Why is a submarine called a pig boat?

Answer 1

From the shape- and the snout like appearance - the bow, ballast vents and/or torpedo tube openings.- Term more popular in World Wars I and II, now virtually obsolete- it was also mildly derisive- Pigs- the animals are dirty and submarine warfare was considered somewhat underhanded as well as undersea. Term used on both sides in War I. ( it was also applied- to non-submersible Whalebacks- ships with cylindrical like hulls that did, on the surface, somewhat resemble subs. Whalebacks are long gone except for one or two museum pieces. Italian midget submarines in World War II were commonly referred to as Pig Boats- it is said they were transported by truck near the action scene- and were more or less based at some state-owned Pig Farms- the term )Pig-boat for Sub antedates this. they were, somewhat oddly painted in a rust-retardant olive drab like Army tanks.