 - 115 mm in thickness and their ammunition tubes had 164.7 mm of armor.

Construction and service
Henri IV was laid down at Cherbourg on 15 July 1897 and launched on 23 August 1899, but did not enter service until September 1903, at a cost of ₣15,660,000 francs. The ship spent the early part of World War I as the guardship at Bizerte, until February 1915 when she was assigned to the newly formed Syrian Squadron (escadre de Syrie). This squadron was intended to attack Turkish positions and lines of communication in Syria, Lebanon, Palestine and the Sinai Peninsula. Henri IV was transferred to the French squadron in the Dardanelles campaign to replace the sunk battleship FRENCH BATTLESHIP Bouvet and the damaged FRENCH BATTLESHIP Gaulois after the Allies suffered heavily during their first attempt to sail through the Dardanelles and past the fortifications them on 18 March 1915. The ship bombarded Kum Kale, on the Asiatic side of the Dardanelles in support of the French diversionary landing on 25 April 1915, and provided fire support for the troops ashore for the rest of the month. She was hit eight times while providing support during this time.

Three of her 138.6 mm guns had been dismounted by November 1914 and sent to reinforce the French naval mission to Serbia, known as "Mission D", by rail from Salonica. In 1916, she was assigned to the Complementary (Reserve) Division of the 3rd Battle Squadron. Subsequently she served with the French Eastern Division in Egypt and then she was sent to Taranto in 1918 as a depot ship. Henri IV was stricken from the Navy List in 1920 and scrapped the following year.