This looks like a culvert pipe or something, discharging out to sea. The concrete platform is the ideal place for the surfers to work from on this beach. I have edited the ghostly shadows out and a terrible error of catching my camera shadow. I had a little Photoshop work with the content aware using the patch tool and clone stamp.The symmetry of the marker and its reflection of the pole in the water, against the lovely blue sky, and the fluffy clouds bringing the eye in towards the marker. I played with a little rule of thirds for the sky, sea with reflected sky and the sand keeping the marker as the center point, using the platform as leading lines. Clumps of seaweed and footprints in the sand add a little to the scene, as do the ships on the horizon.
Taken with Big Stopper plus 0.6 ND soft Grad 9 second exposure at f16 and ISO100. For seascapes it is usually recommend hard-edged graduated filters are used. I think this one turned out okay, as the graduation was still in the sky leaving the sea and sky horizon still well-defined.