Barney mentions a play from the play-book "the Royal Archduke of Grand Fenwick". This may have been taken from the 1959 film "The Mouse that Roared. There was no Arch Duke in that film. But there was a Grand Duchess of Grand Fenwick. Because the film is set in the fictional country of Grand Fenwick. This was probably an homage to that great little comedy.
On the pictures of the boat in the captain's apartment, there's a little picture of Becky and "boats, boats, boats" in the bottom left corner.