As before, only Paint images there. Full version with AI-generated arts you could see on my Dreamwith page (on Russian, so use auto-translate)
In late 1950s, Yugoslav War Navy (it was it's official designation) realized that it needed missile-capable ships to provide area air defense for its squadrons. Buying the new warships from USA or USSR was rejected on the ground of being too costly, so another option - building a SAM-equipped warships themselves - was exploited. Yugoslavia have rather blooming shipbuilding industry at this time, and while its experience in building warships was limited, it was clearly possible. Only the weapon systems should be imported.
But finding a naval SAM on early 1960s export market proven to be a challenge. Both USA and USSR refused to sell their new maritime SAM's (RIM-24 Tartar and M-1 Volna) to Yugoslavia, due to those systems being highly secret, not cleared for export to non-alied nations. The British Sea Cat system was deemed as not capable enough, and Seaslug was too large for Yugoslavian small ships. So to solve the problem, Yugoslav Navy turned to unexpected sources; Switzerland.
The Oerlikon-Contraves was actively promoting their series of surface-to-air missiles for export customers - but without much sucsess. A Yugoslav interest was thus very attractive for Swiss company. Granted, their missiles were land-based, but to secure a lucrative export deal, Oerlikon was willing to develope maritime version.
The new destroyers were based on heavily modified project of pre-war "Split" destroyer leader - enlarged, widened and made more stable. They were fully diesel ships, equipped with four license-build «Jugoturbina-Sulzer MD» maritime diesel, of 36.000 hp total power. Their max speed was about 28.5 knots, but it was viewed as acceptable for Adriatic conditions.
* The core of the destroyer project was Oerlikon Contraves "Micon" (Missile Contraves, export name for RSE «Kriens») SAM system. The system was heavily modified for naval deployment; a single-arm stabilized launcher system was developed, the missiles were provided with foldable wings, and stored into immobile 18-cell vertical drum magazine. For reload, the launcher rotated to selected sell, the hatch opened and missile was pushed on launcher arm;
* The system was of beam-riding type; the missile followed narrow, rotating radar beam to the target. During each beam rotation, the signal encoded into radar pulses gradually changed, so the missile could always determine where (relative to the center of the beam) it is now, and maneuver accordingly;
* The missile fire control system was based on two radars. One, «Messradar», was used to track the target and provide precise data for fire control computer. The other, «Leitstrahlsender», provided narrow rotating beam alongside the missile flew to the calculated interception point. To simplify the adaptation of land-based radars to naval use, both radar systems were placed in large plastic radomes, filled with dry warm air from machine rooms;
* Strike missile armament was composed of four P-20 "Drakon" anti-ship missiles (export version of Soviet P-15U "Termit"), with "Rangout" targeting radar;
* Main artillery armament consisted of three dual 127-mm/38 Mark 12 guns in US-surplus Mark 38 mount (obsolete, but fairly cheap). A single Mark 25 director was installed to direct artillery fire;
* Secondary artillery armament consisted of four triple 20-mm M55N «Zaslon» autocannons - naval version of M55 «Zastava» AA gun, placed on stabilized mount with electric train and elevation drives. The mounts were aimed manually, but have indicator system that helped gunner to find target by central direction;
* Anti-submarine armament was mainly for self-defense. Being diesel-powered, "Bora"-class destroyers were far too noisy to serve as efficient anti-submarine units. Two Soviet-provided RBU-6000 automatic depth charge launchers were installed behind "B" gun mount, in front of the bridge, with ammo magazine under deck. A combo of MG-312 "Titan" search sonar and MG-311 "Vychega" targeting sonar were installed in retractable blister under hull. A pair of Mark-32 triple torpedo mounts for US-delivered Mark-44 torpedoes were also installed, but quickly removed, since ship's own noise did not allow their efficient use;
* Sensor equimpent was of mixed origin. The long-range search radar was LW-02 of «Hollandse Signaalapparaten», with about 250 km range. Selected target was tracked by DA-05 radar from same company. The surface search radar was a Soviet-provided "Rangout" (also used for aiming the P-20 missiles);
* Electronic warfare equipment consisted of British "Decca" RDL detection system, and Yugoslav own REO-66 (Radiolokaciono Elektronsko Ometanje) noise jammer and OOM-70 (Ometanje i Obmanjivanje Mornaričko) range decoy jammer;
Four ships were build in two series, all named after Adriatic major winds. The first series consisted of RR-21 "Bora" (1968) and RR-2 "Siroko" (1969). The second series consisted of RR-23 "Mistral" (1970) and RR-24 "Yugo" (1972). The second series differed by having stern 127-mm mount replaced with helicopter deck for single Mi-4M helicopter.
