Still the survivors remained in good spirits. There was for the present all possible harmony between army and navy,[144] and the losses could to some extent be made good by embarking the four independent companies which lay in garrison in Jamaica. But meanwhile the French fleet was concentrated off the coast of Hispaniola, and until it should be dispersed the commanders dared not undertake any operations against the Spanish Main. It is true that France and England were not at open war; but this, as shall presently be seen, was no reason why the fleets and armies of the two nations should not fight each other. When, therefore, the fleet at last sailed from Jamaica on the 7th of March, Vernon was fully resolved to attack the French if he should fall in with them.[145] He was, however, relieved of any such responsibility. Sickness had driven the French fleet back from the Caribbean Sea to Brest, and the British were free to go whither they would. It was thereupon decided to attack Carthagena without delay, for though Cathcart's instructions gave Wentworth the option of first attempting Havana, yet the Cuban port was considered to be too well defended, whereas Carthagena would, it was hoped, fall an easy prey. The fact was that Vernon had set his heart on Carthagena, and he found little difficulty in carrying his point. [Sidenote: March 4/15.] On the 15th of March, accordingly, the fleet anchored at Playa Grande, two leagues to windward of Carthagena, and the English commanders could judge of the work before them. The city of Carthagena lies at the head of an inland lake, which extends at its greatest length for some seven miles north and south. To this lake there are two entrances, of which the eastern, known from its narrowness as the Boca Chica or Little Mouth, alone was practicable for line-of-battle ships. The western side of the Boca Chica was defended by three forts--St. Jago and San Felipe at the entrance from the sea, and Fort Boca Chica, a far more formidable work, half way up the passage. On the eastern side a fascine-battery had been thrown up at the entrance, while another stronghold, Fort St. Joseph, sealed up the inner end. To force the Boca Chica so as to admit the fleet to the harbour was the first task to be accomplished by Wentworth and Vernon. [Sidenote: March 9/20.] [Sidenote: March 11/22.]