It's a shitty translation.
There should be a lot more sexual innuendo in here and nautical lingo. ""All hands on deck" "hoist the mainsail" "Thar she blows!" get it? When the Captain shows up it gets down to pirate business. "Take no prisoners" "Fire in the hole"
Lesson #1: "No prey, No pay"; which means nobody works for wages, it's piracy so everyone share's "the booty". Thus, the gangbang. The captain doesn't say "I'm putting you down now" he saying "I can't keep you to myself. I got to feed the sharks" (the other pirates)
The english translation does something stupid. Kid's (that's his nick name) bandanna falls off as the captain fucks him. He's surrendering. "Waving the white flag". It's not the captain saying "I'm going to fuck you dead" it's the boy saying, "Blow me down." an execution order. lit. "Fuck me." But literal translations are retarded. The purpose of a bandana is to keep sweat out of your eyes and hair out of the rigging. Falling away symbolizes that he's "in with them" now. They jizz over his face.
Then the "important part" where he drinks "the bilge water" (that's where they are) that completes the hazing ritual. Drinking bilge water is like the lowest means of survival. Life out at sea could end in doldrums, stranded with no wind. "Cabin fever". And he offers it to him, saying, this is the "true" taste of a pirate.
He was drinking rum before, now he's drinking cum.
That's called parallel structure.
The English translation fumbles this. In the beginning, they don't yell "Kid, hold on" and rescue him. They tell him, "Kid, hold it there" he's acting as bait and takes one for the team so they can deal with the tentacles. They finish by drinking rum. The second part is below deck, where he takes one for the team, again, as they deal with their own tentacles. And he ends by drinking cum.