Róisín-class

The Róisín-class large patrol vessel is a class of offshore patrol vessels (OPV) utilized by the Irish Naval Service. Ordered from December 1997, the lead vessel of the class, Róisín, shares its name with the class itself and was commissioned in December 1999, marking the beginning of its operational history. Following Róisín, the second vessel named Niamh was delivered in 2001. The class's primary mission encompasses fisheries protection, search and rescue, and maritime protection operations, which include vessel boardings.

The vessels of the Róisín class were designed by Vard Marine (previously known as STX Canada Marine). Their design is based on the Mauritian patrol vessel Vigilant, which was launched in 1995, though the Róisín class excludes helicopter deck and hangar facilities. Notable features of this class are the steel hull and the high level of automation that is integrated into the vessels' systems. This technology enables the ships to be efficiently operated by a relatively small crew of just 44, which includes 6 officers. The designs accommodate operations in the challenging conditions of the winter North Atlantic Ocean.

The Róisín class includes the namesake lead vessel Róisín (P51) and the second vessel Niamh (P52). The operational history of the class has been underscored by a staffing crisis within the Irish Navy, as reported in early 2023. The Irish Naval Service has chosen to mothball the Róisín-class OPVs due to manning issues, which affects the vessels' active deployment and engagement in their core missions.