HMS MEDWAY and her embarked US Coastguard Law Enforcement team interdicted a vessel carrying over 400kg of cocaine in the Caribbean Sea, 29 Sep 22. Initially spotted by a US Maritime Patrol Aircraft, the ship chased down the boat before the Coastguard boarding team discovered the drugs and detained three individuals. The operation, which lasted overnight, then concluded with the vessel being sunk by Medway’s weapons systems.
A hat tip to our Royal Navy friends. The Navy League’s on line magazine, Seapower, reports,
A Royal Navy ship and U.S. Coast Guard boarding team seized more than 400 kilograms of cocaine worth around £24m on Britain’s streets from a boat in the Caribbean, the U.K. Ministry Of Defence said in an Oct. 28 release.
HMS Medway is a River Class Batch II Offshore Patrol Vessel. The Coast Guard would probably call her a medium endurance cutter. They have a relatively small crew and are faster than Coast Guard WMECs or the Offshore Patrol Cutters currently building.
There is no indication they operated with an embarked helicopter. Operating in the Caribbean they would have had adequate fixed wing support. They have a large helicopter landing area but no hangar. The helicopter in the illustration is a very large one, a Merlin, with a max take off weight of over 32,000 pounds.
The gun on these ships is the same gun and mount as the new Mk38 Mod4.
Chuck Hill's CG Blog 
The Rivers are solid ships. But they are not the best package for that size of vessel.
They weren’t built to be the best package, the Batch 2 were built to fulfil contractual obligations without bothering the naval architects too much (a 57mm main gun and a pair of 30mm on the wings would be a nice upgrade though).
The River class OPV’s are a solid class ships for countries who want an OPV for Coast guard duties
The River class are perfectly capable for Caribbean drug interdiction where they have fixed wing support. They have some advantages relative to the FRCs and 210s that are generally used for this purpose by the Coast Guard. Better range and seakeeping than the FRCs and faster than the 210s or 270s for that matter.
Greatest shortcoming as an OPV is lack of a hangar for a helo, but I think if they would give up the idea of operating Merlins from these they probably have room for a retractable hangar like the one on the 270s and they could operate Wildcat helicopters.
We have already seen River class batch 2 ships built in Thailand equipped with 76mm guns and Harpoons, so increased weapons, if desirable would not be a problem.
The first ships of this basic design that were built for Trinidad and Tobago and ultimately sold to Brazil had a 30mm on the foc’sle and a 25mm on either bridge wing. I should be possible to put a 57mm on the foc’sle and 30mm MSI Seahawk Sigmas with Lightweight Multi-role Missile with on the bridge wings.
https://www.msi-dsl.com/products/msi-ds-seahawk-sigma/
Proud of them both, having worked on both the HMS Medway and served in the Coast Guard.
HMS Medway went South to cover the Falklands/New Georgia in place of a sister ship. https://seawaves.com/2023/04/18/hms-medway-sails-into-a-world-of-stark-beauty-in-the-south-atlantic/