Hi I tried to do this myself to and it seems to work better. The Mass = line in all the Sub .Sim files is 0 so I tried putting Mass = 1798 and also the line gc_height = 2.4 for the Balao and it seems to work better. In the Sim Cfg I put Waves Amplitude=0.85 and Waves Attenutation= 0.05 i'm still experimenting with these values though. Also the ranges or milesSurfaced setting under Diesel Propulsion in the Sim files are a little inaccurate I think so I put the numbers from
www.fleetsubmarine.com in to. Hope this helps.