10 Stand-Alone Star Trek Episodes More Important Than You Realise
4. Unexpected
Unexpected was originally intended to be a light entry in Enterprise's first season, giving Conner Trinneer a chance to stretch his acting chops, and introduce some new aliens into the mix. While both were achieved, the episode itself could, and arguably should have, simply melted into the background of the season.
And then Klingons appeared.
In the episode, Enterprise must engage with a Klingon Battlecruiser. The CGI model for the K'T'inga Class, a battlecruiser that was introduced in The Motion Picture, was chosen for use by the producers.
An entirely new design of vessel - the D-4 Class - was created by John Eaves. He based it on the D-7 Original Series cruiser, with fewer windows than modern audiences were accustomed to seeing. Rob Bonchune of Foundation Imagining then went to work on it, but couldn't devote enough time, so Koji Kuramura spent 36 hours of his own time bringing it to life.
The windows were the issue. The producers didn't want a ship that didn't have noticeable windows. The designers were furious. Added to this, the inclusion of the future ship created a noticeable plot hole in a very early episode of Enterprise. For that reason, the very ho-hum Trip Gets Pregnant episode has become the show that abandoned a new design for cheap re-use of an old one. At least it became a cautionary tale.