French shipbuilder the Naval Group recently unveiled an enlarged version of its FDI frigate design.
The FDI XL concept inserts a new hull section amidships, between the integrated mast and the funnel. The insertion of approximately 10 metres would bring the LOA to 132 metres and displacement to an estimated 5,300 to 5,500 tonnes.
The Naval Group said that more powerful engines would preserve the speed of the existing FDI design despite the added displacement. The company also said additional fuel storage would improve range and endurance.
The baseline FDI is rated at 27 knots, with a range of 5,000 nautical miles at 15 knots and an endurance of 45 days.
The illustrated air defence fit combines 32 Aster missile positions in the forward battery with up to 18 VL MICA NG or CAMM-ER missiles amidships, for a total of 50 air defence missiles.
The anti-surface option will double the Exocet MM40 Block 3C battery to 16 missiles alongside the additional surface-to-air installation.
An alternative will retain eight Exocets and add two containers that would hold 336 systems in all, either loitering munitions or drones designed for interception. The Naval Group said the mix would depend on customer requirements.
A third arrangement will replace the extra Exocet launchers and the secondary surface-to-air missile installation with two eight-cell Sylver A50 launchers amidships. The forward silo would then accommodate naval cruise missiles in a 16-cell A70/A70 NG installation, while a separate 16-cell surface-to-air battery would be retained.
The added volume would also house special operations support equipment, communications equipment used to guide drones, and accommodation for unmanned aerial vehicle operators, special operations forces and an admiral's staff.
The Naval Group presented the insertion as an application of growth provisions built into the original FDI architecture.
The concept retains the Thales Sea Fire radar, a 76mm gun, two 20mm cannons, MU90 torpedoes, and hull-mounted and towed sonars.
The FDI XL remains a proposal, with no customer, price, construction schedule or final missile integration confirmed.