For our first two weeks back in Ireland, we were living in Sandymount, on the shore of Dublin Bay. At low tide, a vast area of flat sand is exposed, extending far out into the bay. It’s a great place for the dogs to run around. This is the beach where Stephen Dedalus “walked into eternity”, and it often looks as if it is possible to do just that. I became curious to know just how far from the shore you really can walk, when the tide is at its lowest. One Sunday morning I got up at 6 a.m. and set off with the dogs to find out.
Such an adventure is not without its perils, as this sign reminds us:
This warning is no joke, and I didn’t take it lightly. I am no stranger to the risks of incoming tide, having got into serious trouble in the past and been lucky to survive. On this occasion I made sure that when the tide turned, we would be on our way back, even if we had not reached the edge of the sand.
The greatest tidal range (lowest and highest tides) occur in March/April and September/October, around the time of the full and new moon (actually there is a lag of a day or two). In March 2011, there was a spectacularly low tide, about 4 cm over datum, and my dad and I took the opportunity to explore the sea bed at Shankill beach, where we hoped to find the remnants of a drowned mediaeval village.
On this Sunday in May, the tidal range was not so great, the low being around 70 cm OD, so it was not a day for setting records. Nonetheless, the sea had retreated very far, almost out of sight. The two ships visible on the horizon look odd, almost as if they are sailing across the sand.
One thing I learned in recent weeks is that the sand is not at its driest at the time when the tide is lowest. The recently exposed sand flats hold a lot of standing water in ripples and pools, and it drains off into channels which resemble streams or rivers crossing the beach. The largest of the channels is called “Cockle Lake” on the charts, or as Joyce would have it “Cock Lake”. The sand continues to dry out for several more hours until eventually inundated by the returning tide.
Between the channels there are larger areas of relatively dry sand. It is here that one is liable to get stranded by the incoming tide. Even at its fastest (about 3 hours after low tide) the average speed over ground probably doesn’t exceed 1 km/h, so it will not outpace you. But it will outflank you. The incoming tide backfills the channels and divides the strand into temporary “islands”, so that you can be standing on a dry (but shrinking) sandbank and be surrounded by deep water. This happened to a family some years ago, and by the time they were rescued by the lifeboat, the father and mother were chest-deep in cold water and holding their young children. Thankfully nobody was harmed, although it must have been a very frightening situation.
In this photo we are looking back at Strand Road in Sandymount from a distance of around 500 metres from shore.
This next photo is taken at a distance of 1 km from shore. The UCD water tower and the RTE TV mast are visible near the right of the picture. The Aviva stadium is also visible but may be hard to make out.
Looking north from the same point, we are parallel with Poolbeg power station and the Shelly Banks. The little muddy spirals on the beach are the casts of lugworms, often dug up by fishermen and used as bait.
In the end, we reached a point about 1.4 km from the shore before turning around and heading for dry land. Had I been more reckless, we could certainly have gone much further; as you can see in the photo below, the edge of the sand still seems very distant.
But time and tide were against us, and I was taking no chances. Here is an image of our track on Google Earth:
On our way back to shore, we came across these seaweed-covered rocks; a rare splash of colour in a world of greys and browns. Strange to think that 6 hours later, they would be under 5 metres of water.
We also found this mysterious rope. Each end disappeared into the sand and was firmly stuck.