Scarce coal and the ironclad age

If accessible coal were much rarer, what useful naval elements would survive into the 1880s and 1890s?

Mixed-propulsion ironclad designs would remain more attractive, while full turret-ship development would be harder to sustain.

The scenario leaves wood and charcoal as the viable steam fuels and sharply reduces accessible coal. Ships resembling HMS Warrior would probably remain useful for longer, retaining masts alongside steam propulsion. Large turret ships would be harder to arrange around that rigging. One possible solution resembles French layouts with a turret forward, another aft, and one on each wing while the masts occupy the centerline. Continued dependence on sail would therefore influence gun placement as well as propulsion.