@icarushector There is some History/Lore here that I am not familiar with. Who? What?
The U-556 was to rondevu with bismarck since they are low on fuel and out of torps.
In january 1941 U-556 commissioning ceremony approached and they wanted to hire a band for it but couldnt afford one so Commanding Officer of Bismarck lent his ship's band. Because of this, The U-556 pledge is made as thanks and promise that they will protect big brother bismarck from air and sea with a drawing of Percival(knight of the round table) atop U-556 stopping planes and torpedoes coming to bismarck
Fun fact they are neighbours during construction