…but that doesn’t mean we shouldn’t check our assumptions like it. Spain recently had an issue with a submarine that would have acted as a very expensive anchor.
Designing a submarine is an intricate balance of everything, power systems, oxygen systems, weight distribution, and buoyancy. All these systems need careful planning, and have to be accounted for together. Starting with a wrong specification at the early stages is a catastrophe as all other design systems will cascade and have issues to.
It’s much easier to be super thorough at the beginning than to figure out fixes later. Always check assumptions as early as possible in a large project. Double check, then also have someone else check. There is a lot at stake.