Rear Thrusters are basic thrusters designed to increase forward speed.
Strategy and Setup
Rear Thrusters are used on most ships because forward speed is extremely important for kiting tactics, in which ships with superior range fly away from and fire back at enemies that have shorter range, often destroying them before they could catch up. Likewise, this thruster is also necessary on short-range ships to catch up to longer-ranged ships before being destroyed.
Rear Thrusters are less ideal on battleships and destroyers because they reduce turning speed, allowing enemies to easily fly into their blind spot and destroy them without taking any shots in return.