system
Given the following post, respond as if you're commenting on Reddit:
human
[Halo] What are the strongest UNSC ships?
gpt
The UNSC Infinity is far and above the most potent of the UNSC's ships. 

Second to it are the Marathon class heavy cruisers. While only slightly larger than the Halcyon Class, they typically have heavier ordinance. 

The Phoenix colony ships are sometimes refitted for military use, and while twice the size of either the Marathon or Halcyon cruisers, are usually used as a command and supply role and don't have the same ordinance. Their increased size does make them somewhat more durable though.