A question about WW1 U boats

[breadcatcher101]

I have seen pics of some and they have masts on them. What was the purpose for these? Wireless maybe? They would have to fold down I would think as they would protrude above the scope.

[TLAM Strike]

Yes:

http://img517.imageshack.us/img517/2849/h45618.jpg


Interestingly this antenna design is still in use today! Check out these photos of a captured North Korean submarine:
http://img88.imageshack.us/img88/4654/1270263359convjpg.jpg
http://img692.imageshack.us/img692/4243/1270263359conv.jpg
Notice anything similar?