[UKönig]

The duties of the watch were split amongst the crew in a U-boat typically as follows:

The Captain.
Usually referred to by his shortened title "Herr Kaleun" or "Herr KapitänLeutnant"
Or sometimes "the Old Man"
The Captain had to know a little bit about every system on board. He made the life and death decisions and disciplined the crew. He made the attack observations and passed that information off to the First Watch Officer. Also oversaw the distribution of beer or liquor as well as treats such as chocolate to reward for a job well done, or punish the crew for insubordination.

1WO -Erste WachOffizier
Executive Officer and second in command after the Captain. Was also responsible for managing the first watch 0400-0800, and overseeing the calculations into the TDC during surface or submerged attacks.

2WO - Zweiter WachOffizier
Second Watch officer, managing the bridge second watch 0800-1200 as well as all flak and /or deck guns. Was also typically responsible for the radio crew and decoding Enigma transcripts with a cypher key known by him. The Captain also had his own cypher key for when the message was in triple code and thus "for captain's eyes only".

3 WO - Dritte WachOffizier
Third watch officer or Obersteuermann 'chief navigator' in overall charge of the helmsmen and navigational duties. Also saw to the care and maintenance of the sextant and other sea charts. Was also chief quartermaster responsible (along with the cook) for the storage and distribution of supplies, especially food stock, in such a way that, they had to be stored securely so as not to come loose during battle, they had to be distributed so that underwater trim was not disturbed, and in such a way that access to handles, hatches and valves was uninterrupted, and that perishables would be used up before the canned goods that lasted.

Leitender Ingenieur - Chief Engineer and Fourth watch officer. The go-to guy for all matters technical aboard your boat. Has (often) final say regarding the the operational condition of the diesel engines, electric engines, batteries, pumps and compressors, fuel state etc.. as well as setting the scuttling charges should the order to 'self-destruct' need to be carried out. As such, a lot of LIs went down with their boats. He was also responsible for the primary acquisition of supplies before every mission.

The rest of the men were often little more than flesh and blood links in a badly designed chain. Torpedo boys who serviced and loaded the primary weapons of the boat. Often little more than muscle, because torpedoes can't load themselves. Radio crew or Funkmaats. Two or 3 crew trained to handle the sensor systems of the boat. From the hydrophones and sonar to the wireless telegraph and radar and radar warning receiver, their jobs also included the ability to repair these electrical systems. Diesel stokers and E-machine stokers, responsible for the care, maintenance and operation of their respective areas. And then the watchmen or look outs along with the planesmen who handled the hydro planes and diving panel for the overall control of the boat. And finally the Cook. Often regarded as the second most important man on board after the Captain. You'll want to get on good terms with him right away. When patrols are long and morale is low, it's good hot food that can turn that frown upside down.

Sometimes 'guest crew' would be invited on board. These could be war correspondents, writing articles for propaganda purposes, or 'would be Kaleuns' who need to attend a war patrol before their final promotion and acceptance of command. Same goes for Engineering crew, who may need a bit more practical experience in real wartime conditions, before assuming command as a department head on a boat of their own.