Combatants captured alive (or dead) are often taken below deck to be tortured and their agony used to power the ship's Essence engine. Pain is transmitted along the soulsteel ribs of the ship's structure.
A Thousand Lives of Torment sometimes perform necromantic rites so the souls of those killed turn into ghosts and are bound there in soulsteel manacles or within the fabric of the ship so their agony can endure after their death.
Is the ship a shadowland or becoming the centre of a shadowland? When 10,000 souls are delivered will it become a manse?
In the bowels of the ship is a miserable hold where captives are held either to be eaten by the crew or to power the ship. Sometime before a battle the deathknight will kill some of the captives, then bind their spirits so they can be used as hungry ghosts.
The vessel literally is a ghost ship, made from people's souls who's agony was so terrible it took on physical form and with shades bound to it's structure.
Ths ship can't hold out water (at least most of it) but actually sinks and it's soulsteel hull is far too strong to be seriously damaged. The only way to sink it is to damage or destroy the hearthroom.
