Results of a numerical and experimental study into buckling performance of multi-segment pressure hull subjected to uniform hydrostatic pressure are discussed. Constituents of multi-segment configurations are bowed-out cylindrical shells with, and without flanges. Details about five collapse tests of laboratory scale mild steel, CNC machined models are given. Segments were about 200mm diameter, 100mm long and had uniform wall thickness of 3mm. Experimental collapse pressures were in the range from 12 to 20MPa. Numerical collapse pressures agreed well with those obtained during experiments.