If the need ever arises, it should be simple to activate the device. It is powered by a series of Welkynd Stones. It should target and destroy attacking ships of its own volition.
In addition to the stone in your possession, I'll keep one in the chest at my home. The final stone is at Marrayna's tavern. I know, I know, it's just a dalliance. But I wanted to give her something nice.
Just place the stones in the right sequence of sconces, and it will activate. The sequence is —