HMS Colossus was a 80-gun second rate Vanguard-class ship of the line built for the Royal Navy in the 1840s.

The Vanguard class was designed by Sir William Symonds, Surveyor of the Navy, with each ship built with a slightly different hull shape to evaluate their speed and handling characteristics.

[2] The Vanguard class ships of the line were armed with twenty 32-pounder (56 cwt)[Note 1] cannon and two 68-pounder carronades on her lower gundeck, twenty-eight 32-pounder (50 cwt) cannon and another pair of 68-pounder carronades on the upper gundeck.

On trials the engine produced 1,458 indicated horsepower (1,087 kW) which gave the ship a speed of 9.3 knots (17.2 km/h; 10.7 mph).

[3] Colossus was ordered from Pembroke Dockyard on 18 March 1839 and laid down in October 1843.