after the united states occupation of veracruz on 21 april 1914 (which found six american-hawaiian ships in mexican ports), the huerta-led mexican government closed the tehuantepec national railway to american shipping. this loss of access, coupled with the fact that the panama canal was not yet open, caused american-hawaii to return in late april to its historic route of sailing around south america via the straits of magellan. with the opening of the panama canal on 15 august, american-hawaiian ships switched to taking that route.