A friend of mine was a merchant marine. He said that before the Exxon Valdez incident, it wasn't unusual for one of the big cargo ships to be at sea undermanned because most everyone on board would be under the influence of something. He said that as an 18 year old, he woke up one day to find the ship unhelmed in a storm, the captain passed out in a drunken stupor, and he was left alone to pilot the ship (with the vague instructions from the owner to "head towards South America til I find us a job there"). He said after the Valdez incident, everyone started implementing drug and alcohol testing and it changed everything.
He knew Joseph Hazelwood and said the blame was unfairly placed on him (though I don't really understand the story he tells). My friend wasn't on the Valdez, but he was on the cargo ship that crashed into the boardwalk in New Orleans in the mid-90s. He said back in his early days, they relied on some ancient sailing guide for maps and navigation, there were no electronics guiding the ships he was on, it was almost all manual.