Ok well here's what I've found out after a few rather infuriating efforts. Apparently my computer has issues with the external view, no matter how low I set the graphics settings....
Anyway...The Mogami Heavy Cruiser from the training mission is listed as having a draft of 4.4 meters. This converts to approximately 14.44 feet. I fired a number of torpedos at the target to determine the depth required for the torp to pass under keel. I did jump from 25 feet to 28 feet, decided to for go the foot by foot thing. My torp set for contact+influence passed under the keel without exploding. Sadly my computer crashed shortly after I watched this occur. However after rebooting and reloading I fired another torpedo set to run at 28 feet and to explode by contact alone. This torpedo passed 1/3 of the way under the keel and then exploded. I had read something about this before. Apparently the switch is backwards or setting for contact gives you only influence...(Didn't have the patience for another reboot and reload to fire one set on contact that actually hit the side.) Oh yeah and duds were off.
So in conclusion....1. The draft depths in the manual/chart are off. The dial has to be set in feet because 28 meters would have been way to deep. 2. Torpedos set to explode by contact+influence don't, they will explode by influence when set to contact though....
This info is pertinent to 1.2 without any mods affecting ship dimensions or torp stats. Oh and if anyone has any ideas why my computer likes to crash while I'm in the external camera...feel free to chime in...Thanks