ten o’clock
But if the breeze died away , the ebb would carry them away from the shore , and they would be compelled to anchor and wait for the next tide , a serious consideration , and one that filled John Mangles with anxiety . Still he hoped to succeed . The wind freshened . The tide had turned at ten o'clock , and by three they must either make the land or anchor to save themselves from being carried out to sea . They made a good start . Little by little the black line of the reefs and the yellow banks of sand disappeared under the swelling tide . Extreme watchfulness and perfect skill were necessary to avoid these submerged rocks , and steer a bark that did not readily answer to the helm , and that constantly broke off .