Russo-Ukrainian War: The BTS-4M Armored Recovery Vehicle

Source: Sofiia Gatilova (Reuters)

     Rolling through a Ukrainian town in Kharkiv Oblast in March 2025 is a upgraded BTS-4 armored recovery vehicle (ARV). The BTS-4 is the successor to the earlier BTS-2 that entered service in 1955 and utilized T-54 chassis. The BTS-4, on the other hand, used the chassis of the T-55, T-54, and even older T-44 medium tanks (the latter being surplus). The primary difference between the BTS-2 and the BTS-4 is that the BTS-4 added a large snorkel for deep wading. When not in use, the snorkel folds rearwards, laying across the back of the vehicle. The nomenclature of the BTS-4 is actually more granular when it was used in Soviet Army service. The BTS-4 used T-44 chassis, the BTS-4A utilized T-54 chassis, the BTS-4B used pre-production T-54-1 and T-54-2 tank chassis, the BTS-4M used T-55 chassis, and the BTS-4V series utilized T-62 chassis. Externally, they look much alike and the only real way to tell the difference without looking inside the vehicle is by the separation distance between the bogie wheels or other very minor differences. Typically, in Ukrainian Army service, the granular designation isn't always used. In 2020-2021, the Lviv Armored Plant (a part of Ukroboronprom) conducted an upgrade to BTS-4 vehicles in service with the Ukrainian Army.

     The 32-ton BTS-4 (assuming a BTS-4M) is powered by a V-54 diesel engine that develops 520 horsepower. This permits a top road speed of 31 miles per hour though speeds when towing a vehicle are lower with the tow speed being based on the weight of the tank or armored vehicle being towed. Enough onboard fuel is carried to permit a maximum operational range of 310 miles (unloaded). The Ukrainian BTS-4 upgrade increases the weight to 38 tons and replaces the V-54 engine with a more powerful one that develops 580 horsepower but because of the added weight, the maximum speed is reduced to 24 miles per hour. Additional fuel capacity is added in the form of two external fuel drums on the rear but how much additional range this provides isn't stated. The crew of the Ukrainian BTS-4 is three men as opposed to the standard two-man crew of the regular BTS-4.

     Because the BTS-4 is based on the T-55 tank, it shares the same cast steel armor profile. The front hull supports 100mm thick armor though with a 60 degree slope angle on the upper glacis and a 55 degree slope on the lower glacis, the effective armor thickness is higher. The hull sides support 80mm thick armor (without much angling) while the rear has between 20mm to 45mm of armor. The hull roof has 15mm thick armor and the hull bottom has 20mm of armor.

     As befitting a recovery vehicle, the Lviv Armored Plant upgrade swaps out the original BTS-4's 3-ton capacity crane with a new hydraulic driven crane capable of lifting up to 12 tons. The crane is fitted to the left side of the vehicle, the mounting point/turntable situated near the driver's hatch. When not in use, the crane is swung directly backwards along the top of the hull. On the hull front is a dozer blade which is used to clear obstacles, debris, or even dig out a defensive position. The primary winch, with block and tackle, is capable of pulling up to 100 tons. Total cable length is 656 feet. There is also a smaller, secondary winch that also has the same cable length. In the rear of the BTS-4 is a spade that can be deployed to stabilize the vehicle when conducting recovery tasks with the winch. Situated towards the center of the vehicle is a open cargo platform which is used for spare parts, tool boxes, supplies, and other equipment. There are also multiple storage boxes carried on the hull exterior as well as a unditching beam stored just above the rear spade. To assist in field repairs, there is a arc welding apparatus (including a generator) carried on the BTS-4 as standard equipment. From the Lviv Armored Plant, the upgraded BTS-4 includes the snorkel but in the photograph here, it has been removed. In Ukrainian service, the BTS-4 serves as a more economical supplement to the BREM-1 ARV which is derived from the T-72 chassis.

     To date, the Ukrainian Army has lost 19 BTS-4 vehicles with 14 destroyed, 4 damaged, and 1 captured by Russian forces. The Russians, which also utilize the BTS-4, have lost 27 to date with 18 being destroyed, 4 damaged, 4 abandoned, and 1 captured by Ukrainian forces. The Russians have also lost a single, more modern BTS-4V.

