| Category | Seam Barges |
| Class | Seam Barge |
| Builder | |
| Commissioned | unknown |
| Owner | unknown |
Before the Second Epoch, going back through a Seam Portal was impossible for all but the Earthen. This changed with the advent of specialized Mhornar Skree called Nalgu Skree. This ship type, very expensive to build and operate, can pass through Seam Portals in either direction. They get this power to go upstream from a special engine containing the energies of a very powerful earth elemental.