Uncharted Waters Cash (UWC) is a Virtual Currency that you can purchase to enhance your gaming experience in Uncharted Waters Online (UWO), provided through the Vertigo Games portal, Papaya Play.
You can spend UWC in-game at the "UWC Shop". (To access the Shop, click the red button located at the top right corner of the screen)
Also, you can spend UWC to purchase "Treasure Cove Keys" for opening special Chests that contain a lot of items and ships which are not obtainable in game at:
https://uwo.papayaplay.com/treasurecove/main.do