Using Rubidium together with Panthalassa makes the submarines default perspective basically unusable, as all terrain will stop rendering depending on the viewing angle, especially when looking from above. The first person view from inside the cockpit works fine, but then the vehicle positioning becomes impossible to assess without dismounting inbetween.

Tested with:
Forge 43.1.43
Panthalassa 1.3.0
Patchouli 77
geckolib 3.1.28
Rubidium 0.6.2