Sea swimming in June: tides, a current I misjudged and the thirty-metre rule
June is when the lake gets weedy and warm and I move my swimming to the sea, and every year I have to relearn that the sea is a different animal. The water on Sunday was 16 °C, a temperature I would not even call cold in winter terms, and the cold was indeed the least of it.
I got in at a shingle beach I know well, an hour before low water, and swam parallel to the shore as I always do, about thirty metres out, where the waves had stopped breaking and the bottom was still within reach of a downward kick. After what I thought was fifteen minutes of easy swimming out and back, I put my feet down and looked for my bag. It was 200 metres away, back along the beach. I had been swimming against a longshore drift one way and with it the other, and the two had not cancelled. The “back” leg had carried me well past my start without my noticing, because I was watching the water in front of me and not the land beside me.
Nothing came of it except a long walk over shingle in bare feet. But two hundred metres in fifteen minutes, in a current I had not felt, is the kind of thing that turns into a problem if the wind is offshore or the drift runs towards rocks or a groyne. The lake has taught me cold. It had not taught me that water moves.
The checks I now do every time, before my feet are wet. The tide table, not for the swim itself but to know which way the water will be moving and whether I am swimming on a falling tide, which in that bay sets strongly east. The wind direction, especially anything blowing off the land, which flattens the water and makes it look safe while pushing a tired swimmer out. A landmark on the shore lined up with something behind it, checked every few minutes, so that drift shows up as the two things moving apart. And the thirty-metre rule, which is mine: I stay within thirty metres of standing depth at all times, because a current I can stand up in is an inconvenience and one I cannot is an emergency.
The water was lovely, clear enough to see my hands and the ribbed sand below, and I swam again on Wednesday with a landmark lined up and came back to within ten metres of my bag. Sixteen degrees. The easy part.