A spherical pressure hull is one of the most critical components of manned submersibles. Almost one-third of the submersible's weight is occupied by it. This paper describes the process of the structural design of a shallow water steel spherical pressure hull. The classical design rule is used to arrive at a preliminary estimate of spherical pressure hull thickness. Furthermore, a comparison of the design of a spherical shell using different standards is carried out to determine the final thickness of the spherical hull. Additionally, numerical analyses are carried out to verify the analytical calculations. The analytical and numerical results suggest that the shallow water steel spherical hull must have a minimum thickness of 25 mm. Pressure hull design, including the viewports and hatches, follows standard practices and is dependent on materials and manufacturing methods. Numerical analysis is used to verify the hatch and viewport design developed in accordance with ASME PVHO-1. Based on numerical verification, the viewport and its flange stress levels are within acceptable limits. However, the numerical verification of the hatch assembly shows a relative lifting action on the hatch under hydrostatic pressure. This lifting action has to be prevented by a suitable hatch locking mechanism.
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