Honestly, I'm struggling to figure out what you're talking about. The Oberth is a T1 sci ship, and it doesn't have a cloak. In fact, only two federation ships have a cloak, and they're both T5 ships, AND the cloak is limited to those two ships. Besides that, having a cloak on fed ships would be against the Algeron Treaty, and is completely non-canon.
No ship have a PHASE cloak, please research a little on the matter, you will find that only the Pegasus had an experimental one, that later was used by the Enterprise D to exit the asteroid.
Also, the Pegasus class would require 4 nacelles.