The class comprised Medusa, the first Dutch warship with screw propulsion, and Prinses Amelia.

Only in early 1852 a commission of naval officers was appointed to look into the possibilities of auxiliary steam power.

[3] In early November 1852 the plans had been expanded to build three ships in Amsterdam and one in Flushing.

To the contrary the Medusa's were called by their sailing equivalent 'corvette', or corvette with auxiliary steam power.

In detail, it was about a quarter bigger because its length was increased to mount the steam engine and to store coal.

The machines for Medusa were made by Fijenoord shipyard in Rotterdam, then often referred to as NSBM.

[8] There is a note that the initial armament of Medusa had to be lightened after sailing trials ended badly.

[9] In 1853 the Medusas were ordered to have on the battery deck: 4 grenade guns of 20 cm No 2 and 12 long 30 pounders No 3.

This was not the case, because at the time the grenade guns were officially designated 'by the weight of the solid shot they fired'.