Construction Corvette is the T1 naval constructor. They are a good builder in terms of build power and speed - even a single one of these assisting the shipyard almost doubles its output. On top of Commander’s build list, they are able to produce more advanced T1 defences, like the Floating Heavy Laser Turret, and give access to the T2 Shipyard. Each one adds 50 to your metal and energy storage capacity.
Use them for assisting the lab and quickly expanding, claiming underwater metal spots with underwater metal extractors.