A method is demonstrated whereby the velocity of flow during a coastdown transient in a loop may be analytically determined without the use of pump characteristic curves. The method is approximate, and it appears that the error involved is of the order of magnitude that may be expected in hydraulic calculations. A fair agreement is noted when the results of the analytical method are compared with those obtained by the use of the characteristic curves of both a single-suction and a double-suction centrifugal pump. A further comparison of the analytical results with collected experimental data for flow coastdown also shows a fairly good agreement.