The groyne protects Cottesloe beach from larger waves and makes it a perfect bathing spot. The distance between the groyne and the ocean pylon (see previous post) is approximately 150 metres, ideal for 'lengths' and you don't have to mess around with all those tumble turns like in the pool; or the chlorine for that matter! Ten lengths is equivalent to 1.5km the swim leg of a Olympic distance triathlon, perfect to wake you up in the morning.
Distance from the pylon to the groyne (click to enlarge)
Here is the geomodel of the Groyne:
And here is the Ocean Pylon (further details are in the previous post). You need to zoom in to see it properly!