Restricted in Ability to Manoeuvre (RAM) (RAM)

A vessel restricted by the nature of its work in its ability to manoeuvre as required by the collision regulations and therefore unable to keep out of the way of another vessel.

The definition applies to specified or comparable operations such as laying or servicing a navigation mark or cable, dredging, surveying, replenishment at sea, launching aircraft, mine clearance or towing that severely restricts course alteration. It does not apply merely because a vessel is large, slow, in shallow water or conducting ordinary work.

A RAM vessel displays prescribed lights and shapes indicating status and, for some operations, its obstructed and safe sides. Other vessels must interpret the complete display and rules; RAM status is encounter- and operation-specific and does not grant an unrestricted right of way.