Additional protection against drones was noticed on the small missile ship "Serpukhov" of Project 21631 "Buyan-M". In photographs from Kaliningrad, the ship is equipped with metal lattice screens above the superstructure and along the sides, and the area of the stern 30-mm AK-630M-2 "Duet" artillery mount is additionally protected with sandbags.
The installed structures belong to the class of passive protection means. Lattice screens are designed to reduce the effectiveness of certain types of ammunition and protect the most vulnerable parts of the hull and equipment.
Additional reinforcement in the area of the artillery mount may be related to the need to increase the ship's survivability against threats from small-sized aerial targets.
The AK-630M-2 "Duet", with which the "Serpukhov" is equipped, is a twin-barreled 30-mm naval automatic close-range artillery mount. The complex uses two six-barreled AO-18 automatic guns and is capable of developing a rate of fire of up to 10 thousand rounds per minute, intended, among other things, for combating aerial targets.
The appearance of such protective elements on the ship shows a change in the approach to equipping warships. If previously the main attention was paid to missile and artillery weapons, now additional means of protection against small-sized unmanned aerial vehicles are becoming increasingly important. Ships of the "Buyan-M" series are gradually acquiring passive protection means against drones. Earlier, anti-drone nets appeared on the MRK "Orekhovo-Zuevo" of the same Project 21631: metal or nylon mesh screens were attached above the superstructure on special support racks. A similar trend is observed in other classes — submarines began to be equipped with lattice structures, similar in principle to "mangals" (barbecues), well-known from T-90M tanks.