Hi guys,
I like to have my starting crew composition as close as possibile to reality as we can read and learn here
http://uboat.net/men/crew/.
Hence in my U-48 VIIB career I will always have:
4 officers:
LI: usually an Obrltn.s.z. with Repair and Machinist qualifications
IWO: usually an Obrltn.s.z. or a Ltnt.s.z. with Watch, Torpedo and Helm qualifications.
2WO: usually a Ltnt.s.z. or a Fanrich s.z. with Watch, Flak and deck gun qualifications.
NAV: usually a Fanrich s.z. ,even if it would be great that SH3 Commander would allow to "demote" this officer to a Chief Warrant PO as the Obersteuermann was usually a Chief PO, with Watch, usually he was the 3rd watch leader, and Helm qualifications.
Then, starting from the 3rd patrol, I use to take on board a junior officer on his first post training deployment. This one can be a IWO, a 2WO or a LI (I change to my desire his qualifications using SH3 Commander) with one or two qualifications according to his training duty.
I then dismiss this one after a couple of patrols or, if my feel "sparks" for him, I might decide to keep him on board for active duty.
14-16 POs.
Chief POs.
1 CPO acting as leader of the torpedo rooms with Torpedo and Repair qualifications (yes, I know that only one qualification works for POs but I am a hardcore realism seeker).

2 CPOs acting as leaders of the engines compartiment (Diesel Obermaschinist and Electro Obermaschinist) with Machine and Repair qualifications.
1 CPO acting as crew discipline leader and lookout leader (when I run surfaced w/out a watch officer on the bridge) with Watch and Helm qualifications.
1 CPO acting as Oberfunkmeister/Sanitätsmaat with Radio/Sonar and Medic qualifications (no medic officer on VII class boats, only on larger IX class). This comes straight from Das Boot movie
Other POs.
1 PO acting as Steuermann with Helm qualification.
1 PO acting as Funkmaat with Radio/Sonar qualification.
2 POs acting as Obermaschinist with Machine qualification.
3 POs acting as Torpedo Mecanikaermaat with Torpedo qualification.
1 PO acting as Repair team leader with Repair qualification.
1 PO acting as Flak gunner team leader.
1 PO acting as Deck gun team leader
Other ratings.
I usually start the Campaign with 4 Matr.haupt.gfrt. with the following qualifications:
1 Funkgast with Radio/Sonar qualification.
1 Artilleriemechaniker with deck gun qualification.
1 Torpedo Technisches with Torpedo qualification
1 Machine Technisches with Machine qualification.
Of course these won't works in the sim engine but are a nice eye-candy.
During the course of the career, these ones could be promoted to PO ranks.
As the career goes on I promote the other ratings up to Matr.Hpt.Gfrt. giving qualifications at my own taste.
For example I like to have another Funkgast, so that I always have a PO and a qualifitied rating in my Sonar/Radio rooms, some other Flak gunners when other AAMGs are implemented on the sub, another deck gunner in order to have a dedicated deck gun team, other torpedo, machine, repair and helm qualifications.
Greetings and good hunting!
Mau Fox