I’m with you Robert. The design doesn’t make sense to me as a Mechanical Engineer either. But there is a reason. God knows there are a gazillion of those things on the ocean floor, so the design is no accident.
They were probably pointed so as to insure that they were stacked in an upright position using a rack or other means, like soft clay or sand in the bottom of the ship. The sealing methods were probably not that great at the time, so if they were tilted they would leak or become tainted. ...........just a guess.............
Just looked it up on Wiki:
Neck amphorae were commonly used in the early history of ancient Greece, but were gradually replaced by the one-piece type from around the 7th century BC onward. Most were produced with a pointed base to allow upright storage by embedding in soft ground, such as sand.
Amphora - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/AmphoraWikipedia