 All three vessels sported four funnels, with the fourth being a dummy which was used for ventilation purposes.Smoke from the galleys and Smoking Room fireplaces and fumes from the engine rooms was exhausted through a chimney up the forward portion of this funnel.On the one hand it was a decoration to establish a symmetry in the ships' profile, on the other hand, acting as a huge ventilation shaft, it prevented the large amount of ventilation cowls on deck as on Cunard's "Lusitania" and "Mauretania".