Complex sentence: A related feature of the G3 and N3 designs was their tower bridge structure behind the first two gun turrets, which reduced draughts, provided a better and more stable foundation for fire control gear, and could be made secure against gas attacks.
Split into simpler sentences: A related feature of the G3 and N3 designs was their tower bridge structure behind the first two gun turrets. This reduced draughts, provided a better and more stable foundation for fire control gear and could be made secure against gas attacks.