 The existence of five admiralty colleges, each with its own policies on ship construction and armaments, each favouring its local commanders and with variable levels of efficiency, and the reluctance of Johan de Witt to appoint Orangist officers, all led to difficulty in creating a unified navy.At Lowestoft, the English Fleet was commanded by James, Duke of York, who was heir presumptive to his brother Charles II as well as Lord High Admiral of England.In view of the significant number of casualties among senior English officers and noble volunteers, including three killed next to the Duke, Charles insisted that his brother should no longer command at sea.