Top Pilotage Tips: How to Master Navigation in a Sea of Tech
Sailors can easily get distracted by their phones, iPads and chartplotters. Rod Heikell explains why pilotage is still important in this digital age.
It is something of a meme to depict a society going about their lives gazing raptly at a smartphone and not at the world around them. Mind you, in my experience it is closer to reality than the jokey depictions on social media might suggest. So it should come as no surprise that gazing at a screen has become the norm on yachts and for many the singular tool for navigation in strange waters. On Skylax we are not Luddites but choose to respect the warning when firing up the chart plotter or any digital device used for plotting that advises that ‘the device is an aid to navigation’.
When I first sailed Roulette to the Mediterranean, I was woefully under equipped even for the 1970s. On board was a grid-bearing main compass, a hand-bearing compass, a lead-line and charts and pilots. You might think I was being irresponsible, and maybe I was, but I did take Roulette safely from the UK to Greece when some better equipped yachts did not make it. Over the years, the development of navigation instruments and techniques has changed out of all recognition and now all of us have LCD displays lighting up the navigation area and in the cockpit. Through this lightning-fast evolution, from an EP of doubtful value to a GPS position to two or three decimal places, I always remember the advice from a well-travelled Frenchman I met who told me to ‘always use my nose’. Whether you are arriving somewhere for the first or the 20th time, it is vital that you sniff out the situation and look around you.
What those early days taught us was pilotage skills that are still useful today. The best equipment for navigation is not the hardware down below and in the cockpit, but the ‘wetware’ between your ears. It can perform incredibly complicated algorithms from diverse data and will frequently be the only thing keeping you safe when the digital readout says everything is apparently fine. Too often, yachtsmen charge on blithely past dangers to navigation and towards a new harbour, trusting implicitly that the LCD readout will take them safely there when, in actual fact, they should slow down, stop and look around, and then proceed cautiously using le nez to sniff out dangers and act accordingly if it doesn’t feel right.
How accurate is your chart?
You might think that the chart on your plotter or digital device is a brand-new, up-to-date chart. Think again. Most charts for the Mediterranean and elsewhere were surveyed in the 19th century using astronomical methods to determine positions, and old-fashioned triangulation surveying to get the shape of things. Many of these charts used obscure datum sources and, in many cases, the datum is not known at all. The charts are a triumph over the method with often outstanding accuracy in the face of adversity. Admiral Beaufort was shot and dangerously wounded in Turkey while surveying. Nelson surveyed places like La Maddalena on the north of Sardinia while hunting Napoleon. Over the years these surveys have been updated and improved upon, but it is important to remember that most of the original surveying for the charts we use was carried out in the 19th century. Most modern surveying touches upon bits of coast or around commercial harbours and covers those sea areas used by commercial ships. Very little of the sea areas outside commercial hubs has been recently surveyed.
What is needed is for the world to be resurveyed using satellite pictures so charts agree exactly with WGS84 GPS datum; but in this cash-strapped world where the ‘market forces’ determine most of what happens, this is unlikely and we are left with our 19th-century charts re jigged to agree with WGS84 as best can be managed. In places it is happening. In 2008 I was in Neiafu in Tonga when the New Zealand surveying ship was there doing the first survey since HMS Penguin in the 1890s. Many parts of the world have not been as fortunate to be recently surveyed and while cartographic departments get closer to the real world, we are not quite there yet.
The discrepancies between a GPS position and the charts that the positions are plotted on can lead to some disastrous results. You would hope that users would get a bit of a clue when they find that their charted position when anchored, or rounding a headland, shows them on the chart trundling across the land. This discrepancy exists precisely because the GPS position is accurate, but there is no chart accurate enough to plot the position on.
Apart from chart plotters, smartphones and tablets are often used for electronic navigation and the same caveats apply to them as well as chart plotters. They will be running the same electronic charts with the same deficiencies as a plotter though at least they are usually cheaper to update than the fixed chart plotter.
