Well... you could go to your C:\Users\<user>\Documents\SH4\data\cfg\savegames\ and edit the ActivePlayerUnits.upc file with notepad where it says...
[UserPlayerUnit 1]
ID=Sargo
NameDisplayable=Sargo
UnitName=USS Spearfish (SS-190)
UpgradeClass=1
Type=Sargo
UnitInterval=1939-01-16 00:00:00, 1946-12-11 00:00:00
ExternalClassName=SSSargo
Nationality=American
Evolution=Normal
Damage=0.000000
TextureName=data/Submarine/NSS_Sargo/NSS_Sargo_T01.tga
LightmapTextureName=data/Submarine/NSS_Sargo/NSS_Sargo_O01.tga
NormalmapTextureName=data/Submarine/NSS_Sargo/NSS_Sargo_N01.tga
MenuSilhouetteTextureName=Salmon_Class_01.tga
MaxOfficers=24 <-- change this
MaxPettyOfficers=30 <-- change this
StartUserPlayerUnitMissionDateTime=1941-12-07 13:00:00
CurrentUserPlayerUnitMissionDateTime=1941-12-07 13:00:00
SilentState=false
For best results and no CTD's, do it in port before you go to configure the crew.
At the start of a carreer is a good time too.
You can also edit the player renown the same way in a file called CareerTrack.upc 