 A lighter alternative to the turret , particularly popular with the French navy , was the barbette . These were fixed armored towers which held a gun on a <unk> . The crew was sheltered from direct fire , but vulnerable to <unk> fire , for instance from shore emplacements . The barbette was lighter than the turret , needing less machinery and no roof armor — though nevertheless some barbettes were stripped of their armor plate to reduce the top @-@ weight of their ships . The barbette became widely adopted in the 1880s , and with the addition of an armored ' gun @-@ house ' , transformed into the turrets of the pre @-@ <unk> battleships . 