A few old fashioned skills
With the ability to insert a waypoint and then watch your yacht glide across the screen of the plotter to the waypoint, it might seem as if old fashioned navigation and pilotage skills can be thrown overboard. It all seems so easy and so alluring. There are a lot of reasons why not to throw out all those old fashioned skills and here are a few reasons why old fashioned skills and pilotage might save your bacon and your boat.
l Researching where you are going to and how you are going to get there is a whole adventure in itself and it lays the basis for a more relaxed and enjoyable passage. That doesn’t mean you aren’t going to worry about stuff on passage, just that you have a better knowledge of what to do and how to carry it out. A bit of research gives you a mental map of what to look for when you enter an anchorage or a harbour and, moreover, time to look around you. Mostly this involves sitting down with paper charts and pilots or the internet and going over the overall passage plan intended and over the tricky bits. The tricky bits mostly have to do with the hard bits along the way and the approaches to them.
l Part of that research used to be the old fashioned concept of looking for a port of refuge should things not pan out in the anchorage or harbour you have initially chosen. Having an alternative in mind gives least some peace of mind. If you are in an anchorage or harbour that becomes untenable with unexpected strong winds, then it is a good idea to have an idea of an alternative that will be safe in that weather.
l Have someone up on the bows keeping a visual watch when you come into an anchorage or a harbour. Use hand signals for the helmsman to slow down, turn to port or starboard and, just in case, to reverse with power. I often see boats coming into an anchorage with everyone in the cockpit and driving straight up on a reef that is charted and obvious to someone on the bows. This year I watched a 46 footer coming into Poros with the helmsman sitting down behind the wheel. It left the buoyed channel and smashed into a 4m high rocky reef that is clearly visible. People dashed out from down below and the yacht bounced off again before heading into the channel. Helmsman busy checking his social media?
l With someone up front guiding you into an anchorage, the person on the bows can look at the sea bottom to see where there are nice sandy spots or weed free places to drop an anchor. In coral they will be looking out for bombies, coral heads, to avoid and keep clear of when anchoring. In our eco-age it is important that we keep clear of Posidonia, sea grass in places like the Mediterranean and avoid damaging coral in tropical anchorages.
l Apropos the caution above on chart accuracy, leave a safe distance off dangers to navigation such as isolated reefs or reefs running out from a headland. Electronic vector charts will often not show reefs or other underwater obstacles until you zoom right in on the sea area where they are located. For Vestas Wind and others, this glitch proved calamitous. In Nukualofa in Tonga everyone was worried about the passage out of the Tropics into the higher latitudes around New Zealand. In the bar I asked if anyone was thinking of stopping at Minerva Reef. A couple said they were, but several skippers asked me where Minerva Reef was. It sits on the rhumb line to New Zealand and it soon became obvious to me that these guys were using electronic charts to plot the passage. Tiny little Minerva Reef doesn’t show up until you have zoomed right into it… assuming you knew where it was in the first place. On the passage chart there is at least a black dot with ‘Minerva Reef’ next to it.
l You will need some sort of back-up if your plotter or smartphone or tablet expires for some reason. Crossing the Atlantic from west to east our brand-new plotter died and despite trying everything it was as dead as a dead thing. Fortunately, we had a handheld GPS with a 12 volt lead that Lu positioned above the hatch in an old yoghurt pot with the front cut out so that we could see it from the helm. We keep a three hour log anyway so the lat and long were marked on a chart and away we went. The company gave me a new plotter in Gibraltar which is fine but isn’t going to happen mid-Atlantic.
l Vector charts are digitised versions of charts so they are seamless as opposed to raster charts which are scanned copies of the chart. Often you will not see dangers to navigation like reefs or islets unless you zoom in on a vector chart. Always plan longer passages on a paper chart. Chart plotters and charts on other electronic devices will not show rocks, reefs and even small islands until you get down to around 1:150,000 or even 1:100,000.
Polarised Sunglasses
Polarised plastic is known as a dichromic material and it transmits light only in one plane, typically the vertical. By cutting out the horizontal plane, polarised sunglasses effectively remove one plane of the reflected light on the surface of the sea; this allows us to see transmitted light bouncing off shallow areas such as reefs and sandy bottoms. These are the light blue, green and turquoise colours that identify underwater obstacles. The value of polarised lenses in detecting just where a reef is and where the sandy patch is to drop anchor should not be underestimated and normal sunglasses are not good enough. Here are some general rules for wearers of polarised sunglasses.
Deep blue: 15m plus
Turquoise: 10m
Green: 5m
Brown: you can identify marine species
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