Polish-made 35 mm cannon now aboard MCMV under construction [PHOTOS]

Polish 35 mm Gun: From Loara to naval armament and San

Back in the 1990s, Poland acquired a licence to manufacture the 35 mm KDA anti-aircraft gun, with the intention of deploying it extensively in the Loara self-propelled anti-aircraft systems. Unfortunately, production of the Loara ended after several prototypes had been manufactured, one of which was handed over to the Polish Land Forces for trial operation. 

More than two decades later, the KDA guns were revisited, this time for naval applications. The first development was the OSU-35 naval weapon system, designed for testing aboard the patrol vessel ORP Kaszub. Trials aboard the ship continued for a relatively long period but ultimately produced conclusions regarding the potential launch of series production. PIT-Radwar took responsibility for this production. Importantly, the prototype remains installed aboard ORP Kaszub and is regularly used for live-fire exercises at sea.   

The production systems were designated OSU-35K, and the first two were manufactured for the Project 258 Kormoran II minehunters ORP Albatros (602) and ORP Mewa (603). Both were installed while the ships were still under construction. The first system was installed aboard Mewa in November 2022. Ten days later, it was removed and installed aboard Albatros. This exercise was also intended to verify the compatibility of the ships and their equipment. A similar procedure was carried out at the time with the Kraken Katfish 180 sonar system. The second OSU-35K system was subsequently installed aboard Mewa.     

After some time, the prototype OSU-35K system disappeared from the deck of ORP Albatros. Shortly afterwards, it reappeared mounted on a Jelcz truck as PIT-Radwar’s proposed SA-35 anti-aircraft artillery system. The production version of the SA-35 has been contracted as one of the effectors under the San counter-drone programme. 

Kormoran II - profile of the latest Polish MCMVs

The entire series of Project 258 Kormoran II minehunters is being built by a consortium led by the Remontowa Shipbuilding shipyard in Gdańsk, with the participation of OBR Centrum Techniki Morskiej in Gdynia and PGZ Stocznia Wojenna in Gdynia. Within the consortium, one of PGZ Stocznia Wojenna’s responsibilities is the procurement and installation of naval artillery. The consortium will build a total of six vessels of this type. The prototype vessel, ORP Kormoran (601), is armed with a 23 mm ZU-23-2MR Wróbel-II gun system. So far, there is no indication that it will be replaced by the OSU-35K system. This is technically feasible, of course, but would require minor modifications to the vessel, as well as securing funding for the modifications and the purchase itself.

The remaining five minehunters of this project are to be equipped with the OSU-35K, although, for a time, only one system remained installed aboard ORP Mewa. Production of another four OSU-35K systems was launched at PIT-Radwar for the second group of three minehunters – Jaskółka (604), Rybitwa (605) and Czajka (606) – and for the now-disarmed ORP Albatros (602). The first two of these systems have already arrived in Gdynia. The first (the third OSU-35K system overall) was installed aboard ORP Albatros on 28 July 2026. The second (the fourth OSU-35K system overall) was installed by PGZ Stocznia Wojenna on 29 September 2026 aboard Jaskółka, which is still under construction.

The Jaskółka MCMV has been regularly conducting sea trials from the Remontowa Shipbuilding shipyard in Gdańsk since March 2026. On the day before the installation of the OSU-35K system, the vessel sailed from the Gdańsk shipyard to the shipyard in Gdynia, returning to Gdańsk a few days later. The ship itself is in the final stage of trials and testing. It is scheduled to be handed over to the Polish Navy before the end of this year, after which it will be commissioned into service with the 12th Wolin Minesweeper Squadron in Świnoujście.   

OSU-35K – Naval gun system for Polish warships

The OSU-35K naval weapon system comprises a single 35 mm AM-35K gun, an integrated ZGS-35 tracking head and fire-control stations (a central station in the main command post and a remote station on the ship’s bridge). The AM-35 gun itself has already been fitted with three types of turret: the prototype version aboard ORP Kaszub, the first production version of the AM-35K (the first two units) and the second production version of the AM-35K (from the third unit onwards). The second production version differs, for example, in having an even newer gun housing design.

Another two OSU-35K systems will soon arrive in Gdynia for the final two minehunters, while further systems will be delivered in a few years for the Project 106 Miecznik frigates (two systems per ship).