Troll Ships

Troll Ships are a design entirely unlike anything used by the navies of Earth. The superstructure is carved from rock, and the entire rest of the ship (made from wood) lies below the waterline. Projectiles fired at these ships will almost always harmlessly bounce off, and even a perfect hit is unlikely to cause any significant damage. However, this enormous durability comes at a major cost - troll ships have the worst manoeuvrability of any race's ships, and there is little space to mount large weapons; duels between troll ships persist until one side runs out of ammunition or decides to retreat.