The Roberts-class is a monitor warship, designed with the sole purpose of bombarding coastal regions. It is very effective at this job, carrying a pair of battleship guns on an otherwise small hull. Though only two were constructed in WW2, Oceanykan sailors working for the Allies managed to obtain the design's schematics, and successfully reproduced them back home for sale.
As a monitor, the Roberts-class is extremely well armoured and armed for a ship of its type, limited to coastal waters. However, it is very slow, and will fare badly against anything the size of a cruiser or larger. Its true excellence lies in ambushing capital ships and reducing coastal fortifications or settlements to the stone age.