Eye on the Navy – Collision at sea!

Eye on the Navy

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Collision at sea!

Pay attention!  Communicate!  Go out of your way to prevent the “error chain!”


By Edward Lundquist

Senior Science Advisor

Alion Science and Technology


If incidents involving collisions at sea have something in common with each other, it is that they all could have been prevented.  With a compass full of courses to choose, only a few can put you in contact with another ship.


When two ships collide, it is usually because one – or both – did not follow the “rules of the road” – referring to the “International Regulations for Prevention of Collisions at Sea” (COLREGS).


“Groundings are almost always self-inflicted wounds but collisions usually take two or more ships making a series of mistakes at the same time and place,” says Brian Boyce, a retired Navy captain working for MarineSafety International (MSI).


Rear Adm. Dave Ramsey, U.S. Navy (Ret.), who also works for MSI, agrees.  Ramsey says that one or a combination of seven factors can lead to collisions:


1)                          Confusion:  The movements of the other ship or ships and one’s own ship are not clearly understood. Invariably, the confusion could be eliminated if the ships communicated and were clearly aware of what each other’s intentions were

2)                          Awareness:  Hard to believe, but in the USS Arthur W. Radford mishap, the Arthur W. Radford was not aware of the other ship until too late.

3)                          Distraction:  The watch is not attentive because of other tasks or not focusing on standing the watch.

4)                          Poor organization:  Watch team duties are not clearly defined or monitored by the OOD.

5)                          Policy or doctrine:  Captain’s standing orders are not understood or followed.

6)                          Shiphandling:  Many watchstanders really don’t know how to handle their own ship in a tight situation, so they turn the wrong way or fail to maneuver properly.

7)                          Knowing how to use the tools available:  Watchstanders don’t know how to use the tools available to them and, thus, don’t know which tool to believe. I’m speaking now of radar, ARPA, ECDIS, paper plots, even navigational aids.”


The common causal threads in U.S. Navy collisions is poor bridge management.  Incidents such as USS John F. Kennedy/USS Belknap, HMAS Melbourne/USS Evans, USS Collett/USS Ammen, USS Waddell/USS Brinkley Bass, all resulted from the culmination of several errors – the “error chain” – that were uninterrupted during the process, says Ramsey. 


Before designating someone as qualified to stand watch as Officer-of-the-Deck (OOD), they should have a fundamental understanding of the COLREGS.  When a new watchstander joins a ship, the commanding officer and navigator should satisfy themselves through a rigorous testing process that a new watch stander knows the COLREGS, and which rule applies in which situations.  While the COLREGS must be readily available on every bridge, and every officer standing bridge watches must know how to use them, the regulations need to be committed to memory.


“There is rarely time available to refer to COLREGS to determine which rule applies and what action should be taken,” says Ramsey.  “This is the reason that the U.S. Coast Guard requires a 90% passing grade on Rules examinations.  Good OODs will constantly be students of COLREGS.”


Capt. James A. Barber, U.S. Navy (Ret.), author of the Naval Shiphandler’s Guide, (Naval Institute Press, 2005), agrees. Few things could be worse than the OOD frantically flipping pages of the COLREGS as a potential collision situation develops.  He or she may not need to be able to recite the COLREGS verbatim, but he or she must know what they say without having to look it up.”


There are many electronic aids and computer programs available to help watchstanders determine the best course of action in meeting, passing or overtaking situations.  Some allow various maneuvers to be simulated before taking action to see which course of action is best, says Ramsey.  But mariners must know how to do this without the assistance of a computer.  The Coast Guard radar certification qualification requires licensed watchstanders to manually determine alternative courses to avoid collisions. 


“The same regulatory requirement exists when a licensed deck officer seeks certification to use automated radar plotting aids, now placed on almost all commercial ships.  The use of such electronic aids, however, means you must know how to use them.  This usage does not relieve the OOD of knowing and properly employing the rules of the road,” Ramsey says.


