Sentence:  Weakened by the strains of sailing in a severe gale and, no doubt, by the accumulated bangings and endless <WSD>slattings</WSD> of the previous year's ocean calms, the top batten had fractured, creating an ineffective and unsightly deep V shape in the top sail panel. 
Meaning of the word marked with <WSD> tags:  The violent shaking or flapping of anything hanging loose in the wind, as of a sail when being hauled down.