using Soviet or Soviet-derived systems. The anti-ship missiles were P-15 Termit derivatives (HY-1, and possibly later HY-2) in two triple-launchers. Guns were two twin gun mounts (SM-2-1 derivatives), and four twin anti-aircraft guns. Anti-submarine equipment were Soviet hull-mounted Pegas 2 and Tamir-2 sonars, depth charges, and FQF-2500 rocket launchers (Soviet RBU-1200 derivatives). The Type 051 was part of the Luda I class. Type 051D The Type 051D was from the second batch. It had changes to electronics and was equipped for underway replenishment. The Type 051D was part of the Luda I class. Type 051DT The Type 051DT was a modernized Type 051D. Kaifeng and Dalian were modernized to somewhat different designs. Kaifeng initially received the Thomson-CSF Tavitac combat data system, the Type 393 surface search radar, and HQ-7 (Crotale derivative) surface-to-air missiles (SAM); the missiles replaced "X" turret. In 1999, YJ-8 missiles replaced the HY-series, and electronic warfare systems were upgraded. Dalian received a similar modernization as Kaifeng. A notable difference was Dalian used the ZKJ-1 combat data system, which was also used on the Type 051Z. They were later equipped with YJ-83 anti-ship missiles. The Type 051DT was part of the Luda III class, and later the Luda IV class. Type 051Z The Type 051Z was a command variant with the ZKJ-1 combat data system. Anti-aircraft warfare capabilities were improved by replacing the 37 mm guns with Soviet guns, and fitting modern Type 381A 3-D radar. One Type 051D, Hefei, was converted to a Type 051Z. The Type 051Z was part of the Luda I class. Luda II The Luda II was a helicopter destroyer. The gun turrets abaft the aft missile launcher was replaced by a hangar and flight deck for two Harbin Z-9C helicopters. One Type 051, Jinan, was converted into a Luda II in 1987 for trials. Type 051G The Type 051G was an improved variant that the last two ships, Zhanjiang and Zhuhai, were completed to. They were equipped with Type 354 3-D air and surface search radar. Four twin YJ-8 launchers replaced the HY-1/HY-2 launchers. The Soviet sonar was replaced by French DUBV-23 search sonar and DUBV-43 variable depth sonar (VDS). Zhuhai was modified in 1999. The Soviet 130 mm guns were replaced by Type 79A guns, derived from French Creusot-Loire Compact, with automated reloaders. An HQ-7 SAM launcher replaced the "X" turret, as on the Type 051DT. Zhuhai was similarly modified. Zhanjiang