The AHS "Krab" is a self-propelled howitzer developed to a NATO-friendly standard for the Polish Army. The project was, at one point, a wholly indigenous initiative, set to rely on proven components borrowed from the PT-91 "Twardy" Main Battle Tank (a highly modified Soviet/Russian T-72) and to sport a powered turret based on the British AS-90 "Braveheart" Seld-Propelled Artillery vehicle utilizing the barrel of the French-based Nexter gun system. Design work on the vehicle began in 2000 and saw a prolonged development period eventually producing at least three prototypes, the first being completed in 2008. The effort was headed up the Polish concerns of OBRUM (Osrodek Badawczo-Rozwojowy Urzadzen Mechanicznych) and CPW HSW (Centrum Produkcji Wojskowej Huta Stalowa Wola).
The initiative has since been evolved to become a combination of the South Korean K9 "Thunder" SPA with the tracked chassis of the British AS-90 platform completed with localized fire control system. This has resulted in an early production batch sporting the Nexter Systems gun barrel with UPG tracked chassis while those forms from 2016 onward have the K9 chassis with German Rheinmetall gun barrel.
The Polish Army has received 32 Krabs as of this writing (2020) with the intention to procure a total of 120 systems. Final deliveries are expected in 2024.
While guided and homing missiles tend to receive much play on the modern battlefield, ranged artillery support is still called upon but all armies of the world. The self-propelled gun or self-propelled artillery system has long held a place in war and systems such as the American M109 Paladin, the British AS-90 Braveheart and the German Panzerhaubitze 2000 carry the tradition of long range barrage support to further offensive ground actions at distance. When used collectively, self-propelled guns can provide relatively accuracy fire of large-caliber rounds (High-Explosive, Chemical, Fragmentation or otherwise) against enemy positions to soften resistance or dislodge enemy concentrations. In essence, self-propelled guns are nothing more than self-transporting versions of field artillery systems - the 155mm being the standard caliber of choice for all militaries today. Such systems - either tracked or wheeled in nature - rely in multiple crew, ammunition vehicles and coordinated firepower to showcase their true effectiveness (usually helped by specialized command vehicles fielding extra communications).
Design of the AHS Krab centers around its 155mm main gun barrel which, depending on production batch, was completed by CPW HSW. The barrels were installed into AS-90 turrets supplied by the British concern of BAe Systems. Firing trials were undertaking in 2011. Initially, the Polish Army was intending to build up an inventory of seventy-two Krab gun systems divided into three 24-strong squadrons. Development proved a costly and ponderous affair.
The AHS Krab exhibits a completely conventional design though no less intimidating compared to her contemporaries. The design is essentially a turret mounting a large caliber main gun with a tracked chassis. There are seven road wheels to a track side with the drive sprocket at the front and the track idler at the rear. The glacis plate is shallow and sloped to the hull roof line for basic ballistics protection. The sides of the hull are vertical with the hull roof being completely horizontal. The driver is situated in the front left hull with the powerpack to his right while the turret is set to the rear of the hull roof with full 360-degree traverse. The turret showcases well-sloped facings and, along its forward plate, sports the heavy duty gun mount and recoil mechanism to manage the 155mm main gun barrel. The gunnery crew and vehicle commander take their place in the turret which features a flat roof and rounded access hatches. Storage compartments are fitted to the turret sides while "pioneer tools" can be affixed to the hull roof and sides. The upper track sections are lightly protected over in armor skirts. There is a travel lock at the extreme front edge of the glacis plate for containing the main gun during travel. The crew of five consists of the driver, vehicle commander, gunner and two ammunition handlers. NBC (Nuclear, Biological, Chemical) protection is standard as is night-vision equipment.
The primary Krab form is powered by a single MTU MT881 Ka-500 8-cylinder water-coolr diesel-fueled engine of 1,000 horsepower (quite different from the original S-12U diesel-fueled engine of 850 horsepower, the same as on the PT-91 Twardy MBT). The engine is aspirated through the hull roof while it exhausts along the right side of the vehicle. Maximum speed is listed at 42 miles-per-hour (up from the original 37mph) with an average road speed of up to 20mph under ideal conditions. Operational range is estimated to be in the vicinity of 250 to 280 miles (450 kilometers). Suspension is of the hydropneumatic variety which allows for good cross-country mobility. Fording is up to 1 meter of water.
All told, the Krab weighs in at 106,000lb (down from the estimated 115,000lb in early development) and sports a running length of over 39 feet with a width in excess of 11 feet and a height to the turret roof of 10 feet.
Primary armament of the Krab is its 155mm /52 caliber, twin-baffled main gun barrel that is designed to fire all manner of NATO-cleared projectiles. A trained gunnery crew can let off some six to ten rounds per minute and "smart" munitions are currently in development that will increase range, effectiveness and accuracy on the modern battlefield. Sustained rates of fire are approximately 18 rounds in three minutes. Range of the 155mm main gun is just under 20 miles while assisted projectiles can reach out to 25 miles which put her on par with her contemporaries. There is to be a 60-round storage capacity for the 155mm ammunition throughout the turret and hull. Self-defense against both infantry and low-flying enemy aircraft will be via a single 12.7mm WKM-B Heavy Machine Gun (HMG), also firing NATO standard ammunition and mounted to the turret roof. There are two banks of four electrically-operated 81mm smoke grenade dischargers to either side of the main gun mount on the turret.