7 de Agosto class Destroyer

Colombian Navy Destroyers (1958-1985)

Colombia Day ! Probably the most specific and famous ships of the Colombian Navy in the Cold War: Ordered in 1954 these modified Swedish Halland class destroyers mounted a different armament, more electronics, different interior arrangement, and were built on purpose at Gotawerken and cockums from 1955 to 1958. ARC 7 de Agosto (D-06) was originally laid down in November 1955 as 13 de Junio, at Götaverken, Gothenburg differing by a third 120 mm turret in place of a 57 mm AA turret. “13 August” was completed on 31 October 1958 and a career of almost 30 years, scrapped in 1984. Her sister D05 VEINTE DE JULIO was launched in June 1956 and commissioned in June 1958, she was discarded much later in 1985. Both were refitted in the US in 1975-76, included a machinery overhaul, 25 kts top speed, new Dutch electronics, M4 radar director.

Design of the class


The deal between the Colombian Navy and Swedish Government in 1954.

The Halland-class were two destroyers built for the Swedish Navy in the 1950s, in the continuation of a modernization to replace 1930s generation destroyers. Initially, four ships were planned. However, the second pair, Lappland and Värmland, was cancelled but budgetary reasons, and instead, they were sold to the Colombian Navy, after modifications asked by the latter. This became the 7 de Agosto class, and they had many more years of service compared to the Swedish Halland class.
The Halland class were preceded by the öland class, and improved on many points. They ended as well-rounded general purpose surface combatants, first in Europe with antiship missiles. Next were the Östergötland-class destroyer. The Colombian variants were modernized but remained with their original anti-surface focused armament until decommissioned in 1986, the Swedish ships being retired in 1982.

Hull and general design

Being identical to the original Halland class expect swapping a turret, the 7 de Agosto class displaced 2,650 tons standard and 3,300 tons full load, for an overall length of 121 m (397 ft), a beam of 12.4 m (40 ft 8 in) and a draft of 4.7 m (15 ft 5 in). The design was still very much a ww2 style, with a forecastle and aft lower deck, artillery fore and aft, rocket launchers, torpedo tubes and AA guns, making for a well-rounded armament. With them, the Colombian Navy had large surface combatants, almost as valuable as cruisers. The sticking point of the Halland class compared to their contemporaries were their very large bridge, notably compared to relatively thin funnels amidships, giving them an unusual appearance. The tall bridge was made in light metals to alleviate stability problems, but the design had very little room for additions with a metacentric height that was already topping its limits. They came out with a crew of 248, the largest in the Cold War Colombian Navy.


ARC 7 de agosto as completed

Power plant

The propulsion consisted in two 3-bladed bronze propellers mated to two shaft De Laval double geared turbines, fed by two Penhoët boilers for a total rating of 55,000 hp (41,000 kW). Top speed was 32 knots (59 km/h). They carried 524 tonnes of oil making for a range of 3,000 nmi (6,000 km) at 19-20 knots (37 km/h), down to 445 nmi (824 km) at 35 knots (65 km/h) absolute top speed for a short run.

Armament

Bofors 120mm/50 M/50

The main difference with the Halland class was the replacement of a twin 57 mm Bofors AA on “Y” position by a third 120 mm turret. The turret was dual purpose to some extent, but mostly seen as anti-ship capable, however they shared a single cradle mount, and thus, dispersion was an issue, alleviated by the usual firing delay between the two guns. It seems their side-mounted flare rockets were dismounted on photos.
⚙ specifications Bofors 12 cm/50 M50
Full turret and mount weight 67,000 kg (148,000 lb).
Barrel length L/50 including breach, for 120 millimetres (4.7 in) cal.
Shell: 120 × 835 mm R 23.35 – 23.5 kg
Action: Automatic extraction with integrated autoloader
Elevation/traverse: -9°/+85° at 25°/s and 360° at 22°/s
Rate of fire: 2 × 42 rounds/min
Muzzle velocity: 835–850 m/s (2,740–2,790 ft/s)

Torped 613 (TP613)

The 7 de Agosto class had a single torpedo tube bank aft of the second funnel as a compensation for the replacement of the 57 mm for a 120 mm. The space was used for the Bofors 40 mm notably.
Torped 61 Specs:
1,8t, 7 m long, 533 mm calibre, Warhead 300 kg HE with proximity fuse.
Powered by Alcohol and HTP (piston engine) at 50kts over 20 km, wire guided with controlled homing.

Bofors 40mm M/48

Unlike the completely covered twin M/48 as for the öland and Halland class which had three, the 7 de Agosto had simpler and lighter single mounts under shields.
The Bofors M/48 fired an AB 40 mm L/60 HE-T weighting 2.05 lbs. (0.93 kg) full, complete round 17.60 in (44.7 cm) and about 0.661 lbs. (0.300 kg) propellant for the HE 4.63 lbs. (2.1 kg) which carried 0.150 lbs. (0.068 kg) TNT for the HE-T 7a.
Muzzle velocity was 2,789 fps (850 mps), with a barrel life between 9,600 and 10,000 Rounds. Bofors produced 11 Naval guns for the Swedish Royal Navy, 61 for export prewar and in wartime 320+ guns for the Swedish Royal Navy alone, 38 postwar, production ended in 1954. Some of the twin water-cooled mounting had integral 1.25 m or 2.0 m Hazemeyer rangefinders.

