Hydrodynamic exciting forces on a submerged oblate spheroid in regular waves

► The hydrodynamic diffraction problem by a submerged oblate spheroid is considered. ► The analytic procedure employs the method of multipole expansions. ► The various velocity potentials are transformed into oblate spheroidal coordinates. ► The governing addition theorems are developed and employed. ► The effect of body's volume and immersion depth is highlighted and discussed.