Fortunately in the Pacific Thether they were nowhere as important as in the Atlantic, hence youc ould play a whole career without participating in a wolfpack and still be doing a realistic one (Like O'Kane in the USS Tang for example, he acted with other submarines but never in coordinates attacks, just in patrol search operations and only very loosely).
For a german U-Boat game, however, the lack of wolfpacks ia a TRAGEDY
Yes you can still play early war with a Type II, a type VII in the Mediterranean, or long range patrols with Type IXs, operating alone. But facing a well escorted convoy in the North Atlantic alone and without the help of a wolfpack is pure madness, and utterly devoid of what happened in real life.