Restricted in ability to manoeuvre
Also written: RAM
A vessel whose work — cable laying, diving, dredging, towing — stops it from keeping out of other ships' way.
The Collision Regulations give right of way to vessels restricted in their ability to manoeuvre, because the work they are doing — laying cable, supporting divers, dredging, replenishing at sea — prevents them from altering course or speed. Such vessels show the ball-diamond-ball day shape, or red-white-red all-round lights at night.
Many operational warnings exist to tell ships in advance that a vessel with this status will be in an area, so they can plan to keep clear instead of meeting it.
What the archive shows
8 messages in this archive use “Restricted in ability to manoeuvre”, the earliest issued 1999-06-25 and the latest 2023-03-19. None of them is in force in the latest lists we collected. A hazard reported again and again counts once per message.
8 recorded messages form a small sample; the warning type breakdown should be read as individual records rather than a pattern.
Located messages that use it fall in 3 sea areas; the most frequent are Black Sea (6), English Channel (1) and Yellow Sea (1).
By warning series: HYDROLANT 7 and HYDROPAC 1.
Messages using it, by year of issue
Where it appears · 3 sea areas
How it reads in recent messages
- HYDROLANT 603/23 · Other · Black Sea2023-03-19
…2. THE HSTC IS 83NM LONG AND 3NM WIDE. WHEN TRANSITING THE HSTC VESSELS ARE CONSIDERED RESTRICTED IN THEIR ABILITY TO MANEUVER AND SHOULD DISPLAY THE APPROPRIATE LIGHTS/SHAPES. VESSELS MUST TRANSIT BETWEEN 0500…
The black sea grain initiative jcc has established a route for vessels inbound and outbound of ukrainian ports → - HYDROLANT 2975/22 · Other · Black Sea2022-11-19
…2. THE HSTC IS 83NM LONG AND 3NM WIDE. WHEN TRANSITING THE HSTC VESSELS ARE CONSIDERED RESTRICTED IN THEIR ABILITY TO MANEUVER AND SHOULD DISPLAY THE APPROPRIATE LIGHTS/SHAPES. VESSELS MUST TRANSIT BETWEEN 0500…
The black sea grain initiative jcc has established a route for vessels inbound and outbound of ukrainian ports → - HYDROLANT 2104/22 · Other · Black Sea2022-08-25
…2. THE HSTC IS 83NM LONG AND 3NM WIDE. WHEN TRANSITING THE HSTC VESSELS ARE CONSIDERED RESTRICTED IN THEIR ABILITY TO MANEUVER AND SHOULD DISPLAY THE APPROPRIATE LIGHTS/SHAPES. VESSELS MUST TRANSIT BETWEEN 0500…
The black sea grain initiative jcc has established a route for vessels inbound and outbound of ukrainian ports → - HYDROLANT 2090/22 · Other · Black Sea2022-08-23
…IS 83 MILES LONG AND THREE MILES WIDE. WHEN TRANSITING THE HSTC VESSELS ARE CONSIDERED RESTRICTED IN THEIR ABILITY TO MANEUVER AND SHOULD DISPLAY THE APPROPRIATE LIGHTS/SHAPES. VESSELS MUST TRANSIT BETWEEN 0500…
The black sea grain initiative jcc has established a route for vessels inbound and outbound of ukrainan ports → - HYDROLANT 1980/22 · Other · Black Sea2022-08-09
…MILES WIDE. WHEN TRANSITING THE MARITIME HUMANITARIAN CORRIDOR, VESSELS ARE CONSIDERED RESTRICTED IN THEIR ABILITY TO MANEUVER. VESSELS MUST TRANSIT 0200Z TO 1800Z DAILY. 3. A SOUTHERN WAITING AREA IS…
The maritime humanitarian corridor is open for outbound and inbound vessels until further notice → - HYDROLANT 1964/22 · Other · Black Sea2022-08-07
…MILES WIDE. WHEN TRANSITING THE MARITIME HUMANITARIAN CORRIDOR VESSELS, ARE CONSIDERED RESTRICTED IN THEIR ABILITY TO MANEUVER. VESSELS MUST TRANSIT 0200Z TO 1800Z DAILY. 3. A SOUTHERN WAITING AREA IS…
The maritime humanitarian corridor is open for outbound and inbound vessels until further notice → - HYDROPAC 1401/02 · Debris · Yellow Sea2002-07-31
…MARINERS AND AIRMEN ARE WARNED THAT VESSELS INVOLVED IN SALVAGE ACTIVITY WILL BE RESTRICTED IN THEIR ABILITY TO MANEUVER. 2. OPERATIONS MAY INCLUDE TOWING OF SUBMERGED OBJECTS AND EQUIPMENT TETHERED FROM…
The united nations command in seoul, republic of korea, announces military salvage operations 041501Z aug… → - HYDROLANT 1313/99 · Derelicts · English Channel1999-06-25
…51-05N 002-33E. 3. VESSELS NOT UNDER COMMAND, ANCHORED IN TRAFFIC SEPARATION SCHEME, RESTRICTED IN THEIR ABILITY TO MANEUVER, OR WITH DEFECTIVE NAVAIDS ARE ALSO REQUIRED TO REPORT.
Mariners are advised of a mandatory reporting system, "caldovrep", which goes into effect at 010001Z july →
Often in the same message
Related terms
- Underwater operations
- Divers or remotely operated vehicles are working below a vessel that cannot easily move out of the way.
- Cable operations
- A ship is laying, burying or repairing a submarine cable, usually along a stated route.
- Dredging
- A dredger is deepening a channel or moving sediment, often with floating or submerged pipelines to the shore.
- Tow / towing
- A vessel towing another vessel, a barge or a structure — slow, hard to manoeuvre, and with a long line between.
Counts cover the messages in this archive that use the term, recounted 2026-09-24; see coverage for what is collected and since when. Not for navigation — follow official NAVAREA and coastal broadcasts.