Silurian battlecruiser

Silurian battlecruisers were used by the Silurians and Sea Devils during their reign of the Earth in pre-historic times. They're built using organic material and not metal.

The battlecruisers were the equivalent of human submarines and were designed to dock with the Sea Devil colonies on the sea bed. The battlecruisers were also equipped with a particle suppressor as a defensive weapon. It is also possible that, if there were more than one Myrka, battlecruisers had a holding pen for the creatures.

One known battlecruiser was that of Icthar and two other Silurians who, in 2084, used it to collect the Sea Devils of Elite Group One and then attack and invade Sea Base 4. (DW: Warriors of the Deep)