BAE Systems’ 40mm containerized naval gun can destroy drones attacking merchant ships

BAE Systems unveiled a containerized 40 mm naval gun called Sea Tridon C at the Euronaval 2026 defense exhibition in Paris. The company said it is meant for military, government and commercial ships that need short-term or mission-specific protection.

Sea Tridon C packs a Bofors 40 mm gun and an electro-optical fire-control system, which tracks targets with optical sensors, into a container, the UK Defence Journal reported Nov. 3. A BAE image shows the gun on top of a container stack aboard a merchant ship.

The gun fires its 3P ammunition, BAE Systems said, which operators can program just before firing and which has six fuze modes. A fuze is the part of a shell that sets off the blast. The company said the rounds can engage air, surface and shore targets. Sea Tridon C is one of four BAE 40 mm systems that share the ammunition, according to the same UK Defence Journal report.

How the systems differ

The other three systems in the line are Sea Tridon, Sea Trinity and the Bofors 40 Mk4. Sea Tridon is a maritime version of the company’s Tridon concept. Sea Trinity adds built-in radar fire control, which turns it into a close-in weapon system, a gun meant to counter missiles and drones. The Bofors 40 Mk4 is designed to plug into a ship’s combat system.

Lena Gillström, president of BAE Systems Bofors, said there is a “growing need for flexible and effective protection solutions.” BAE said the modular approach also keeps training, logistics and support common across the line.

The Mk4 isn’t new. Shephard Media describes it as a compact, lightweight anti-craft and anti-surface gun. The Dutch and Belgian navies are buying eight of the guns, Ocean News reported, and the UK ordered 10 for its Type 31 frigates in 2020, the UK Defence Journal reported at the time.

Why arming merchant ships is complicated

Maritime Executive reported that BAE and Aselsan, another defense contractor, are both marketing self-contained deck guns for merchant ships at the show. It said Aselsan’s version, called Gokdeniz, pairs a twin 35 mm turret with one container of supporting equipment.

The outlet noted that merchant ships are almost always unarmed in peacetime, and guns on board can raise questions with customs officials in foreign ports and create legal problems for the crew and the owner.

Maritime Executive said several contractors see an opening on high-risk routes such as the Strait of Hormuz, where merchant ships are already being targeted like warships. Its headline says modular guns might reduce the risk of drone attacks on shipping.

Reports so far give no price, customer or delivery date for Sea Tridon C, and no test results. Claims about what the gun can engage come from BAE, and the coverage includes no independent testing. The legal questions the outlet raised about armed merchant ships remain open.

Whether any shipowner or navy buys Sea Tridon C is the next thing to watch.