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In the third instalment of our Sea Signs series William uncovers the huge amount of information you can gather by simply looking at the boats around you.

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When I travel somewhere new one of the first things I do is carry out a detailed study of the local boats. It tells me a lot; it tells me whether the coastline is exposed to powerful ocean swell or protected from it, if the tide goes a long way up or a long way out, if the water stays shallow or gets deep quickly. Boats tell me what fish are caught locally and what the socio-economic demographics of the community are. Perhaps most importantly, the shininess of the boats in the marina tells me if I’ll be able to afford lunch in the waterfront restaurant or if we should stick to a picnic in the cockpit.


One of the best ways to gauge the nature of the surrounding coast is to look at the local lifeboat; it should be perfectly adapted to the environment it operates in. Lifeboat stations with hovercrafts indicate expansive mudflats [look out for quicksand] where the tide goes a long way out, then races in fast. In contrast, when you see stations with lightweight inshore rescue craft you should get your surfboard ready because these boats are perfectly suited to zipping around high-energy surf beaches and rescuing people from powerful rip currents [we’ll explore these next month].

Fishing boats hauled up on the beach are almost always left above the highest Spring Tide and you can be fairly confident that anything above here will stay dry. This small tit-bit of knowledge can guarantee unadulterated relaxation; by setting up your beach towel above this point you can doze away the afternoon safe in the knowledge you’re not going to get rudely awoken by the flood tide lapping at your toes. It also saves the stress of having to move your picnic; last summer I walked past a group in Margate consisting of three families with three young children apiece scrambling their culinary delights to higher ground before the tide washed it all away. I considered giving them a flyer for my Tide Walks but the serious looks on their faces warned me it might not have gone down too well.



When a boat gets into the water it can tell you a huge amount about the wind, waves and currents – even what creatures are in the water. On a recent trip to the West Coast of Scotland we were meandering along a winding road high above the water when I spotted a boat slow down and come to a stop far below, rocking gently in the swell. I pulled over and scanned the waters around the boat for fins. The clue to what I was looking for was emblazoned in thick white text on the navy blue hull; WHALEWATCHING. Although there was no whale, the commotion on-board was for a magnificent Sea Eagle circling the boat.

“when a boat is in the water it can tell you a huge amount about the wind, waves and currents”

Not all vessels give away their intentions so clearly as those branded WHALEWATCHING. Sometimes you have to work it out by deciphering a sequence of balls, cones and cylinders, or brightly coloured flags, or by counting the number of bursts on a horn. This complex set of communications is known as the International Code of Signals and if you’re having adventures along the coast it can be useful to learn. There’s a lot to remember so I’d start with the essentials; three balls in a crucifix means “I am clearing mines, stay 1,000 metres away”, a red and white chequered flag means “you are heading towards danger”, and if a boat blasts its horn at you five times it means they have absolutely no idea what you are doing or saying. If you see a boat hoist a white flag with a red X it means “I need assistance” and the responsible action would be to call 999 and ask for the Coastguard.


A boat at anchor displays a single ball. This is useful to remember because boats at anchor almost always face into the current. On most boats the anchor is attached by a single rope to the bow [front] and the currents will swing the vessel around so they flow evenly on either side of the hull and the boat faces directly into the stream. This phenomena is fascinating during Slack Water when the currents change direction because you can see the boat swinging around on it’s anchor. This tells you to expect the currents to flow that way for the next six hours, speeding up for three hours then slowing down for three hours. 

BOAT AT ANCHOR [Credit William Thomson].

One of my favourite views along the coast is a sailing boat on the horizon, its sails set far out either side, the white canvas glowing golden in the sunlight while its multi-coloured spinnaker billows ahead. This sail configuration, reminiscent of a proud peacock and called the ‘goose-wing’, provides some valuable information – it tells you the boat is sailing downwind. In contrast, when the spinnaker is stowed away and the sails are pulled in tight the boat is sailing upwind, a technique called ‘close-hauled’ where the sail configuration maximises its aerodynamic qualities and literally sucks the boat towards the wind.  You may notice that the wind on the beach is different to what the boat is telling you; this is because coastal structures like buildings, trees and cliffs often funnel and eddy the wind, masking its true direction and strength. By observing sails at sea you’ll know the ‘true wind’ and be prepared for it when you get out on the water. 


Whether a boat is sailing, anchoring or motoring, its motion can give you an idea of how big the swell is. When I was surfing in Northumberland during my university years there was often a tanker just offshore, waiting to go into the River Tyne. One day I was watching it and noticed the boat suddenly rock wildly from side to side. Soon after a set of huge waves arrived at the beach and I got tumble-dried – a process that closely resembles being tossed around in a washing machine. The next time I spotted the boat rocking I made use of my new early warning system and paddled out to the deeper water where bigger waves break. I was the first there and that meant I was the first to catch the wave and in the world of surfing that means it’s ‘your’ wave. Observing that boat not only gave me a competitive edge over the other surfers; the adrenaline from riding those waves kept we warm and energised through cold and dark winter sessions. So keep your eyes peeled for the boats around you; you never know what the reward will be.

In the next Sea Signs feature William will explain the symbiotic relationship between waves and rip currents.

About this series

Every day the sea is different, a  result of the ever-changing interaction between the moon, sun, tides, wind, waves,  buoys, boats and the beach. While the picture may appear complex, like a piece of classical music, it is essentially just an arrangement of simple elements, or notes. By dismantling the machine into its component parts and exploring each one in detail we can create order out of chaos; clarity out of confusion. That is the  purpose of this series 'Sea Signs'.

When we are young we learn to navigate urban environments; what traffic lights  mean or how to cross a road. What many of us aren’t taught is how to read nature’s  signposts; how to judge wind by watching birds or what weather different clouds  bring. Then there’s a whole technical world of buoys and boats with different light  sequences, colours and signals communicating messages. My goal in this series is to  share with you all the signs – both natural and man-made - that you may encounter in  your adventures along the coast so you can read them as well as any yachtmaster  skipper or crusty old seadog. 

With this knowledge, nothing is going to slip under your radar.

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