Little had been done to demonstrate the power of the screw propeller, which for some unfathomable reason was considered to be suitable only for small vessels. However, after the construction of the _Great Britain_ had been commenced, the steamer _Archimedes_, fitted with Smith’s screw propeller, arrived at Bristol during her tour of the ports and demonstrated once and for all that the screw propeller could be used in seagoing vessels, and that, provided engines of sufficient power were installed, the screw propeller was more suitable for large hulls built to make ocean voyages than the best paddle-wheels then designed. But many years were to elapse before the shipping industry generally accepted this view. The advantages of the screw, as proved by the _Archimedes_, were not, however, lost upon the enterprising directors of the Great Western Steamship Company, and they did not hesitate to order the designs of the _Great Britain_ to be altered so that she could be fitted with a screw instead of paddles. She was not built on a slip whence she might have been launched into the river, but in an excavated dock, and when she was afloat in the dock it was found that she was too big to be got out of it. That is to say, that having been fitted with her engines while still in dock, their weight immersed her to such an extent that she could not float out. This was owing to the dock officials’ delay in finishing alterations to the dock entrance, and not to any mistake or negligence on the part of the steamer officials. She was water-borne on July 19, 1843, and was christened by Prince Albert. The floating was attended by vexatious mishaps. The _Great Britain_ was attached by a hawser to the tug _Avon_, which was outside the dock, but at the critical moment the hawser broke. The bottle of wine thrown at the ship by the Prince fell several feet short. He threw another bottle of champagne, which struck the bows, and the wine and broken glass fell upon the men below, who were pushing against her sides to keep her off the dock walls. [Illustration: MODEL OF THE “GREAT BRITAIN.”] Her figure-head consisted of the royal arms, flanked with a beehive, two cog-wheels, a dove, square, and the caduceus of Mercury in bronze on a white ground, with a scroll above and below. Her anchor was on Porter’s newly invented patent, which had been satisfactorily tested in the Navy for three years. Her designer and builder took no chances. She was put together as strongly as possible, and it was well that this was so, for in her eventful career she was altered so frequently and so much that had she not been excellently put together she would very soon have succumbed to ship surgery. Her keel was formed of iron plates varying from three-quarters of an inch thick in the middle to one inch at the ends.