Twelve years ago, about this time of the year, I was charging down a sea lane in the outer archipelago as the helmsman and engineer of a Jurmo-class landing craft. On my left side one of my fellow conscripts sat and focused on navigating, as he was working as the skipper of the vessel that day. Both of us were also keeping a lookout around the vessel. We had both received the same training, allowing to us serve as helmsman/engineer or as the skipper/navigator of the Jurmo, and when out on longer exercises we usually rotated between positions every other day. Following a sharp left-hand turn which took us straight towards an island I spotted a Pansio-class mineferry. Just before the island we were headed towards we would turn sharply to the right, and the large vessel now sat directly at the turning point, in front of the island. As we got closer, I noticed that it seemed like the skipper might not have noticed the mineferry, so a couple of hundred meters out, with plenty enough time for us to take the turn safely, I drew his attention to the vessel and asked how close he wanted to go. “Oh fuck, I did not see that one coming,” he said. “Helm to the right.” I acknowledged the ordered and we used the fact that we had plenty of water under the keel to our advantage to cut the corner slightly to maintain a safe distance without having to slow down for the passage.

Just over eight years ago, I was on my first ‘real’ job in the maritime industry working the summer at local boatyard Kewatec Aluboat. Much of the job revolved around the Pilot 1500-class of fast pilot vessels which were just being finished and delivered to the Finnish pilotage service Finnpilot Pilotage Oy. Despite being a green mechanical engineer roughly halfway through university I got to do some fairly interesting stuff, such as riding along on the sea trials to keep book on results such as RPM relative to speed and noise level measurements. Eventually Kewatec would be my first full-time employer, and I spent a few really interesting years there before moving on to what was then Rolls-Royce’s waterjet division (now Kongsberg Maritime Finland).

Both of these experiences came vividly back when I last week got a Twitter DM with the Finnish Safety Investigation Authority’s report on an incident where the Pilot 1500-class fast pilot vessel L239 had come close to colliding with the Hamina-class fast attack craft Hanko last December. Out of curiosity I did a quick glance through the abstract of the report, and might have left it at that if it wasn’t for the fact that the newspaper headlines that came out of Finnish daily Turun Sanomat over the next days didn’t square with the impression I had been left with.

In fact, the report does not lay the blame on the lack of AIS on the part of the Hanko. Nor is AIS some kind of magic safety beacon. But let’s start from the beginning.

In the early hours of 1 December 2018 Hanko was transiting southwards in the Sköldvik sea lane. The weather and visibility was generally good (considering it was pitch-black with clouds), but the wind was near gale at an average speed of 16 m/s (note that in the narrow waters this meant a wave height of 2.4 meters). At the same time, L239 left Emäsalo pilot station and entered the same lane heading north. Hanko picked up the vessel as soon as she left port, and started tracking her using normal procedures. Notably, Hanko that had been steaming down the lane to the left of the midline (her left) altered course slightly to get over to the right side of the lane to allow for a standard passing where both vessels hold to starboard (i.e. right-hand traffic as is the international standard on the seas). Hanko, in accordance with standard procedures of the Finnish Navy, did not have her AIS switched on, but had reported her general area of operating to the local Vessel Traffic Service (VTS), which informed the pilot vessel that a naval vessel was operating in the area. L239 did however not spot the Hanko when she left port, and a radar echo of the vessel was dismissed as a flock of birds.

The route was a standard run for the L239, and when the lane was empty the pilot vessels usually took the shortest (and somewhat more sheltered) route in the interest of saving time and fuel. This put the pilot vessel well to the left of the middle line, i.e. heading straight for the Hanko. While Hanko was cruising at a moderate speed of about ten knots, the L239 was doing close to 25 knots with the wind at its back. A few minutes later the crew on the bridge of the Hanko realised that the pilot vessel hadn’t noticed them and immediately stopped (as the vessel is equipped with waterjets, it is able to quickly stop even from a considerable speed). At the same time the skipper of the pilot vessel noticed something in front of him, and turned on the spotlight. This showed an unidentified vessel right in their course, so he quickly reduced speed and turned right towards the midline of the sea lane. The two vessels passed each other at approximately 40 meters distance. The whole incident had taken place in less than seven minutes from L239 leaving the port.

