Below is the news item published in the London Gazette on the 11th of July, 1848
Admiralty, 11th July 1848.
STEAMERS' LIGHTS.—To PREVENT COLLISION.
By the Commissioners for executing the Office of Lord High Admiral of the United Kingdom of Great Britain and Ireland, &c. &c. Whereas under and by virtue of the Act of Parliament, passed in the tenth year of the reign of Her present Majesty, intituled " An Act for the regulation of steam navigation, and for requiring sea going vessels to carry boats," we hereby require, in pursuance of the said Act, that lights shall be exhibited by all steam vessels, except in the river Thames, above Yantlett Creek, between sun-set and sun-rise, of such description and in such manner as hereinafter mentioned, that is to say :
When under Weigh.
- Bright white light, at the foremast head.
- Green light, on the starboard side.
- Red light on the port side.
When at Anchor.
A common bright light.*
The following conditions to be observed, viz.
- The mast head light to be visible at a distance of at least Jive miles in a clear dark night,
and the lantern to be so constructed as to shew a uniform and unbroken light over, an arc of 'the horizon of twenty points of the compass, viz. from
right ahead to two points abaft the beam on each side of the ship.
- The coloured side lights to be visible at a distance of at least two miles in a clear dark night, and the lanterns to be so constructed as to shew a uniform and unbroken light over an arc of the horizon of ten points of the compass, viz. from right ahead to two points abaft the beam on their respective sides.
- The side lights to be moreover fitted with inboard screens, of at least three feet long, to prevent them from being seen across the bow. The screens to be placed in a fore and aft line with the inner edge of the side lights.
*4. The lantern used when at anchor to be so constructed as to shew a good light all round the horizon.
*** Diagrams, illustrative of the above plan, and instructions, as to the proper mode of fitting the lights on board steam vessels, will be furnished to parties applying for them.