Position: 49°43’07″N 2°00’14″W

Alderney Race Time and tide wait for no one. Nor do currents. Our navigation skills grew fat and lazy in the Mediterranean, at least metaphorically, and the vigorous waters around Brittany put them back on the treadmill for some intense aerobic conditioning. With no tides or currents to speak of, sailing around the Med only demands you keep a close eye on the weather. As a result we’ve been airing out the tide tables and sharpening our vector maths so we can stay off the rocks.

Here in the north, tides rush in and out, changing the water’s depth by as much as ten metres (33′) every six hours. Big tides generate strong currents around corners and capes that rage up to eight knots. Usually in the wrong direction – if you don’t plan ahead. For context, Aleta under power at a comfy 2,000 RPM, makes about six knots through the water in calm seas. Simple vector addition means in an opposing current of eight knots, we sail backwards at two knots (6 – 8 = -2).

Money in the Bank

To get anywhere, we pore over tide and current tables, and delve into cruising guides trying to figure out where to be by when. As the waters rush in and out making the sea otters and tidal pool creatures happy, we time our departures to take full advantage of the flows. A three knot current will carry us along at nine knots, saving fuel and time.

Leaving Brest at 06:00 we caught the current heading north like a couple of hobos hopping a freight train. Right through the Chenal du Four, the current stayed with us at the turn and carried us all the way to Roscoff, some 45 nautical miles away. The extra push took us there in record time.


The north coast of Brittany is reportedly beautiful with craggy outcroppings, verdant shores, and white sand beaches, all teeming with wildlife. It is a favorite destination of city dwellers from all over France. I say reportedly because we didn’t see an inch of it.

Socked in with dense fog, at times we could not see more than a couple of hundred metres ahead of the bow. Sailing by instruments makes things a little less stressful. We have radar that picks out big objects pretty well. We also have AIS which is even better at helping locate other vessels in the gloom, only with a long 30-90 second delay.

But sailboats are typically narrow and carry a small radar footprint head on. While small craft literally sail under our radar. Many small boats don’t bother with AIS either, rendering them invisible in the damp pea soup mists. We blast our automated foghorn in the hope any invisibles will kindly get the heck out of our way, but we’re in the minority there, too.

Don’t Blink

Keeping an eagle eye out forward is what we do. We keep an ear out, too, at least when Aleta’s engine is off. A couple of times boats have wandered eerily out of the mists, silently crossing our bow, to the slack-jawed confusion of the other boat’s captain. In the blink of an eye they vanish again. So fast it was at times a little disorienting.

Moisture dripped off Aleta, cleaning her of salt. She looked shiny by the time we turned into Roscoff harbour. The mists finally cleared only 30 metres from the entrance. Inside the mooring basin, the deep tide was out and the sea wall loomed large above us. But it trapped the sun and warmth and soothed our creaky joints. Checking in at reception, a couple of sailors asked us about the conditions off the coast. We told them, “Complete crap! Good luck!”


From France we headed north to the Channel Islands. Independent bailiwicks of the UK, the islands are known for tax shelters and their notorious currents. Swirling around Jersey and Guernsey are some of the strongest tidal streams in the UK.

Alderney Race, the narrows between France and the northernmost Channel Island, turns into a seething, boiling cauldron of viscous liquid at the turn of the tide. We arrived an hour later than we’d hoped for and couldn’t punch through the miasma to reach a gentler current. In the end we gave up and sailed back to Alderney at 13 knots. A new record for us. The next morning we flew by the Race, reaching Cherbourg in half the time it would take normally.

It was a bit like sailing upstream on the Columbia River: you can make six knots and go absolutely nowhere. Should you tire of the view of McMenamin’s beer garden, you have to turn around and head west towards Astoria. (I’ll have more on our visit to Guernsey in an upcoming post.)

Ebb and Flow

Tides and currents shape the environment in these parts. You can try and fight them, but you’re better off waiting until the tide turns and the current sets in the direction you want to go. You’ll expend far less energy, and with a little planning you’ll get to your destination more quickly. It’s all in the timing – like so much of life.



  1. Interesting read Mike, do sailors use trigonometry when calculating motion through current dynamics?
    We sometimes experience total whiteouts in blizzards where you can distinguish up from down, totally disorienting. Is it similar at sea in a dense fog?

    1. Thanks Dan. Yes, we sailors use a lot of trig. Or I should say we used to. These days computers do most of the heavy lifting, giving us more time to steer the boat. I don’t find the problem of up/down disorientation a problem. Mostly because we’re piloting something the size of a school bus around and that has its own environment. The bigger problem is fear and stress fouling up decision-making. The best thing is often to skip sailing in fog and head to the pub, or library instead.

Leave a Reply

Your email address will not be published. Required fields are marked *