The Tech Tree is how you get from one ship to the next, more powerful ship. There are different branches for different types of ships, and defined Tiers that, theoretically, allow you to compare ships of a different Class or Nation. Theoretically, two ships of the same Class, at the same level of the Tech Tree, should be able to compete moderately well against one another. This page provides information on World of Warship's Tech Trees, how they work, what ships and Nations are in them, etc.