View into the electric motor room from what is now the tourist exit. Visible in the background is the electrically-powered air compressor. The large red and green switch on the bulkhead above it to the right sources the compressor motor’s power from either battery via either main switchboard in the room. In nautical terminology the color red is frequently used to mean port and green is frequently used to mean starboard. Also note that in these photos green generally shows up as black due to the lighting conditions. To remember which is which, think port wine is red. In this example, the green side of the switch sources from the starboard switchboard. The small white tank to the right of that switch is the distillate gravity tank. Further to the right is the round pressure hatch leading to the stern torpedo room. A diesel-powered air compressor would sit right where visitors exit the boat. This compressor is visible in the U-505 exhibit outside the boat. (Caption courtesy of Matt Hamacher)