Swinging Circle And Turning Circle

Swinging Circle And Turning Circle
Swinging and Turning Circles – ship terms related to vessel navigation are often confused.
Swinging Circle is a shipping term used when the vessel is at anchor. This is the theoretical radius in which the ship is expected to swing at anchor. The radius of the swinging circle is generally calculated as (Number of Shackles x 27.5 m + Length of the Ship in meters). After anchoring, the watch officer (OOW) should ensure that the vessel remains within the Swinging Circle and that no other vessel anchors within the vessel’s swinging circle, plus some safety distance as decided by the Master. The swinging circle is not fixed and depends on the number of shackles paid out.
Turning Circle is part of the vessel’s manoeuvring characteristics. It is the diameter circumscribed by the vessel when the rudder is put hard over when going full ahead. This shipping term is generally determined during the vessel’s sea trials before delivery. The yard will provide details of the turning circles in Loaded and Ballast Conditions for shallow and deep waters. Turning circles are posted on the bridge and included in the Wheelhouse Poster, and one need not calculate the turning process each time and for different conditions.