The vocals seem like they would sound better isolated rather than in harmony.
The reason I say that is because the vocalists both have very trembly voices. They fight each other and drag focus away from the lyrics and the song. The tremolo-reminiscent voices also influence harmonies to sound off.
The choral "oohs" and "ahhs" work incredibly well, though.
I think of Irish Pirates when I hear this. And that's a good thing.
Isaac Brock from Modest Mouse (early Modest Mouse, not that lame poppy shit they put out now) reminds me of a pirate as well.
Good job. I really enjoy the track.
Hope my criticism finds you well and I hope you keep uploading music.