The mission of ABS is to serve the public interest as well as the needs of our clients by promoting the security of life, property and the natural environment primarily through the development and verification of standards for the design, construction and operational maintenance of marine-related facilities. ABS LINKS Main Web Site ABS Document Index ABS Rules for Building and Classing Underwater Vehicles, Systems, and Hyperbaric Facilities. The starting point for design and fabrication of personal submarines.   This document often references other ABS documents rather than duplicating similar rules for various components of a vessel.   For example, this document will tell you to reference ABS Steel Vessel Rules for specific design of the pressure hull (see below).   Unfortunately, ABS tends to change the location of their latest updated documents so a direct link is usually not helpful.   Follow the link above to the ABS Document Index and search for "underwater". Part 4 - Chapter 4;   ABS Rules for Building and Classing Steel Vessels These are the guidelines used specifically for the design of an underwater pressure hull.   Unfortunately, ABS tends to change the location of their latest updated documents so a direct link is usually not helpful.   Follow the link above to the ABS Document Index and search for "Steel Vessel".