THE INVINCIBLE. The Invincible, of 74 guns, bearing the flag of Rear-Admiral Totty, and commanded by Captain Rennie, sailed from Yarmouth on the morning of the 16th of March, 1801, to join the fleet of Admiral Sir Hyde Parker in the Baltic. The master and the pilot were both considered very skilful mariners of those seas, and their orders were to navigate the ship into the North Sea, and to put her in the way of joining the fleet to the northward, as soon as she had cleared all the shoals. About half-past two o'clock, P.M., of the same day, the Invincible, going at the rate of nine knots an hour, struck violently upon a sand-bank, and before the sails could be furled, she was fast aground in little more than three fathoms water. The pilot and master assured Captain Rennie that there was no danger, and that the ship must have struck upon a lately formed knowl. In order to lighten her as much as possible, the yards and topmasts were struck, and some of the provisions thrown overboard, and then strong hopes were entertained that she would float off the bank with the next tide. During this time she lay tolerably quiet, and the water gained but little upon the pumps. Every means was used to draw the attention of vessels passing near--guns were fired, and signals hoisted; but they remained unanswered until about five o'clock, P.M., when a cutter was observed scudding towards Yarmouth Roads, as if to inform Admiral Dickson of the situation of the Invincible. As the ship remained easy, neither the officers nor men suspected that the danger was imminent, and they performed their duty with the same regularity as if the ship were proceeding under ordinary circumstances. All went on well until about half-past five, P.M., when the wind freshened, and the vessel began to beat the ground with such violence, that it was thought necessary to cut away the masts. The ship at this time dropped from three and a half into seventeen fathoms. She was then brought to with her bower anchor, and there appeared every probability of her getting safely off till about nine o'clock, when the flood-tide was making; she then lost her rudder, became unmanageable, and was driven back upon the rock. Fortunately a fishing-smack had come near the Invincible a short time before, and Admiral Totty learnt from her master that the ship had struck upon Hammond's knowl; whereupon the admiral requested that the smack might be anchored as near as possible, so as to be ready in case of emergency.