system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout 4] How is there Irish and Russian accents in the Commonwealth?

So the Commonwealth doesn't really have a huge shipping industry anymore. And although running boats exist (far harbor) I'm doubtful that they can tackle GOING TO IRELAND. 
 
Travel is much harder, so how is there a couple of Russians running a bar, and some irish running around kicking ass and doing hard drugs?
gpt
There is actually transatlantic travel. Colin Moriarty from Fallout 3 is from Ireland and arrived in the US as a child.

Oceanic travel is actually pretty straightforward, if rare, in the post-war world. All you need is a watertight hull, working engine, a nuclear reactor to power the engine, and enough supplies to last the trip.