June 13, 2009
Losing the Plot
The determination of risk of collision is a basic navigational skill. Equally basic at sea is situational awareness and the ability to keep track of dozens of vessels in congested waters, including oftentimes numerous fishing vessels and to interpret information, all in real time. This is bread and butter stuff; a watchkeeper who cannot master this, and be right all the time, is simply unfit to keep independent watch.
It is therefore dismaying that this basic skill is found wanting in more than a few navigating officers at sea today.
To be fair to present day watchkeepers, there are some contributing factors at play here: Short manning, an explosion in tonnage at sea over the last few decades, hugely increased instrumentation and electronics requiring sporadic and diverting attention, an increase in VHF reporting and, sometimes, the location of at least part of commercial communication equipment on the bridge are some. All these require the watchkeeper to multitask to an astonishing degree. In addition, lookouts, even if available, may be unreliable or otherwise occupied.
However, all this does not fully explain lower standards. Paradoxically, a watchkeeping officer is required to be more efficient today because of these very reasons. He is also more likely to be in charge of an independent watch in congested areas: areas in which a Master may have been on the bridge twenty years ago but now is transitting trying to get some sleep in his cabin. Those of us who have been on short sea trades in the North Sea or the Malacca Straits know this very well.
It is my contention, therefore, that we must train officers sufficiently, and even overtrain them, to ensure that they can handle navigational watchkeeping with an acceptable level of safety. The industry has assumed that experience at sea along with the attendance of a few questionable training programmes ashore is the panacea for this problem. Masters who sail will tell you that the reliability of at least one of the three watchkeeping officers on the bridge is often suspect; in fact, many consider it a bonus if both the other two are good.
The first thing we must do, in my opinion, is to make simulator based examinations part of the Certificates of Competency at every exam. The simulations must be utterly realistic, conducted for highly congested waters with strong currents, and must, in addition, ‘stress test’ the officer. This examination must also have the most stringent standards and the highest passing percentage requirements.
Some other factors which need to be addressed include fatigue, location of unnecessary communication and other equipment on the bridge, ergonomics of the bridge layout including ensuring all round visibility and the banning of ‘paperwork’ during bridge watches. Some of these are in the Master’s domain, while others are not likely to be fixed during my lifetime, at least. Meanwhile, given that acceptability of an officer’s calibre is often dependent on the competence of the general pool available out there, a Master must usually sail with the officers he gets. So how does he augment navigational safety without holding classes to reinvent the wheel?
With respect to the issue of the determination of risk of collision as well as collision avoidance, I have found the following useful:
• Push navigating officers to make a habit of keeping a proper lookout. I have lost count of the number of times I have come up on the bridge and seen, at close quarters, a fishing boat or sailing vessel (and sometimes larger ships) in good visibility and bad; vessels of which the officer on watch is unaware. This is mainly because he has been using the radar (usually on long range) as his lookout instead of his eyes.
• Push officers to realise that the change in a rough visual ‘bearing’, taken from a fixed point within the wheelhouse, is sometimes good enough to determine if any risk of collision is likely to exist. This beats running to the radar every few minutes and playing computer games there for each target. It also helps in keeping a good lookout.
• The track drawn on the chart is a guideline, not the line that Lakshman drew for Sita in the epic Ramayan. Do not hesitate to go off course for safety, and do not be in a hurry to bring the ship back ‘on the line’ before you hand over watch.
• Ships can hit us from behind, too. Keep an eye out.
• Make them understand that the AIS and the VHF are not primary (or even secondary) collision avoidance tools. Again, lost count of officers reading off CPA from the AIS or making a VHF call of ‘ship on my starboard bow’ in the English Channel in restricted visibility.
• Push officers to understand the characteristics of the Radar and ARPA completely. Special stress on blind and shadow sectors, inputs from other equipment like GPS and Gyro, use of controls and unique features, including quirks and issues with target swap. And, if intelligence permits, the use of ground and sea stablilisation.
• Special attention to anti sea clutter, anti rain clutter and gain. Don’t laugh; you would be surprised how many times targets are not seen because officers do not set these controls properly, or know enough to use optimum settings for the equipment, especially in poor visibility.
• Explain the use of appropriate scale on the radar, as well as the offset function. Used judiciously, these are good tools for enhancing target visibility. A six mile range with a 25 percent offset is often better than a 12 mile centred range in dense traffic.
• Make Parallel indexing standard operating practice. Although not a collision avoidance measure in itself, PI can tell you quickly where you are in respect to your course line and where more sea room lies when close to land. It also reduces the tendency to plot positions too often, and so leaves more time for collision avoidance.
• As far as possible and available, automatic acquisition of targets to be set on the ARPA. Again, this ensures that time spent playing ‘computer games’ is reduced. (See trails below)
• No guard zones. Unreliable, especially in bad weather and with small targets, and lull you into complacency.
• If intelligence permits, explain the use of Trial Manoeuvres.
A feature very common on modern marine radars that I find especially useful is the ‘trails’ function. Briefly, for those who may not know, this consists of a true or relative (depending on operator setting) ‘tail’ behind each target, and is usually in a distinctive colour. The length of the trail is dependent on time (again, operator setting). Most importantly, the direction of the trail gives you, at a glance, the true or relative motion of the target during the time period set.
I usually set the trails to automatic (all targets, including land, are trailed) and relative, with an appropriate and short time interval rarely exceeding 3 minutes. That is all one has to do, once every watch. Henceforth, anything the radar picks up will be trailed. Trails which are parallel or angling away from you can be ignored. Trails which are crossing your path may be a cause for concern. Plot or watch only those on the ARPA.
Relative trails are especially useful in large concentration of fishing vessels, where they will easily show one or two boats crossing you, while most of the others are going clear. They are also very useful generally; a quick glance is usually enough to tell you which traffic can be problematic. What’s more, a vessel altering course often shows a ‘bent tail’, and so the alteration of course becomes quickly known. Most importantly, the trail function, although no substitute for ARPA, does not require the operator to do anything once set. No time wasted acquiring targets, deleting targets and reading off superfluous information from the plot. More time available for lookout and other essential functions.
There are calculations one can do with trails, extending them and measuring CPA with the VRM and other such more esoteric calculations. I usually avoid those; I like to keep things simple.
One caveat with trails, though. Relative trails tend to clutter the screen, and are especially annoying when your own ship alters course, because bent trails appear everywhere. Therefore, the operator finds it useful, peridocially, to reset the trails (put off and on again, so the trail plot starts again). This can be more easily done by just switching momentarily to a higher or lower range on the radar, and returning to your preferred range immediately, when trails automatically start anew. Alternatively, use true trails for awhile; in any case, switching between true trails and relative trails (usually one ‘click’) gives you additional information, similar to switching between a true and relative plot.
My ideal settings for radar include no automatic plotting, no guard zones and relative trails. I will then acquire and plot only targets of interest.
Of course, all this presupposes that some time will be spent by the Master initially with each new officer who may require ‘assistance’, besides periodic monitoring of their habits. It is time well spent. On one occasion that I did not explain the trails function completely to a chief officer unfamiliar with it, the following conversation took place when I came up on the bridge to find a ship overtaking us about six cables on our starboard beam:
Me, trying an impromptu oral examination, pointing to the trail on the radar: ‘Chief, what is that?’
‘Cap, that is the seagulls behind that ship’, came the confident reply.