Russo-Ukrainian War: The IRM Zhuk

Source: Reddit

     Engineering vehicles, while not glamorous nor getting the limelight of photographic coverage, are an important component of ground forces and the Ukrainian Army is no exception. This particular vehicle, photographed sometime in early June 2025, is fairly rare in Ukrainian service though it has a rather unique purpose. Called the IRM Zhuk, the IRM stands for Inzhenernaya Razvedyvatel'naya Mashina (Engineer Reconnaissance Vehicle) while Zhuk means “Beetle”. A Soviet-era vehicle, the IRM entered production in 1980 and by 1986, only 50 IRMs rolled off the line. What makes the IRM rather unique is that it is optimized for route reconnaissance. U.S. Army manual FM 3-90 Tactics defines route reconnaissance as an “operation to obtain detailed information of a specified route and all terrain from which the enemy could influence movement along that route.” Where able, the U.S. Army would deploy engineer reconnaissance as they have the expertise to evaluate the terrain, bridges, tunnels, roads, trails, gap/water crossings, and other infrastructure to determine not only enemy potential to target assets on the route but also if the selected route is capable of being traversed by follow-on units. To that end, the IRM Zhuk is outfitted to accommodate such a task.

     The 19-ton IRM is based on the BMP-1 Infantry Fighting Vehicle but has a lengthened hull with seven road wheels per side rather than the BMP-1's six road wheels. Power comes from a UTD-20 inline 6-cylinder, water cooled diesel engine that generates 300 horsepower and this provides a top road speed of 32 miles per hour. The IRM is amphibious and mounted on the rear hull are two, 3-bladed propellers within cowls. In calm water, the IRM has a maximum water speed of 6 miles per hour. There is a trim vane on the hull front to keep water off the upper hull. With 158 gallons of fuel, the maximum operational range is 310 miles.

     For protection, the IRM uses all-welded, steel armor but the exact level of defense is not easily obtained but it is thought the maximum thickness is 19mm. This provides the six man crew (commander, driver, and four engineers) with a measure of defense against some small arms and shell splinters. Other protective measures include a NBC (Nuclear Biological Chemical) overpressure-type system (with scrubber) and smoke screen generator. The latter is accomplished by injecting diesel fuel into the exhaust where the fuel vaporizes on the hot exhaust, condenses, then cools which forms a white smoke cloud. Finally, the IRM is equipped with automatic fire extinguishers.

     The only defensive armament consists of a turret mounted 7.62mm PKT machine-gun which is provided with 1,000 rounds in 50-round ammunition belts. Aiming is manual and done using iron post sights. The crew, of course, can utilize their own small arms to defend the vehicle.

     Of course, as a engineering reconnaissance vehicle, the IRM has a lot of tools to perform its tasks. Firstly, the IRM is equipped with a TNA-3 inertial land navigation system. The TNA-3 uses accelerometers and gyroscopes to determine the vehicle's position, orientation, and velocity. A benefit is that inertial navigation systems are independent of GPS and thus not susceptible to GPS jamming and can operate where GPS isn't available. Next, the IRM is fitted with a RShM-2 mine detector which is able to pick up ferromagnetic objects up to a depth just shy of 1 foot. The apparatus is mounted on hydraulically operated arms, one per side of the hull (the right side arm is visible here in the stored position). The arms can be deployed to the front of the vehicle in less than 3 minutes. When using the mine detector, the IRM can drive no faster than 3 miles per hour. If an object is detected, the IRM is automatically brought to a halt. Kept inside the IRM are three hand-held mine detectors; the RVM-2M, IMP-2, and RVM-2. In order to accurately test water depth at river crossings, the IRM has a EIR echo-sounder which can give depth values up to 65 feet. The EIR is paired to a recorder for data retention. To compliment the EIR, the IRM has three sonar transducers which work by sending out sound waves and then detecting the returning echoes. For measuring the azimuth for the purposes of determining both horizontal and vertical terrain angles, the IRM has a PAB-2AM aiming circle. For surveying from within the vehicle, the IRM has an extendable PIR-451 periscope for the commander which includes a DSP-30 rangefinder. Other equipment includes an AGI-1S horizon indicator and a man-portable PR-1 penetrometer. The latter, used by a dismounted engineer, tests for soil crossability and when coming upon ice, the AGI-1S has a ice drill and ice stake to determine ice thickness. For communication, the IRM has a integral R-147 radio set while two portable R-147 sets are kept in store if needed. Finally, the IRM is equipped with TNP-370, TNV-25M, and TNPO-160 periscope observation blocks.