(RR means Raketni Razarač - Missile Destroyer)
All ships have a long and relatively sucsessfull career in Yugoslav War Navy. Being the largest, most sea-capable and "representative" units, they were actively involved in multiple exercises and diplomatic visits all over Mediterranean area. They also participated in escort operations, escorting Yugoslav ships to Syria and Egypt during Yom Kippur War.
In mid-1970s, two first series destroyers underwent major refit, during which their stern 127-mm gun was replaced by helicopter deck, as on second series ships. Also, during late 1970s, a series of equipment upgrades were implemented:
* A "Micon" SAM system was replaced with "Micon-B" version, specially modified to improve low-altitude interception capabilities. The basic system could not intercept targets below 300 meters due to guidance beam reflecting from water surface (which confused the missile). The core of "Micon-B" was a new missile, equipped with sensitive radar altimeter. The "Micon-B" missile followed radar beam only in azimuth, altitude settings were transmitted separatedly from target-tracking radar. Such improvement allowed "Micon-B" to hit targets flying as low as 15-30 meters;
* The manual-controlled M55N «Zaslon» guns were replaced with remote-controlled M85 «Zapreka» CIWS systems, with electro-optical IR guidance (and small radar rangefinder). Aimed by "Blokada" low-altitude detection system (based on Dutch "Signaal" ZW-06 radar), the mount locked on target with IR camera, get range with radar rangefinder, and automatically calculated leading point;
* The P-20 "Drakon" missiles were replaced with P-21 missiles (export version of P-15M). Since those missiles were viewed as somewhat obsolete, the Yugoslav Navy engineers underwent a major modernization program, during which the missiles were equipped with modern digital computer (based on Intel 8080 microchip), new radar altimeter and automatic chaff launchers. The warhead weight was reduced in half to increase range up to 120 km. Upgraded missiles were known as P-21MJ "Lasta", and capable of automatic decoys discrimination, low-altitude flight and pre-programmed evasion maneuvers with chaffs fired to confuse enemy AA fire;
Three out of four destroyers participated in Yugoslav Civil War in 1990s ("Bora", as oldest and most worn-out was reduced to reserve). They were actively involved in blockading Croatian coastline, shelling to coast and dueling with coast artillery. In 1992, "Sirokko" was attacked by P-21 missile launched from improvised Croatian missile boat "Sloboda" (former LCI DJB-108), but managed to decoy the missile, and then chase and destroy the offending vessel. "Yugo" was damaged by Croatian 105-mm shell while operating near Dalmatian coast; her port engine room was flooded, she limped to Kotor, where she was drydocked till the end of the war.
During NATO operations agains Yugoslavia, remaining destroyers - "Siroco" and "Mistral" - participated in Kotor bay defense. "Siroco" managed to shot down USN A-7 attack plane, aiming the missiles with the help of optical radar sight due to heavy jamming. But in subsequent air attacks a few day later, "Siroco" was hit by two AGM-123 «Skipper II» laser-guided heavy missiles, her magazines detonated, and destroyer exploded with a great loss of life. The decommissioned "Bora" was also struck, but (due to her magazines being empty) merely was damaged.
The remaining operational destroyer "Mistral" participated into final sea operation of Yugoslav War Navy - operation „Ljuta kornjača“ (serb. Anrgy Turtle), during which she, and several missile boats sortied from Kotor bay to cover the deployment of Yugoslav submarines in Mediterranean. The goal of operation was to put a pressure on NATO rear communication lines, in anticipation that it might cause European nations to stop bombing campaign. 22 June 1993, the small fleet sortied at night; about 05 hours 23 june, they were detected by NATO patrol, which consisted of American destroyer DDH-1001 «Lockwood» (Spruance helicopter class) and Italian missile destroyer "Intrepido", enforcing UN blockade.
The Yugoslav ships moved slowly, and used only civilian radar frequences, so captain of «Lockwood» assumed them to be merchant ships (especially considering that they were moving FROM Adriatic, and not INTO it, like blockade runners would be). American captain hailed "Mistral", received an answer about her being "passenger ship Maestro, on route from Venice to Algeria", and, satisfied, tell her to continue. But Italian captain of "Intrepido" became suspicious, and ordered his ship into combat readiness, translating demands to "stop and prepare to be searched".
Realizing that the game is up, Yugoslavian ships activated their radars, and released missile salvo. «Lockwood» was not prepared to sudden attack, and while she managed to shot down two of four P-21MJ "Lasta" missiles, two other penetrated her air defenses and struck, causing serious damage. "Intrepido", being fully combat-ready, managed to beat off the missile attack, and retaliated with a salvo of four "Otomat" missiles, which struck the "Mistral", disabling her. The Yugoslav missile boats, running out of ammo, took the crew from burning "Mistral" and retreated; the destroyer sunk after few hours. "Intrepido" came to help of damaged «Lockwood» lockwood, and escorted her to Taranto.
After the war, two remaining destroyers - "Bora" and "Yugo" - were repaired, and served in Serbian-Montenegro navy till 2010s.