Here is how you get the Voyage of Despair how to Pack-A-Punch in Black Ops 4 Zombies and the steps that you need to complete.
What you need to do first is activate 4 Pack-A-Punch pedestals around the map and below you can see the Pedestal locations and obtain the sentinel artifact:
- Cargo Hold
- Turbine Room
- Poop Deck
- Grand Staircase Bottom Floor
Once you find all the four different locations you will be able to pack a punch machine.