Sentence:  Rhythmic beaches consist of a rhythmic longshore bar that narrows and deepens when the <WSD>rip</WSD> crosses the breaker, and in between broadens, shoals and approaches the shore. It does not, however, reach the shore, with a continuous <WSD>rip</WSD> feeder channel feeding the <WSD>rips</WSD> to either side of the bar. 
Meaning of the word marked with <WSD> tags:  A strong outflow of surface water, away from the shore, that returns water from incoming waves.