The duties and responsibilities which devolved on the Building Committee--Captain Claxton, Mr. Guppy, and Mr. Brunel--were most arduous. To design and construct a steam-ship larger than any that had, up to that time, been launched, to make this ship of a material which had but lately been introduced into shipbuilding, and which had never before been employed on a large scale, to adapt to this ship a novel form of propeller which had not previously been used save in a merely experimental steamer, and to build in a newly opened manufactory marine engines of a much greater size than any that had hitherto been contemplated, and of a totally different character, was indeed a bold enterprise. Mr. Brunel had, as has been shown, recommended the Company not to undertake one part of the work, that, namely, of the manufacture of the engines, which he thought would have been better entrusted to the most experienced engine builders. But although the Directors had acted contrary to his advice, this circumstance in no way diminished the zeal with which he and his coadjutors entered upon their task. A short statement of the principal dimensions of the vessel and engines is given in a note to this chapter; but some of the more remarkable features in the design may be mentioned here. In the construction of the ‘Great Britain,’ the same care which had been spent in securing longitudinal strength in the wooden hull of the ‘Great Western,’ was now given to the suitable distribution of the metal. Over the transverse angle iron ribs at the bottom of the ship were laid ten deep longitudinal beams (see woodcut, fig. 13, _a_), which, over the greater part of the bottom of the ship, were covered with an iron deck (_b_) riveted to their upper edges by angle irons, thus forming a cellular structure which added greatly to the strength of the ship. It does not appear that this deck was designed to be watertight, so that it did not form the same security against accident as the inner skin of the cellular structure which Mr. Brunel afterwards adopted in the ‘Great Eastern.’ The upper part of the sides of the ship, in the middle of her length, were carefully designed so as to give her longitudinal strength. The side plates were thickened, and were riveted to iron shelf-plates three feet broad (_c_); and two bands of iron, six inches wide and one inch thick, with the joints strengthened, ran along the top of the ship’s side. There were bands of iron riveted to the shelf-plate, and iron deck beams crossed diagonally under the planking of the upper and main decks. Also at the junction of the ship’s side with the shelf-plate there ran longitudinally a tie of Baltic pine timber, 340 square inches in section (_d_); this being well secured to the shelf-plate and ribs, added considerably to the strength of this portion of the hull. The ship had five watertight bulkheads, and was thus separated into six compartments. [Illustration: _Scale of feet_.