Here we’ll take a short interlude to discuss what AIS is and isn’t. AIS is an automatic transponder system that sends data over the normal VHF-band. This usually include the vessel’s name, position, heading/course, speed, and potentially a number of other pieces of information (turn rate, heel, destination, ETA, current mode of operation, …). On the positive side it is inexpensive, simple, and when combined with other systems such as radars and chart plotters it provide a situational picture that is easy to read and interpret. It is mandatory equipment for a number of vessels, including merchant and passenger vessels. Crucially, it is not mandatory for neither pilot vessels nor for naval vessels.

AIS has been in the headlines a number of times in recent years, including its role in the collisions of Norwegian frigate KNMS Helge Ingstad and the two US Navy destroyers that collided in separate incidents in the Pacific in 2017. However, it is crucial to note that not only is AIS susceptible to spoofing, it can also simply be switched off at the flick of a button. In Finnish waters, as opposed to out on the high seas is the majority of vessels moving around are not fitted with AIS due to their small size. Pleasure crafts might not be moving around in the Sköldvik area in the middle of the night in two meter high waves in December in any huge numbers, but there’s always the risk that some local is heading out to check on his summer cottage. As such, AIS is not God-mode view on a bridge display, but just another (very good) source of information to build up situational awareness. As a matter of fact, navigating solely on electronic aids such as AIS, or radar for that matter, is not allowed under international rules, as all vessels are required to keep a proper lookout.

Going back to my opening story from 2007, there were a few issues that could have led to it ending badly. The first was that we were under a tight schedule. We were part of an exercise scenario with several moving parts, and it was crucial that our vessel were at the designated point at the designated time. The second issue was that the timing of us and the Pansio-class crossing paths was very unfortunate, with it coming from an unexpected angle and with our vessel turning towards it at a time window measured in mere minutes when it wasn’t silhouetted against the horizon but completely in front of an island. The vessel, like the Hamina-class, is also painted to easily hide in the archipelago, and the colours work extremely well. However, the Navy doesn’t just throw enlisted conscripts into a fifteen meter vessel with a thousands horsepowers to work with and see what happens. There are clear cut roles and procedures to follow to ensure safe operations, and before one gets to sign the line next to the word “Skipper” in the logbook there’s a number of steps and certifications that you need to meet.

As mentioned, these procedures include that both crewmembers keep a lookout. The reason is simple: the skipper will need to keep one eye on the navigation, including the paper chart, chart plotter, and the radar, while the helmsman will need to keep one eye on the engine instruments. If something starts to go ever so slightly off the rails, it is easy for either crew member to be distracted and spend too little time looking out the windows, and as mr. Murphy dictates, that always happens at the worst possible time. As such, having both crew members keep their eyes open is a necessity. In our case, the training showed its worth, and the situation was solved safely and without incident.

As such, reading the report, the most baffling detail for me personally is that the pilot vessel always operate with two certified skippers aboard, of which one function as the vessel crew and the other is the safety guy when the pilot is transiting between the vessel and the ship. This isn’t baffling in itself, but the safety guy has no duties whatsoever while the vessel is underway, not even a general recommendation to keep looking out the windows! While the vessel is built to be able to be operated by a single crew member, not using the available resources is a strange decision to say the least.

The Hanko on the other hand was naturally operating with a significantly larger crew. The persons on the bridge included not only an officer of the watch, but also a navigator, a assistant navigator, and a dedicated lookout working outside of the vessel. As noted, the crew noticed the L239 as soon as it put out to sea, and assumed that the pilot vessel had noticed them in turn.

