Spanish submarine Peral

Construction

On 25 April 1887, the submarine's construction was finally approved by the government; the keel was laid down on La Carraca on 7 October, although work did not start until two weeks later. Nevertheless, the submarine had already undergone a number of modifications: Peral's original 1885 model conceived of a 61-ton submarine, 18.8 m (62 ft) long, with a beam of 2.52 m (8.3 ft) and a single 40 shp (30 kW) electric motor for a single shaft. The submarine Peral began in 1887 had a length of more than 22 m (72 ft), a beam of 2.87 m (9.4 ft), a draft of 2.76 m (9.1 ft), two 30 shp (22 kW) electric motors geared to twin screws, and a displacement of 77 tons surfaced and 85 submerged.^[10]

Air regeneration in the interior of the submarine was accomplished by an auxiliary 6 hp (4 kW) engine, which passed the air through a sodium hydroxide purifier to eliminate CO₂ exhaled by the crew. In addition, the pump injected oxygen when needed. The same engine which circulated air also drove the bailing pump.

The submarine dived by means of the "depth's device" which drove two shafts of vertical axes located at both ends of the hull, moved by two 4 hp (3 kW) electrical motors to submerge or surface, and to maintain horizontal stability submerged. The ballast tanks had a storage capacity of 8 tons, and were used to stabilize the submarine. In order to navigate, Peral used a bronze magnetic needle installed in the ceiling of the turret. The design avoided any electrical interference. He also devised a periscope, a fixed tube on the turret; by using a series of prisms, it projected the outside world to within the submarine.

The engine-cooling system consisted of forcing compressed air stored in the submarine over the engines, and though the original project had needed 430 accumulators, the final project installed 613 with a weight of 50 kg (110 lb). The total weight of the batteries was around 30 tons.^[10]

The top speed varied with the charge of the batteries. With one-quarter charge, the submarine was able to reach 4.7 kn (8.7 km/h; 5.4 mph), one-half 6.9 kn (12.8 km/h; 7.9 mph), three-quarters 8.9 kn (16.5 km/h; 10.2 mph), knots, completely charged 10.9 kn (20.2 km/h; 12.5 mph).^{[citation needed]} The range of the boat again depended on battery charge level; Peral calculated his original submarine could reach 132 nmi (152 mi; 244 km) at a speed of 6 kn (11 km/h; 6.9 mph). With no means of charging batteries while underway, such as an internal combustion engine, endurance and range were limited.^{[citation needed]}

One of the original features of Peral was an underwater lamp, which enabled the crew to search the sea bottom.^[11] The searchlight had a range of 150 m (490 ft).^[12]

The submarine was single-hulled, and the ballast tanks were located at the bottom of the hull, underneath the torpedo tube. This single torpedo tube was the only weapon in the submarine, with two watertight doors on each end so the submarine could launch a torpedo submerged. Mechanisms used for reloading were simple and fast, and the submarine had three reserves. This was almost identical to the torpedo launchers used in submarines since then.^[7] In order to avoid expenses, the torpedoes Peral launched during the trials were borrowed from torpedo boats, two from Retamosa and one from Barceló.^{[citation needed]}

Trials

The Peral was launched on 8 September 1888, sixteen days before another pioneering electric submarine, the French Gymnote. On 6 March 1889 the Peral's trials started, consisting of handling and surface navigation. On 7 August that year, the submarine submerged for the first time up to the turret; 18 days later fired the first trial torpedo (without warhead); on 5 December submerged to 7.5 m; on 25 December passed the first non-static dive test, sailing at a steady depth of 9.5 meters; and, in 1890 sailed underwater for one hour, reaching a maximum depth of 30 meters in trials.

On 25 June 1890 Peral made two simulated engagements on the cruiser Cristóbal Colón, one at day and other at night. At the daylight trial the submarine was unable to attack the cruiser, as the optical turret was spotted less than 1,000 yards (910 m) away from the cruiser, which had 200 civilian and military guests who obviously expected to see the submarine, a fact that angered Isaac Peral. The simulated night attack was successful. The staff that evaluated the trials of the submarine submitted a report, considering its speed and range insufficient, and being especially critical about the failure of the submarine during the daylight attack and its electric motors. However, overall the report was positive, and a second submarine was ordered, again under the direction of Isaac Peral but also managed by several naval departments. Peral designed a 30-meter submarine of 130 tons, under the condition of choosing the yard where the submarine would be built and the choosing the team to build it. These conditions were not accepted by the authorities, who considered this a refusal by Peral to build the submarine. Finally they ordered Peral to return the submarine to the La Carraca yard where it was built. On 11 November 1890 a decree set the end of the projects of underwater navigation in the Spanish Navy.

Similar figures of performance were only attained about a decade later in other countries. The speed and endurance of the Peral attained World War I standards (in terms of underwater, battery-powered sailing).^[7]

Preservation

In 1890 Peral was withdrawn from service, equipment removed, and the hull stored at La Carraca Arsenal. In 1913 her demolition was ordered but this was not carried out.

In 1929, Admiral Mateo García de los Reyes, first commander of the Spanish submarine forces, managed to reclaim the hull and towed it to Cartagena, putting it ashore at the submarine base.

In 1965 the authorities of Cartagena succeeded in moving the hull to the Plaza de los Héroes de Cavite.

In 2002 was moved to the Paseo Alfonso XII, in front of the port of Cartagena.^[13]

In 2013, Peral was restored and moved to the Cartagena Naval Museum.^[14]