It was during the week following the detachment to Nelson that St. Vincent left the fleet, and that Keith made the false move which has been so severely blamed. It appears to the author, from all the information accessible to him, that Keith took this step wholly independent of St. Vincent's special orders, which are alleged as controlling him. He acted in deference, partly, to the general orders given before turning over the command, and partly to his own views of the situation.[283] These seem to have differed from those of St. Vincent, who laid most stress on disabling the enemy's fleets; whereas Keith was dominated by the fear of losing Minorca. This feeling led him to deviate from the order to cruise off the Gulf of Rosas, as it also led him soon after, on two occasions, to direct Nelson to detach ships for the defence of the island; which Nelson, with very doubtful propriety, refused to do.[284] Minorca, in this case, very appositely illustrates the embarrassment of a fleet upon which an important seaport wholly depends for security. In the present instance the beating of the French fleet and the protection of Minorca introduced two apparently divergent motives, which became personified in St. Vincent and his lieutenant. The former saw the best protection to the island to be in beating the fleet; Keith subordinated the latter to the former. With St. Vincent agreed Nelson's simple but accurate view of naval strategy: "I consider the best defence for his Sicilian Majesty's dominions is to place myself alongside the French."[285] Keith, on the other hand, in a somewhat later letter, expresses almost pathetically the embarrassment caused by his inferior strategic insight. "It is very hard I cannot find these vagabonds in some spot or other, and that I am so _shackled_ with this defenceless island."[286] Properly every seaport should be able to hold out for a length of time, longer or shorter, according to its importance, entirely independent of the fleet. The latter will then be able to exert its great faculty, its mobility, unfettered by considerations of what is happening at the port. For so long the latter is safe; meanwhile the fleet may be absent. The best coast-defence is a navy; not because fortifications are not absolutely necessary, but because beating the enemy's fleet is the best of all defences.