Why major naval disasters rarely exclude politics

What is the worst thing that happened to a navy without being caused by its own politicians?

Almost every fleet-scale disaster can be traced partly to political decisions; narrower cases such as the Falkland Islands or River Plate come closest to a primarily naval failure.

Copenhagen, the Spanish Armada, Tsushima, the Medway, Coronel, the Falkland Islands, River Plate, and Bismarck all arise as possible answers. The Spanish-American War and the Glorious First of June also lead the discussion back to government decisions about missions and rules of engagement. In the Armada's case, appointments constrained by noble status shaped the command structure as well as the fleet's task. The Medway example connects the vulnerability of the fleet to Charles II's attempt to save the cost of activating it. Coronel illustrates the consequences of dispersing ships to meet competing demands instead of concentrating enough strength. Von Spee's decision to attack the Falkland Islands is a stronger candidate for an operational mistake, although the forces hunting him still limited his prospects. Langsdorff's decision to seek further successes near the River Plate is another candidate, but it concerns a single ship. Bismarck's possible return after the action with Hood raises the competing requirement to complete an assigned mission. Narrow operational mistakes remain possible exceptions to an otherwise close connection between fleet disasters and political decisions.