As the weather improved, Don Juan decided not to coast round the Gulf by Taranto, but to lay his course from Cape Colonna for Cape Santa Maria (the heel of Italy), and then across the opening of the Adriatic to Corfu. A frigate was sent to inform D'Avalos of the change of plans, and the armada, helped by a favouring wind, stood out to sea and for a while lost sight of land. It was known that the Turkish fleet had concentrated in or near the opening of the Gulf of Corinth. It might also have put to sea, and Don Juan took precautions in view of a possible encounter during his voyage. Cardona, with his seven swift galleys of the vanguard, was directed to keep twenty miles ahead during the daytime, closing in to a distance of only eight miles at sunset, and increasing the interval again at dawn. The three squadrons of the main body appear to have been formed each in line ahead, the leading ships, those of the admirals, at the head of each squadron, with such lateral intervals between the columns that line of battle could be formed, by the ships coming up to right and left of their flagships. Santa Cruz with the reserve acted as a rearguard, and was to assist any vessel that might be in difficulties. The rear ship of each squadron was to display a large lantern at the mast-head after dark. The admiral's ship was distinguished by three large lanterns. Forty galleys were detached to bring reinforcements of infantry from Taranto and Gallipoli. Four swift galleys under the command of Gil d'Andrada were sent on in advance to obtain information of the Ottoman fleet. From Cape Santa Maria the course was set for the Ionian Islands. On the morning of 24 September, through the driving rain that accompanied a heavy thunderstorm, the look-outs of the vanguard could distinguish the chain of islands north of Corfu, the islets of Merlera, Fano, and Samothraki, which with the reefs that almost connect them form a natural breakwater. The wind and sea were rising, and the fleet anchored inside the shelter of the islands and reefs. It was not until 26 September that it reached at length the harbour of Corfu. It had taken ten days to complete a passage that the tourist from Messina to Corfu now covers in a single day.