Editing SS Great Britain (section)

===General description===
[[File:SS Great Britain diagram.jpg|thumb|Sketch of ''Great Britain''. The lower image shows the internal arrangement of her decks and machinery.]]
When completed in 1845, ''Great Britain'' was a revolutionary vessel—the first ship to combine an iron hull with screw propulsion, and at {{convert|322|ft|m|abbr=on}} in length and with a 3,400-ton displacement, more than {{convert|100|ft|m|abbr=on}} longer and 1,000&nbsp;tons larger than any ship previously built. Her [[beam (ship)|beam]] was {{convert|50|ft|6|in|m|abbr=on}} and her height from keel to main deck, {{convert|32|ft|6|in|m|abbr=on}}. She had four decks, including the [[spar deck|spar (upper) deck]], a crew of 120, and was fitted to accommodate a total of 360 passengers, along with 1,200&nbsp;tons of cargo and 1,200&nbsp;tons of [[coal]] for fuel.{{sfn|Claxton|1845|p=3}}{{better source|date = November 2024}}

Like other steamships of the era, ''Great Britain'' was provided with secondary sail power, consisting of one [[square-rig]]ged and five [[schooner]]-rigged masts—a relatively simple sail plan designed to reduce the number of crew required. The masts were of iron, fastened to the spar deck with iron joints, and with one exception, hinged to allow their lowering to reduce wind resistance in the event of a strong headwind. The rigging was of iron cable instead of the traditional [[hemp]], again with a view to reducing wind resistance.{{sfn|Claxton|1845|pp=19–20}} Another innovative feature was the lack of traditional heavy bulwarks around the main deck; a light iron railing{{Sfn|Fox|2003|p=152}} both reduced weight and allowed water shipped in heavy weather to run unimpeded back to sea.

The hull and single [[chimney|funnel]] amidships were both finished in black paint, with a single white stripe running the length of the hull highlighting a row of false gunports. The hull was flat-bottomed, with no external [[keel]], and with bulges low on each side amidships which continued toward the [[stern]] in an unusual implementation of [[tumblehome]]—a result of the late decision to install propeller engines, which were wider at the base than the originally planned paddlewheel engines.{{sfn|Fox|2003|p=149, 152}}

Brunel, anxious to ensure the avoidance of [[Hogging and sagging|hogging]] in a vessel of such unprecedented size, designed the hull to be massively redundant in strength. Ten longitudinal iron girders were installed along the keel, running from beneath the engines and boiler to the forward section. The iron ribs were {{convert|6|x|3|in|cm}} in size. The iron keel plates were an inch thick, and the hull seams were lapped and double [[rivet]]ed in many places. Safety features, which also contributed to the structural strength of the vessel, included a [[double bottom]] and five watertight iron [[bulkhead (partition)|bulkheads]].{{sfn|Fox|2003|p=150}}{{sfn|Claxton|1845|p=5}} The total amount of iron, including the engines and machinery, was 1,500&nbsp;tons.{{sfn|Claxton|1845|p=18}}