Russia has had a difficult time trying to find export customers for its Bal coastal defense anti-ship missile system. BAL first entered service, with Russian forces, in 2008. On paper, Bal seemed pretty formidable. A Bal battalion consisted of eleven 8x8 trucks including four launcher vehicles each carrying eight Kh-35 anti-ship missiles. The 620 kg (1,365 pound) Kh-35 has a range of 120 kilometers and travels at sub-sonic (about a thousand kilometers an hour) speed while 10-15 meters above the water. A GPS/INS guidance system gets the missile to the general area of the target where the missile radar, with a range of about 20 kilometers, seeks to detect something worth hitting with the missiles’ 145 kg warhead. At that point, the missile drops to about five meters above the water for its final run at the target.
The problem with the Kh-35 was that its typical target was Western warships and Western naves had spent decades developing effective gun and missile-based defenses backed by increasingly powerful electronic defenses to deal with anti-ship missiles like the Kh-35. Israel had demonstrated the effectiveness of these defenses in combat against Chinese versions of the Kh-35 used by Iran-backed militias in Lebanon. Russia had developed larger and more expensive anti-ship missiles that make their final attack run at supersonic (as fast as a rifle bullet) speed. Western navies developed defenses and built target drones that performed like the Russian supersonic anti-ship missiles so that a new generation of anti-missile defenses could be tested. The supersonic missiles were more difficult to intercept but they could be stopped. And ship defenses that could stop the supersonic missiles made it even more difficult for the subsonic Kh-35 to score a hit.
To deal with these problems Russian Bal battalions depended on mass use of the KH-35 against a small number of warships. Each Bal battalion could launch 32 missiles within 15 minutes of reaching its coastal firing site. The vehicles would then move to another area where the reload vehicles could have the four launch vehicles ready to fire again within half an hour. Being this mobile and quick to move is how Bal battalions deal with the risk of being hit by air or sea-launched enemy missiles. One reason for mounting the Kh-35s on trucks was to make it harder for the enemy to find and attack the missiles before they can be launched. These large trucks usually had plenty of hiding places in the coastal region they were assigned to and the troops were always on the lookout for new ones. The heavy trucks used by the battalion were built for off-road use and that meant more hiding places were accessible. While all this made it more likely the Bal battalion would be used, it did not change the fact that the Kh-35 was second rate anti-ship missile.
Russia has been resourceful in trying to overcome these problems. In 2015 they introduced a longer (260 kilometers) range Kh-35U missile, which also had a longer (50 kilometer) range final attack radar. Russia advertised features on the new radar that were better able to overcome enemy electronic defenses. That did not make the Kh-35U a sure thing when aimed at a target but did improve its chances. The longer range meant the Bal battalion could remain further inland when launching its missiles. Two or more battalions could more easily jointly attack one enemy task force with more capable Kh-35 missiles.
The latest new feature enables Bal batteries to receive target information from all manner of aircraft, including UAVs of different sizes. A large number of smaller UAVs capable of sending brief encrypted messages including pictures and GPS coordinates of the target can be quickly used by the latest Bal fire control system. Russia also offers submerged passive (just listen) sonar systems placed offshore and connected to shore by underwater cable. A system like this can secretly track the progress of Kh-35 targets enabling the Bal batteries to stay out of sight and launch a mass surprise attack while avoiding attack by the enemy naval force.
These underwater sensors are an updated version of the American Cold War era SOSUS system that monitored most of the North Atlantic and North Pacific for Russian submarine activity. More recently China has been installing a similar system in the South China Sea, while South Korea has installed its own updated SOSUS off its coasts to detect any North Korean (or Chinese or whoever) submarine activity. One of these small North Korean subs torpedoed a South Korean corvette in 2010 and South Korea is determined to avoid a repeat.
The most recent Bal improvement is a cheaper and nimbler launcher truck, carrying only four Kh-35U missiles. The idea here is to have more launcher vehicles, more widely dispersed and using an improved fire control system to both avoid being detected and attacked while also launching large-scale coordinated attacks on enemy ships offshore.