"There are only two kinds of ships," the volunteer told me on the gently rolling deck, motioning toward the container ship sailing past Alcatraz. "Submarines and targets, and that's a nice big target."
USS Pampanito is one of the nine surviving Second World War Balao-class submarines, now spending its time at San Francisco's Maritime National Historic Park. During the height of the Pacific war, dozens of submarines just like her prowled the deeps - many didn't come back.
Pictured here is Pampanito's main gun, a 5"/25 caliber anti-aircraft weapon. Though I don't know how well something like that would do to sink a modern container ship. Probably not very; there was, after all, a very good reason that subs were given torpedoes.
I, the copyright holder of this work, hereby release it under the Creative Commons Attribution-Non Commercial-Share Alike 3.0 Unported license.
This means that you are free to Share (to copy, distribute and transmit the work) and to Remix (to adapt the work) under the following conditions: Attribution (you must attribute the work in the manner specified by the author or licensor, but not in any way that suggests that they endorse you or your use of the work), Noncommercial (you may not use this work for commercial purposes), and Share Alike (if you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one).