Alien Submarines
The USOs used by the aliens are big, blocky, shapes which resemble sea creatures and lack most forms of aerodynamics. They are able to dive and fly at breakneck speeds through the power of Zrbite and the resiliency of Aqua Plastics. USOs come in a variety of forms ranging from the tiny Survey Ships right up to the massive Dreadnoughts.
USOs are the aliens' sole method to move around Earth, and collect resources, so in theory, it would be possible to halt the alien advance if X-COM could maintain absolute naval superiority. Earth's forces do not initially have the resources required for such a task, and even if it becomes possible, the aliens have an vast resource supply and will not be set back by a war of attrition. In addition, alien undercover agents will continue to erode Earth's defenses from the inside.
Despite this, commanders should still down as many USOs as possible. At the very least, it may slow the aliens down some.
UFO Types
The aliens use special submerging vehicles known as USOs. The USOs deployed by the aliens range in size and the mission profiles they are most commonly seen on, some are also much more common to certain of the alien races encountered.
Very Small UFOs
Survey Ship - Very Small USO. Primarily used for research.
Small UFOs
Escort - Able to fill a variety of roles.
Cruiser - Slightly larger than the Escort. Very versatile.
Medium USOs
Large USOs
Fleet Supply Cruiser - Large-sized USO for tranportation of aliens, food, and other supplies.
Battleship - Large USO used to unleash assault teams and Terror Units on residential areas.
Very Large USOs
Dreadnought - Very Large USO used to intimidate Earth's peoples and leaders, and to assault X-COM bases, along with a variety of other roles.
Quick Comparision Table
Craft | Size | Max Speed | Weapon Power | Weapon Range* | Damage Capacity | USO Downed Points | USO Destroyed Points |
---|---|---|---|---|---|---|---|
Survey Ship | Very Small | 2,000 | 0 | 0 | 60 | 50 | 100 |
Escort | Small | 2,800 | 30 | 104 | 300 | 75 | 150 |
Cruiser | Small | 2,600 | 25 | 280 | 300 | 125 | 250 |
Heavy Cruiser | Medium | 3,800 | 60 | 160 | 450 | 250 | 500 |
Hunter | Medium | 4,500 | 50 | 144 | 500 | 250 | 500 |
Fleet Supply Cruiser | Large | 3,400 | 70 | 304 | 2000 | 400 | 800 |
Battleship | Large | 4,200 | 120 | 400 | 1400 | 500 | 1000 |
Dreadnought | Very Large | 4,800 | 140 | 480 | 3400 | 700 | 1400 |
* The figures given in the in-game UFOpaedia are a factor of 8 too high, relative to Sub Armament ranges.