Anchorage in River Orwell

Where boats stayed: 51.991° N, 1.263° E

AIS shows only boats that carry it and that a receiver hears, so no boats on AIS never means an anchorage is empty or unsuitable. Boats that live here (at their own berth or mooring, or a week or more in one place) are left out, and boats in marinas and at piers are counted apart from the anchorage's nights. Not for navigation.