Bofors 375 mm M50 ASWRL

The 7 de Agosto class destroyer had two Bofors 375 mm anti-submarine rocket installed on the foredeck, forward of “A” turret.
Specs:
375 mm (14.8 in) calibre, Solid fuel rocket.
Maximum firing range 3,625 m (11,893 ft)
Warhead: High explosive, with Acoustic Proximity Fuse
It is not clear if they also had depth charge racks and launchers as for the Halland class.

Sensors

LW-03/SGR-114 radar: The LW-03 (LuchtWaarschuwingsradar) is a Dutch long-range air surveillance radar operating in the L band, a modernized version of the LW-02 with improved anti-jamming characteristics and same antenna. It was developed in the late 1950s. Range was 120 NM (220 km).
DA-02/SGR-105 radar: Dutch model, improved DA01 (Doels Aanwijzing, “target indication”) working in S-band.
Six M45 radars: These were related to fire control for the main 120 mm guns and 40 mm Bofors.
Sonar: Swedish sonar (unknown type) housed in a retractable dome under the bow.

⚙ specifications

Displacement 2650t standard: 3300t full load
Dimensions 397ft 2in pp x 40ft 7in x 15ft 4in max 121.1 m x 12.4 m x 4.7m
Propulsion 2-shaft De Laval double red. g. turbines, 2 Penhoët boilers 55,000shp.
Speed 32 kts
Range 3000 nm at 20 kts or Range 450nm 18 kts speed
Armament 3×2 Bofors 120mm, 4×1 40mm Bofors AA, 1×4 533mm TT, 375mm Bofors ASWRL
Sensors Radar LW-03, DA-02.
Crew 248

Career of the 7 de Agosto class

Colombian navy ARC 20 de Julio (D-05)


20 de Julio (D-05) or Veinte de Julio (“20 july”, Colombian Independence Day) was built at Eriksbergs Mekaniska Verkstad in Gothenburg, launched on 26 June 1952 and commissioned by the Colombian Navy on 15 June 1956. During her 26 years of operational life she did not take part in any major actions, except for periodic exercises with US Navy (UNITAS). She was decommissioned in 1986 and later scrapped after a career that spanned almost 30 years.
The date of 20 July marked the start of the revolution initiated by the criollos in the capital of the Viceroyalty of New Granada against the Spanish Empire.

Colombian navy ARC 7 de Agosto (D-06)


7 de Agosto (D-06) (ex-Trece de Junio) (D 06), built by Götaverken, Gothenburg. She was laid down in November 1955 as Trece de Junio and renamed when launched on 26 June 1956, commissioned on 31 October 1958. During her 26 years of operational life, she never participated in any major actions, except for periodic exercises with US Navy ships. She was decommissioned in 1986 and later scrapped. For anti-submarine warfare, there was a hydrophone housed in a radome under the fore-body, which could be retracted into the hull when the hydrophone was not in use.
A French sources states their stern was modified to launch the Saab Robot 08, but it’s not confirmed in any other.
The prefix “ARC” stands for Armada de la “República de Colombia”.
The date of 7 august corresponds to a holiday commemorating the day in 1819 when the Battle of Boyacá was fought, the Spanish Army gave up its weapons and the Freedom Army led by Simón Bolívar was victorious.


ARC 7 de Agosto, From Pinterest


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Books

Borgenstam, Curt; Insulander, Per; Kaudern, Gösta (1989). Jagare: med Svenska flottans jagare under 80 år (in Swedish). Västra Frölunda: Marinlitteratur.
Gardiner, Robert; Chumbley, Stephen (1995). Conway’s All The World’s Fighting Ships 1947–1995. NIP
Hofsten, Gustaf von; Waernberg, Jan; Ohlsson, Curt S. (2003). Örlogsfartyg: svenska maskindrivna fartyg under tretungad flagg.
Stockholm: Svenskt militärhistoriskt bibl. i samarbete med Marinlitteratur.
Curt Borgenstam, Per Insulander et Gösta K audern, Jagare: med Svenska flottans jagare under 80 år, Västra Frölunda, Marinlitteratur, 1989
Robert Gardiner et Stephen Chumbley, Conway’s All The World’s Fighting Ships 1947–1995, Annapolis, Maryland, USA, Naval Institute Press, 1995
Gustaf von Hofsten, Jan Waernberg et Curt S. Ohlsson, Örlogsfartyg: svenska maskindrivna fartyg under tretungad flagg, Stockholm, Svenskt militärhistoriskt bibl. i samarbete med Marinlitteratur, coll. « Forum navales skriftserie, 1650-1837. 2003

Links

cyber-corredera.de 185
armada.mil.co ceremonia-de-bautizo
cyber-corredera.de/ 253.pdf
reportedebatalla.wordpress.com 20-de-julio
web.archive.org navypedia.org/ 7 de agosto
facebook.com ArmadaDeColombia 7 de agosto
facebook.com destructor 7-de-agosto replica
en.wikipedia.org ARC_20 de Julio (D-05)

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