What happens when battle fleets cross technological eras

The time-travel question extends from land forces to fleets separated by decades of naval development. Nelson's Trafalgar-era ships would overwhelm a substantially earlier force because the later fleet brings much greater effective firepower. A Jutland-era battle fleet appearing at Trafalgar would create an even more extreme mismatch against the Franco-Spanish line. The scenario is deliberately counterfactual, but it makes the cumulative effect of gunnery, propulsion, protection, and command systems easy to grasp.