Slitherine

Anyone know what the 12 torpedo attack in the units.csv is based on (in real life stat)?
I believe the numbers are used for:
5 turns to reload
Torpedo attack within 2 tiles
12 torpedo attack

That would actually be interesting to know. Never understood the torpedo properly.
The manual says when you torpedo a big ship and when that ship hasn't moved but has attacked, then you deal the highest possible damage. Right?