Victorian ironclads produced many celebrated false starts

Was there a celebrated warship innovation that later turned out to be a false start?

Yes. Victorian ironclad development produced several, especially central-battery experiments and ships such as HMS Captain and HMS Inflexible.

The experimental Royal Navy of the 1850s through the 1890s produced several apparent breakthroughs that proved less durable than Dreadnought. Central-battery and other transitional ironclads promised decisive improvements while designers were still learning how armor, guns, sail, steam, and stability interacted. HMS Captain and HMS Inflexible exemplify the period's appetite for supposedly transformative arrangements whose limitations became clearer in service or, in Captain's case, catastrophically. Experimentation remained necessary, but a ship proclaimed as the next great leap could instead reveal which design path to abandon. Dreadnought's success stands against this long record of Victorian false starts.