Fig. 12. (A) Slip, (B,C) propulsive efficiency and (D) jet thrust as functions of swimming speed. Equations of curve fits, when shown, are for solid curves. (A) Slip calculated as u_j/(Ucosß)-1 (data points and solid curve) and u_j/U-1 (broken curve). (B) Jet propulsive efficiency as calculated from Eq. 3. (C) Jet propulsive efficiency as calculated from a three-dimensional approximation of jet kinetic energy (data points and solid curve) with the fit curve from (B) for comparison (broken line). (D) A comparison of average jet thrust determined from jet velocity, the change in momentum in successive jet visualizations, and the unsteady jet analysis of Anderson and DeMont (2000). Error bars represent 95% confidence limits.