Fun In The Swellies: Fighting The Tide In The Menai Strait

Fun In The Swellies: Fighting The Tide In The Menai Strait

Canoes on the Menai Strait
A grand winter’s day out on the Menai Strait. Photo: Paul Kirtley

The Menai Strait separates the island of Anglesey, or Ynys Môn, from mainland Wales. It is a tidal stretch of water that has some interesting characteristics. Flows in this thin, 25km-long channel are driven by the dynamics of how the strait starts emptying or filling from one end before or after the other end. In fact, the differential tides mean the tidal flow in the strait reverses at certain points in time. In between reversals, it can be pretty vicious.

These tidal dynamics alone would make the Menai Strait interesting. There is, however, more.

The strait is bridged in two places, one by Telford’s suspension bridge and the other by the Britannia bridge, originally a work of Stephenson. These bridges cross at relatively narrow points of the waterway. In between the two bridges are various features which make a boater’s life even more interesting. Collectively, these are known as the Swellies or, in Welsh, Pwll Ceris.

In particular, there is a ridge of rock – like the back of a dinosaur showing at low tide – called the cribbin. This is located near the island of Ynys Gored Goch.

Of the Swellies, the local lifeboat station at Beaumaris states “Care is needed if the Swellies are to be piloted successfully and the first passage for any skipper would benefit from the company of a regular. Tidal streams at Menai Bridge are sufficiently strong to drag a boat without a powerful engine into the Swellies so once you are committed there is often no turning back.”

So, there are powerful flows to be expected here. When the water is slack it seems very benign. Indeed our day trip by open canoe started this way, with us paddling along the strait towards the conclusion of the period when the tide was going out.

We started our return leg after lunch with the water level near its low point (where we were on the straight anyway). As we reached the Britannia bridge, the water was coming in from the end of the straight behind us. Then the flows kicked in, tidal rapids appeared over parts of the cribbin and the Swellies became much more interesting, with a constantly changing set of waves and unpredictable boils, resulting from the turbulent flow.

In the video below, there is a log of our day on the water…

Click on the four arrows bottom right for full screen view. This video is available in full HD. Click on “HD” to choose the quality level you want to stream.

We certainly had some fun – and a workout! – in this powerful water 🙂

Related Material On Paul Kirtley’s Blog

Weirs, Waves & World Heritage: Adventure On The River Dee

A Trail Of Destruction: Canoeing The River Greta After The Floods…

Waiting For Gooders: A Minor Inconvenience In The Wilderness

11 thoughts on “Fun In The Swellies: Fighting The Tide In The Menai Strait

  1. That was very exciting Paul! Thank you. Seen from a whole new level. The canoe, not just a conveyance, but a super-charged implement to pump your blood with!

    All the best,


  2. Great video Paul, highlights how quickly the water can change!

    Do you ever have people on kayaks join your Canoe trips?

  3. Wonderful cinematography Paul! The “Swellies”, looks to be an interesting place and you folks described it well-its’ almost possible to feel the surging water. There is considerable to learn here that
    affects safe small-craft navigation throughout our marine environment? I am curious about the behavior of this particular area during the maximum high and low tidal cycles.

  4. Thanks Paul – great production , I really enjoyed it.

    Warm regards,


  5. Hi Paul, thanks for another interesting video. This really reinforced a that my Dad used to use: “water can be a good servant but would be a dangerous master !” I can see that if mis-judged the Swellies could quickly put you in a whole heap of trouble. that being said this looks fantastic fun!!
    All the best, Dave.

  6. Nice Video, it gives a good impression of what the Straits are like in Canoe. its one of my favourite venues.
    Next Time try it from the start of the Ebb tide and go and play on the Whirlpools on the Platters eddy (mainland side 400m west\downstreem of the suspension bridge). On a big Spring tide you can end up with one end of your boat in the eye and the other end about 40 degrees skyward, VERY EXITING!!!!! The good thing is if you swim. you stay on the surface going round and round until they fizzle out after about a minute or so. the bad thing is you may have to get off to change your underwear.

  7. How well that gentleman to change impressions can work oar.
    Warm regards,

  8. Nice footage of what looked like a great day. Loved the turbo paddling against the flow too! Hope you all had a fun session.

  9. Entertaining film. It brought back memories of a weekend on the swellies. Water levels were “interesting” especially when a boat went through the bridge area, it seemed to cause a definite level in the stream. good surfing was also had and a workout!

  10. Last night (10thJan) I watched the documentary about the investigation into Neolithic Orkney on BBC2 – http://www.bbc.co.uk/programmes/b088pnv1 This included crossing the Pentland Firth to the Mainland in a wicker framed hide boat in an attempt to reconstruct the journeys made by early Orcadians. The introduction goes, “Orkney – seven miles off the coast of Scotland, and cut off by the tumultuous Pentland Firth, the fastest-flowing tidal race in Europe is often viewed as being remote.” One of the key features of the Pentland Firth trip was ‘The Swelkies’ which immediately reminded me of the Swellies in your trip. I’m guessing that the Welsh pronunciation of Swellies would originally have been similar to the double “ll” in places like Llanfair P.G. and that the two words, one in Welsh and one in Gaelic have the same meaning, though I didn’t pick up on what that was . The advice about crossing here from the local lifeboat men was “Don’t” but they gave advice anyway and the boat made it across. Just wondered if there are any comparisons to be made with your Menai Straits trip. Great video and I’m glad James stayed in his canoe and that the dog enjoyed the trip.

    1. P.S. Apparently, according to one TV review, ‘swelkie’ is Old Norse for ‘swallower’ so I guess if you see that on a map or chart you should take notice. (Modern Norwegian for swallow is ‘svelg’ which seems similar)

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