[QuarterReptile]

What you're looking at there would suffice as source material whether your keel depth is 30ft or 300, and then many layers of planning happen atop it.

> like is there a big geologic underwater arch somewhere that subs pass under for shits and giggles.

I can't promise there's not, but most naval services have proud traditions of firing captains who are involved in collisions, allisions, and groundings.