Sentence:  The "Independencia" is a two-turreted, <WSD>breastwork</WSD> ship of 9,000 tons displacement. ... The central <WSD>breastwork</WSD> is 130 feet in length at the top of the belt, and extends to the upper deck, 11 feet above the water-line. This <WSD>breastwork</WSD> incloses the boiler and engine hatches, the scuttles to magazines and shell-rooms, the principal openings for ventilation, and the two turrets. 
Meaning of the word marked with <WSD> tags:  A railing on the quarter-deck and forecastle.