Regarding what prompted the post, its probably not coincidence that the subject of liquid helium pumps came up in a Worldbuilding Stack Exchange question earlie

Regarding what prompted the post, its probably not coincidence that the subject of liquid helium pumps came up in a Worldbuilding Stack Exchange question earlier today: http://worldbuilding.stackexchange.com/questions/70788/how-could-a-submarine-like-vehicle-steer-and-propel-itself-in-a-superfluid http://worldbuilding.stackexchange.com/questions/70788/how-c... .