Structural Optimization for a Spherical Pressure Hull of a Deep Manned Submersible Based on an Appropriate Design Standard

As the most critical component of a deep manned submersible, the manned pressure hull provides a safe living space for pilots and scientists under the deep sea pressure, and its weight occupies almost 1/3 total weight of the manned submersible. So the pressure hull should be designed to have enough strength and should be as light as possible. However, a comparison of the current available design rules from various classification societies indicated significantly different results among these design rules and many existing spherical pressure hulls are found to be not in compliance with most of the current design rules. This indicates that current design rules need to be updated and unified, similarly to the Common Structural Rules for tankers and bulk carriers. To update the design rules, a systematic study is carried out. Then, a new design standard based on this study is proposed to the China Classification Society (CCS) for consideration of updating their rules. The main purpose of this paper is to briefly summarize the study on this new design standard and to present the structural optimization of the manned spherical pressure hull of a new 4500-m rating manned submersible based on this new standard.