- • + Buoyancy 



Net Downward Force 

 (a) Free descent. 



Descent Velocity 



drag force 



Buoyancy 



sea bottom 



Net Downward Force 

 (b) Free ascent. 



T 



Descent Velocity 



— [ + Buoyancy 



Net Downward Force 



(c) Forced descent and restrained ascent. 



Descent Velocity 



Figure 5. Hydrodynamic profiles of buoyancy, force, and velocity. 



29 



