Originally Posted by Rhodes

Always thought that the "christmas tree" of the u-boat was the box with red lights only next to the ladder to the coning tower;the front of the device is facing the engine telegraphs, and in SH3, the chief engineer.

Jimbuna, when I first saw that pic, also thought that their were celebrating Christmas, but their are in fact celebrating the oak leaves of their commander, but You know that.

Originally Posted by Sailor Steve

I don't know if the u-boatmen used the same terms, but to an American submariner "Christmas tree" was always the 'open/closed' indicator panel, simply because the 'open' lights are red and the 'closed' lights are green.

And obviously Ducimus' links answered the "do u-boats have them" question in the affirmative.