How US dynamite-gun ships aimed fixed weapons

How did American dynamite-gun ships aim weapons that appeared to be fixed in the hull?

They steered the whole ship onto the target and then fired along the hull's fixed line of aim.

The fixed dynamite guns could not train independently across an arc. Their crews aimed by steering the entire ship until the hull pointed the weapons at the target. Other historical vessels also used fixed or nearly fixed armament in this way. The arrangement was workable, but it tied fire control directly to ship handling and was less flexible than a trainable mounting.