This was likely the single largest shortcoming on the part of the crew of the Hanko. Having a very good situational awareness thanks to good working procedures, it’s easy to start assuming this is how all professionals at sea operates. Giving a short radio call to the L239 to confirm that Hanko switches from left to right side of the sea lane for a standard meeting would have ensured that both vessels knew of each other’s presence. Hindsight 20/20, as they say.

However, the actions of the pilot vessel is harder to explain. The skipper knew that there was a naval vessel in the area but apparently did not try to locate it. There doesn’t seem to have been any discussion that the safety man would assist in keeping a lookout, nor any decision to slow down or keep in the correct part of the lane in case someone else was moving in the night. Granted the Pilot 1500 series is well-equipped to be handled by a single crew member, it sports two large displays for the radar and the chart plotter placed in front of the skipper to allow for a minimum of head movement when switching between checking them and looking out the windows. However, the rule (both written and unwritten) is that electronic aids support looking out the windows, not the other way around. This is especially true in cases where getting a clean radar picture is difficult, such as in rain or rough waves, where one easily end up either getting the screen overtly cluttered or filtering away real echos. While the report doesn’t mention it, the fact that such as large radar target as the Hanko was mistaken for a flock of birds does indicate that the radar didn’t provide a good and easy to read radar picture at the time of the incident.

Stealth interlude: Yes, Hanko feature signature reduction measures, but it isn’t invisible to radar by any stretch of imagination. In a later reconstruction the pilot vessel’s radar was able to pick up the FAC well beyond two nautical miles (beyond 3,700 meters), the VTS also got a clear radar echo of the vessel, despite the tracking algorithm having some issues tracking Hanko correctly at the time of the incident.

The report by the authorities notes five conclusions, of which two are related to the reporting processes for incidents and accidents on a national level. The three others are:

1. The tracking of non-AIS transmitting vessels require use of radar and particular care by the VTS-operators,
2. The resources of the pilot vessel were not used optimally considering the conditions,
3. The crew aboard vessels that try to avoid detection don’t necessarily recognise the risks this create.

In other words, the report does not blame the Hanko, nor the lack of transmitting AIS on it’s part. The standard procedure of the Finnish Navy is to have the AIS turned off due to operational security considerations. Navies around the world have varied views on the use of AIS, with some having it always off, some having it on without IDs, and some having it on close to shore but off when at sea. Steffan Watkins has a good overview, but as usual things are different between the Atlantic and the Gulf of Finland.

A key difference is that Finnish vessels don’t transit. The operating area often starts when the quay is left behind. Another is that the Finnish Navy uses dispersed and wartime infrastructure, which you don’t necessarily want to show on the internet. And while fixed infrastructure likely is known to the adversary, the usage isn’t as easy to judge considering the concealed nature of the archipelago. Space based sensors are one possibility, but they don’t either provide the kind of continuous tracking that AIS creates. Switching it on and off also degrades OPSEC, as it shows when and where a mission has started. Just as when observing a black hole, you can glean things from observing what isn’t there in the same way as observing what actually is visible.

Without having insight in the finer details of how the Finnish Navy bridge crew works, I find it plausible that the report might have a point in that the risks of not being noticed might be underestimated and deserve more attention. However, as the Navy will never be able to maintain OPSEC and spend significant time with the AIS active, the way forward for the Navy is likely to be a bit more proactive with hailing approaching vessels on the VHF and using lights more liberally, as there always will be people on the seas that aren’t quite alert enough.

Another important detail is that as mentioned, in the archipelago as opposed to out on the Atlantic Ocean one can’t assume that all vessels in the area are of the size that they are equipped with AIS. Granted, the pleasure craft traffic is concentrated to good weather days in July, but there’s always the village fanatic who is out with his nets regardless of time of the year and weather. And if you keep a good enough lookout and have adjusted your speed appropriately that you will spot someone kayaking in time to take evasive actions, you will spot a Hamina-class vessel as well, AIS or not.