Hull damage and consequences

[Triad773]

Hey guys- been going thru sub school and the like. Been extending my training missions by clicking "Return to game" and navigated from the NAV site to Pearl for fun.<took a very long time, but for someone with flu, what the heck!>

Hey one thing I think I learned: I wound up by an island named 'Kolonial' with docks- don't know whose or something like that: getting my way around the islands I ran into trouble in the way of a sandbar or something: got the repair crews working on all issues and wound up with 82% battery capacity, and more importantly, "Hull damage: -84%". I went to 80 feet and imploded some time later (sorry, no clip available ).

So- my question is, what exactly does "Hull damage: -84%" in the Damage Control panel mean in this case? Trying to make ALL my noobish errors in some meaningless mission so I got it right when it counts.

I had done a search of the PDF manual as well as this forum for the term "hull" but came up null

Thanks in advance for any and all advice.

Triad