How Thomas Hardy extended Nelson's command

Did Nelson's earlier injuries impair his ability to command at Trafalgar?

Not substantially. Hardy supplied an observant and capable flag captain, with his height jokingly treated as another advantage.

Nelson's earlier injuries are judged to have had little effect on his ability to command. Hardy was a competent officer who could observe the battle, interpret what he saw, and supply information when Nelson needed it. His height also prompts a joke about providing the short admiral with a particularly tall pair of eyes. Nelson, in return, was preparing Hardy for senior command.