He wouldn't have been free to go to Collinsport without being ordered there, so I always pictured something naval mixed in with the Collins literal port, at least a naval ship anchored there where he worked. It seemed odd that Joshua could get him into trouble with the Navy, as if he had authority over them, but that seemed as if it must be interesting historical detail that I'm not familiar with, not a mistake.
Gerard makes some sense of it here. I think there was a transition period when Trask started bullying him, but we saw very little of it on the surface. It also occurred to me reading Gerard's post (this is something I think about) that people may not be "good" or "bad" when unchallenged. We may hover around a neutral midpoint on the good-bad scale. Then when some event comes along that calls for a moral response, we choose and become better or worse people, perhaps temporarily.
This was leading into another point, but I've forgotten it completely. That happens a lot to me. I may be back here if I remember.