Following two separate high-profile collisions of USN destroyers in the Asia-Pacific, there has been a host of theories and questions regarding how these tie in together. This post is not an attempt at determining the cause of the collisions, but rather a general comment on similarities and factors differing between the USS Fitzgerald (DDG 62)/ACX Crystal and USS John S. McCain (DDG 56)/Alnic MC collisions, and some of theories thrown around. I won’t provide any conclusions, but rather ‘Food for thought’, as my high-school teacher would have put it.

To begin with, both destroyers are of the same Flight I sub-variant of the Arleigh Burke-class destroyers, which make up roughly the first third of the destroyers produced in the series. Both were operating in the western parts of the Pacific when being hit by civilian vessels in the side. There are however important differences as well.

• USS Fitzgerald was hit in the starboard side, while sailing somewhat south of the main sea lane leading into the Bay of Tokyo from the west,
• USS John S. McCain was hit in the port side, while roughly at the eastern entrance of the Singapore Strait.

While the waters around Japan are far from deserted, they still pale in comparison to how busy the seas around Singapore are.

When discussing collisions at sea, it is important to understand one basic difference between maritime traffic and the rules of the roads: as long as as you have water under the keel, you are more or less allowed to go anywhere you want. As there are no road signs or traffic lights, issues such as right of way are instead dependent on the position of vessels relative to one another. These guidelines are found in an international document entitled ‘Convention on the International Regulations for Preventing Collisions at Sea, 1972‘, though understandably it is usually referred to by its abbreviation: COLREG (or COLREGs).

The most basic of the rules are that a ship coming from starboard (right) has the right of way, and a ship coming from port (left) has to give way. If two vessels meet head-on, both will generally hold to starboard (i.e. the seas feature right-hand traffic), though there are also a number of readily available signals which can be used to tell a nearby vessel that you will pass on their port side.

As such, a first thought is that the USS Fitzgerald would have had to give way to the ACX Crystal, while the Alnic MC would need to give way to the USS John S. McCain. However, it needs to be remembered that large ships take considerable time to turn or bring to a halt. For the collisions discussed here, it should be remembered that the destroyers are considerably more nimble than large container ships and tankers. There’s no cutting in front of a tanker just because you in theory have the right of way!

For the USS John S. McCain/Alnic MC-collision, the Singapore Strait feature a traffic separation area which adds another factor into the equation. This can be described as a highway of the sea, where westbound traffic all flow in a northern lane, with eastbound flowing in a southern lane, and in between there is a off-limits separation zone (virtual roundabouts allows vessels to enter ports in the area). These are found in other narrow areas with relatively heavy shipping as well, including the Gulf of Finland. The collision seems to have taken place just at the entrance to the traffic separation area. It is possible that these special arrangements would have caused one of the vessels to make unexpected course adjustments, or that a third vessel did something which caught the attention of the bridge watch to the extent that they did not notice the more immediate danger.

There has been a number of speculations in that there would be foul-play such as GPS-spoofing or hacking of key systems would have caused the accidents. However, as described above the COLREG does not depend on the position of your vessel, nor does it allow the bridge watch to depend upon systems such as AIS for watchkeeping. Regardless of if some of these were out of order, the watch need to observe the position of the other vessels around it and react accordingly (i.e. keep a safe distance and give way to vessels according to relevant rules). Even if something was hacked or the GPS was out of order, and to my understanding there is no indication of this being the case, this should not cause a collision in and by itself.

There has also been claims that the McCain would have temporarily lost steering, only to regain it later. This could be a number of issues, ranging from running into something physically obstructing the movements of the rudder, to something being wrong with the equipment operated by the helmsman, or anything in between the two. It is also unclear to me what exactly the ‘loss of steering’ include. For warships, there are usually multiple steering stations and some kind of last-ditch emergency steering which overrides any steering commands from the helm stations. However, if the loss of steering was only temporary, it might be that there were no time to initiate emergency steering procedures. It is also not uncommon for sudden and unexplained steering issues to eventually be traced back to the helmsman not fully understanding the workings of the system, e.g. how to properly switch between autopilot and manual control.

This brings us back to an issue which has been raised, and which I believe might very well explain the issues at play. The US 7th Fleet is severely overworked, with no time being allocated for training in the deployment schedule of the destroyers and cruisers. This in turn means that much of the training is handled while on deployment, with the older crew members likely overseeing younger ones during time they otherwise would be off-duty. In the end, this likely leads to the crew as a whole being less rested. The background to this is obviously the lack of any frigates or corvettes in the US Navy, meaning that the destroyers and cruisers has to do a host of tasks which they are overqualified for, and with tensions with China increasing the need for qualified ships are going up as well. The LCS-project was meant to solve part of this issue, providing a light ship for patrol and flag-waving duties were a destroyer isn’t needed, but as is well-known this has run into problems and delays.