LOL… a buoy! Ah, yeah, that makes sense having one topside for surface details. I’m sure they got forgotten on occasion… esp if a PBY or Swordfish was sighted and everyone rushed below decks to man their stations. I can imagine a very startled seagull when one of those things suddenly popped to the surface like a rocket.
A swan? Guess that’s as evident as it being a goose 😀 Btw, I just Googled U-Boat mascots and see a litany of entertaining images… no girls though (guess that was just us/US), but I did find a horseshoe (http://www.uboataces.com/ref-insignia.shtml). In all honesty I expected to see more skulls and cross bones. Despite their misguided intentions, the Nazi’s had brilliant design and propaganda, so these mascots/insignia are a bit surprising. I can see Goebbels throwing tantrums about it. Screaming at some unsuspecting underling replying with, “But Herr Goebbels, you insisted your designated images be painted in acrylics. The Fuhrer gave us his personal collection from his time in art school… but the boats are designed to sink and…” !!SLAP!! Another insubordinate underling sent to the eastern front.