Technical shortcomings that changed a naval battle

What are striking examples of technical difficulties limiting performance in battle?

The examples are Spanish cannon ill suited to sustained fighting at sea and South Dakota's electrical failure at Guadalcanal.

The Spanish example concerns guns intended largely for the army being transported, leaving them poorly suited to the sea battle described. That limitation is credited with giving the English fleet greater freedom of action. A separate example concerns South Dakota's electrical problems during the naval battle of Guadalcanal. Washington and Admiral Lee provide the contrast within that battle: a major systems failure disabled one ship while another continued to fight.