I do think he has a mile-wide romantic streak though - not in the horrible modern sense of the word, but in aspiring to, and admiring, grand things. Joining the Navy, and his excitement at getting to go to war, seem to be a part of that

And there was a lot of that going about during that time in poetry, literature, art, etc., plus the fervent nationalism and fear that the French were about to land on English soil ANY MINUTE NOW so yeah, a young man could easily buy into it all.