By Shane Winser
Last updated 2011-02-17
The length of the Great Eastern was 680ft, with a breadth of 120ft over the paddle wheels. Its gross tonnage was 18,914 tons, whilst its displacement was over 27,000 tonnes. The nominal horsepower of the paddle-wheel engines was 1,000, and the screw engines generated 1,600hp.
The paddle-wheels were 56ft in diameter, and 13ft wide. The four-bladed screw propeller was made of cast iron, 24ft in diameter, with a 37ft pitch, and it weighed 36 tons. When both were operating the ship moved at approximately 12 knots.
Apart form the innovation of the double hull, the other extraordinary feature of this design was the degree of standardisation that Brunel achieved. Standard plate sizes and thicknesses (1in, 3/4in, 1/2in), bar sizes (4in x 4in by 5/8in), rivet diameters (7/8in) and fixing arrangements (single rivet seams, double rivet butts) were used throughout.
No ship of comparable size has been built of so few standard elements. Despite the increase in structural weight that such standardisation generally implies, the ratio of hull structure weight to displacement was less than a quarter.
As Scott Russell described the ship,
'The lines are perfect wave lines; the middle body, 120ft, is perfectly straight and parallel. The 120ft of the middle body gives the ship roominess and ease in a seaway ...The vessel exhibits the points which I consider good in the midship section of a large ocean steamer; the widest part of the midship section is at 28ft draft. There is a dead flat on the floor, extending 36ft of the width of the ship; and the bilges are very nearly circular. From the water-line the sides tumble home gently to a diminished breadth of 76ft at the gunwhale of the upper deck'.