In the previous papers 1), 2), authors presented experimental and theoretical data on propeller open characteristics, propulsive performance characteristics, cavitation characteristics and propeller-induced fluctuating pressures of MAU type conventional propeller (MPNO. 80-3), conventional 90° Highly Skewed Propeller (HSP) (MPNO. 80-4) and theoretically designed 72° HSP (MPNO. 80-5). In this report, static stress on the blade of MPNO. 80-5 is first presented. The stress was measured under the condition that concentrated force was loaded at a point on the blade. Principal stress measured is compared with that calculated by using the finite element method ; SPROSAS (Highly Skewed Propeller Stress Analysis System)¹²⁾ which was developed for this research project. Calculated results agree well with experimental values. The outline of SPROSAS is described. Then, fluctuating stresses on the blades of MPNO. 80-3 and MPNO. 80-5 working in the wake of 7m container ship model are also presented. The stresses were measured at ahead, crash astern and astern conditions in towing tank. Mean stresses for one rotation measured at ahead and astern conditions are compared with those estimated by using SPROSAS. Pressure distributions on the propeller blades are calculated by means of non-linear lifting surface methed.¹³⁾ Calculated mean stresses agree with experimental values for MPNO. 80-3. For MPNO. 80-5, calculated mean stress distributions on the propeller blade qualitatively correspond to those of experiment even though calculated mean stresses are smaller than experimental values.