If a risk exists, then watchstanders on both ships must determine who is the “stand on” vessel, and who is the “give way” vessel and required to make an early and obvious course change to avoid a collision. 


Says Barber, “When maneuvering to avoid a developing situation it is important to “signal with your bow” to make clear your intentions to the other vessel.  In a meeting situation a course change of two or three degrees may be sufficient for safe clearance, but it is much better to make a ten or fifteen degree change that is clearly visible to the other vessel, then return to your course when the situation has clarified.”


Communicating with the other ship's bridge is perhaps the most important element in avoiding collisions, Barber says.  “There are multiple ways to do this.  “’Signaling with your bow’ is one way.  Whistle signals, as laid out in the COLREGS, are another.  The most prevalent means is by VHF bridge to bridge.  The person handling the communications must be familiar with the International Maritime Organization's (IMO) “Standard Marine Communication Phrases.” (See Naval Shiphandler's Guide pp.122-126.)


The rules provide for various situations, such as vessels limited in the ability to maneuver, or a meeting situation in a narrow, busy shipping channel.   Other situations exist involving naval vessels are also covered by COLREGS, including underway replenishment, or launching and recovering aircraft or boats.


Navy ships operate very close to one another when conducting underway replenishment, something merchant ships don’t do.  Even when they are in the middle of the ocean, ships conducting an “Unrep” must get within 80 to 180 feet of each other while steaming at 13 knots.  The delivering ship is the “guide,” and maintains course and speed, while the receiving ship must make an approach that brings it up and next to the guide.  If not careful, the two ships underway alongside can be “sucked together” as the pressure areas between the two ships changes. 


“Underway replenishment probably accounts for more collisions by naval vessels than any other evolution,” Barber says.  “The approach is the most hazardous part, and it is important to have multiple ways of determining separation as you make your approach.”


In 2000, a Fast Combat Support Ship (AOE) was refueling a destroyer, when the destroyer ran into the starboard side of the oiler.  “The size and hull shape of the AOE creates pressure differentials that require strict attention to the conning officer of the receiving ships. This is particularly true when the destroyer must maintain station at the forward replenishment stations where the bow wave of the AOE tends to push other ships away,” Ramsey says.


MSI’s Brian Boyce says one must understand how ships interact when alongside, as well as fundamental vector math.  In this case, the conning officer took the conn as close quarters developed and wrongly assumed that by steering his stern away from the oiler (and consequently moving his bow toward the oiler creating a converging situation) that somehow the bow pressure effects or other physics would hold his bow off.  “It didn't work.  He should have known that steering away from the oiler, even though it would place his stern temporarily closer, if done aggressively enough, would create a diverging vector that would overcome whatever was pulling the ships together,” Boyce says.


An amphibious dock landing ship (LPD) way was making an approach on a Military Sealift Command (MSC)-operated oiler in the Western Pacific, when it miscalculated its approach and ran into the oiler’s stern.  The LPD’s bow was seriously damaged.  This was caused by a series of compounded mistakes, what Boyce refers to as the “error chain.”


According to Boyce, the CO of the LPD was too personally engaged in supervising the conn to be able to objectively assess a developing dangerous situation.  “The main error was failure to assess a continuing CBDR (Constant Bearing Decreasing Range) situation.  Others saw the problem but put their trust in their captain and failed to aggressively warn him.”


Barber agrees that this is an issue.  It has always surprised me how often when investigating a collision we discover that someone in the watch team knew that a problem was developing, but because they figured the Captain/OOD/someone else knew better they didn't speak up.   Sometimes this is the Captain's own fault because he has on previous occasions intimidated people who brought him unwelcome news.”






Edward Lundquist is a retired U.S. Navy captain who is a senior science advisor for Alion Science and Technology.  Lundquist supports the U.S. Navy’s Surface Warfare Directorate.

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