The June 2021 edition of the U. S. Naval Institute Proceedings has a short article by Captain Michael Cilenti, USCG, currently CO of USCGC Tampa, in the “Professional Notes” section, pp 78-79, about the service life extension program (SLEP) planned for six of the 270 foot WMECs. It is available on line if you are a USNI member.
Captain Cilenti, confirms what we have suspected, that the 76mm Mk75 gun and Mk92 firecontrol will be replaced by a 25mm Mk38, the same gun currently used on the Webber class WPCs.
The Captain is concerned primarily because the loss of the Mk92 means the loss of the ships’ most capable radar. The Mk92 is a multi-function radar. In addition to providing firecontrol, it is the ships’ only air search, and its most sensitive surface search. It is more effective in detecting the targets such as low profile semi-submersibles.
Capt Cilenti suggests that there is are alternatives already in or planned for Coast Guard use that could be installed to provide these capabilities. He suggest the AN/SPS-75 (TRS-3D), currently installed on the Bertholf class National Security Cutters and the Freedom class LCS, or the AN/SPS-77, planned for the Offshore Patrol Cutters and currently used on the Independence class LCS.
He notes that the addition of a multi-mode radar would allow the 270s to control emergency helicopter low visibility approaches by the embarked helicopter and facilitate UAS operations.
I hope someone is paying attention to the Captain’s plea. Adding a modern multi-mode radar and a UAS system such as V-BAT, could give us WMECs that are more capable than ever, of performing their law enforcement and SAR missions, while requiring few crew members and less extensive training. Deleting the Mk92 firecontrol system without replacement will leave these ships little more capable than the 210s and probably preclude installation of more capable Unmanned Air Systems.
The 270 SLEPs will begin in the near term. A decision to retain and enhance these ships sensor capability is urgent.
I would suggest that the 25mm Mk38 be mounted up a deck, like the gun of the very similar Irish Naval Service Offshore Patrol Vessel LÉ Eithne pictured below. This would provide a greater degree of protection from green water coming over the bow. (Incidentally that gun is an earlier version of the 57mm being used on the National Security Cutters.)