Fig. 11. Thrust required to change the Baculites compressus model orientation (θa). A. Thrust Scenario 1: A continuous thrust supplied to the venter with a similar thrust ratio to Nautilus (Table 1). The average change from a vertical resting orientation (Δ θpeak) is 22.7°. B. Thrust Scenario 2: Periodic pulses from a pump with a simulated mantle cavity of 20% soft body volume of B. compressus (Table 1). The average change from a vertical resting orientation ( Δ θpeak) is 25.6°. C. Thrust Scenario 3: Periodic pulses from a pump with a thrust ratio between Sepia officinalis and Loligo vulgaris (Table 1). The average change from a vertical resting orientation (Δ θpeak) is 72.2°. Average peak thrust (Fpeak) error bars represent one standard deviation calibrated from 30 second intervals of pumping.