River-class range and economy suit patrol work

The River class trades combat capability for economical patrol range and endurance. The former HMS Clyde, an extended Batch 1 ship with a helicopter deck, is identified as Bahrain's Al-Zubarah. British Batch 1 ships are about 1,700 tons and Batch 2 ships about 2,000 tons, with a quoted range around 5,500 nautical miles. Endurance varies between roughly 21 and 35 days, with crews of about thirty to fifty depending on the batch. A crane, embarked personnel, and small UAVs support boarding and surveillance. Clyde and the Batch 2 ships have decks able to receive a Merlin helicopter, which is a landing capability rather than a claim of a permanently embarked aircraft. A 20 mm or 30 mm gun and embarked Royal Marines suit fisheries enforcement, border security, and counter-terrorism against lightly armed opponents. The economical cruising hull lacks the protection needed for a contested war zone.