ATHENS — MSI Defense Solutions has completed the integration of Leonardo LIONFISH 20 remote weapon systems onto former US Coast Guard Island-class patrol cutters being transferred to the Hellenic Navy under the US Foreign Military Sales (FMS) programme. The project, administered by the US Coast Guard, upgrades the vessels with modern naval gun systems before their delivery and operational use.
The work included structural reinforcement, modifications to turret mounting points, supporting electronics and upgrades to the vessels’ command and control (C2) stations. MSI also conducted engineering assessments and testing to verify the systems’ compatibility, safety and operational readiness.
LIONFISH 20 Weapon System Capabilities
The Leonardo LIONFISH 20 is a remotely operated, fully stabilised 20mm naval weapon system designed for accurate engagement without requiring deck penetration. Its gun has an effective range exceeding 2,000 metres and a burst firing rate of up to 1,000 rounds per minute. The system also supports a controlled firing rate of 100 to 300 rounds per minute and can carry up to 250 ready-to-fire rounds.
The weapon uses standard 20 × 128mm NATO ammunition and weighs approximately 450kg without ammunition. Its coaxial sensor suite includes a daylight camera capable of detecting targets at up to 9.5 kilometres, an infrared sensor with a stated range of up to 12 kilometres, and a laser rangefinder.
A remote-control console allows the crew to conduct surveillance, identify targets and operate the weapon from a protected position inside the vessel. The system is stabilised on two independent axes to support aiming in maritime conditions.
Engineering and Testing
Integrating the modern weapon stations onto older Island-class cutters required modifications to existing ship structures and systems. MSI carried out structural load analysis, recoil-force assessments, sea-state modelling and vessel stability calculations to account for the weapons’ weight and operational effects.
The company also prepared and conducted installation, integration and testing activities outside the continental United States (OCONUS) to verify system performance and confirm the vessels’ readiness before delivery.
Nguyen Trinh, CEO and president of MSI Defense Solutions, said the project builds on the company’s maritime integration work, which began in 2021. He highlighted the technical challenges of installing stabilised remote weapon systems within the structural and spatial limitations of transferred vessels.
MSI has supported FMS programmes involving the modernisation of surplus US government maritime assets before their transfer to allied navies. Its work includes remote weapon station integration, ammunition storage, electrical upgrades, structural reinforcement and command-and-control system improvements.
Four Cutters Modernised for the Hellenic Navy
Four Island-class patrol cutters were transferred from the US Coast Guard to Greece through the Excess Defense Articles (EDA) programme. They arrived in Greece in 2023 and underwent refit and upgrades at Salamis Shipyards before being commissioned into the Hellenic Navy on 20 January 2025.
The vessels were renamed HS Mantouvalos Ioannis (P 197), HS Galanis Georgios (P 198), HS Liaskos Antonios (P 288) and HS Gialopsos Ektoras (P 289). The LIONFISH 20 is installed as their main bow armament.
The Island-class cutters measure approximately 33.5 metres in length, have a top speed of around 29 knots and a range of approximately 1,600 nautical miles at 10 knots. They support coastal patrol missions for the Hellenic Navy, with the new weapon systems providing an upgraded capability against surface threats in coastal waters.
A US Coast Guard contract awarded to MSI Defense Solutions in December 2023, valued at approximately $9.6 million, covered the purchase and installation of the 20mm weapon systems for the Greek-bound cutters. The systems were manufactured in Italy, and the contract period was subsequently extended.
Greece is the first user of the LIONFISH 20 system. The weapon is also installed as a secondary armament on the Hellenic Navy’s new FDI HN frigates, with two mounts per ship.
The completed integration gives the transferred patrol vessels an updated remotely operated gun capability while extending MSI Defense Solutions’ work on modernising legacy naval platforms for allied countries.
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