Restricted in Ability to Manoeuvre (RAM)

A ship that, due to the nature of its work, is unable to keep out of the way of other vessels as required by the International Regulations for Preventing Collisions at Sea (COLREGs).

A vessel classified as “Restricted in Ability to Manoeuvre” (RAM) is one that cannot deviate from its course or alter its movements freely without jeopardising its operational purpose or safety. This designation is outlined in Rule 3: General Definitions, part (g) of the COLREGs and applies to vessels engaged in specific activities that limit their ability to manoeuvre as expected under normal conditions. Examples include vessels laying submarine cables or pipelines, dredging, conducting underwater operations, or servicing navigational aids. Such vessels are granted special consideration under the “pecking order” of vessel priorities at sea, as their restricted manoeuvrability places them at a disadvantage in avoiding collisions.

When a vessel is operating under this status, it must display the appropriate day shapes (a ball-diamond-ball configuration) or night lights (red-white-red in a vertical line) to signal its condition to other vessels. Mariners encountering a RAM vessel are required to take early and substantial action to avoid it, as the RAM vessel is not expected to give way. It is crucial for all vessels to understand and respect this designation to maintain safety at sea, particularly in busy or confined waterways where the risk of collision is heightened.