It is known that an elastic cylindrical lossless shell immersed in an acoustic fluid can guide acoustic energy longitudinally without attenuation. In fact, for the physical and geometric parameters within suitable ranges, different surface wave modes, with different angular dependence around the cylinder, can be supported by the structure. These modes propagate longitudinally with subsonic phase velocities, and are evanescent in the transverse direction. The concomitant dispersion relationships, which provide the phase velocity versus frequency, are here established by using a thick shell model, in the form of a transverse resonance equation. Numerical results indicate that for frequencies greater thanka≥∼5 the surface wave propagation tends to become isotropic. This effect is manifested by the change of the shape of the dispersion curve, relating longitudinal and circumferential wave numbers which turns into a circle from the ‘‘figure 8’’ characteristic of the low‐frequency regime. The intensity vector field in the fluid and in the shell are studied for different surface wave modes, at different frequencies with the aim of understanding the mechanism of the power flow. For the axisymmetric case it is found that in the lower portion of the frequency region of existence of the mode, the power flowing in the fluid is substantially larger than in the shell, whereas at higher frequency the situation is reversed. For nonaxisymmetric modes the power flow within the shell is higher than in the fluid with the exception of then=1, mode for which in a limited frequency region the power transported within the fluid is slightly higher. Also for the intermediate frequency range, i.e., ∼2