The issue:
The diving bell hatch in the following area seems to be inaccessible - at least I wasn't able to interact with it from several angles and a good chunk of floor around the diving bell can't be walked on either (nor did -makesafe help).
Area name: Ocean Floor (Siren's Call)
Area ResRef: nw_14
What I expected to happen:
Interact with the hatch and continue my trip.
What actually happened:
Couldn't interact with the hatch and had to lens out