Twiss’ Black Book of the Admiralty Vol 4 Page 373 footnote 2:

[I]n the Code of Riga of A.D. 1270, …. , there is special provision to this effect: “that if two vessels come into collision on the sea in a dark night, and the one has a light set and the other not, the damage done by the vessel without a light shall not be made good by the other, but the damage done by the vessel with a light shall be made good by the other.”


The Sailor’s Defence!!

“Please your Magistrates worship and glory – he run foul of my Larboard Side…..”

Until the invention of the steamship there were no regulations for the avoidance of collisions at sea. There were, of course, unwritten laws and the custom was that the ship sailing with the advantage of the wind would give way to the ship whose course was less favoured by the wind.

However, when two ships were on crossing courses and both were close hauled to the wind an arbitrary rule was required if one was to keep out of the way of the other.

The rule which developed was that the ship on the port tack would give way to the ship on the starboard tack.

The origin of this rule is said to lie in the custom that early ships carried their steering oar on the starboard side of the ship. When two ships were tacking on crossing courses the ship which was presenting her starboard side to the other would alter course first in order to show her port side and thereby protect her steering oar from the other ship.

In any event, it became a law of the sea that a sailing ship on the port tack would give way to a sailing ship on the starboard tack.

She would do this by putting her tiller up wind and altering so as to pass port to port. She would have to alter sufficiently to keep well clear of the port side of the other ship and it seems that the sailors in the other ship would become very “touchy” if she came too close to their port side.

This is illustrated in a caricature made by George Moutard Woodward in 1807 entitled The Sailors Defence  where the defence    “he run foul of my larboard side”     appears to be an allusion to the port tack rule.

The rule was later adopted for steamships on crossing courses and when side lights were introduced the red light for danger was placed on the port side to indicate to the other ship that she should keep clear. A ship was perceived by mariners to be in some legal difficulty if she crashed into the red side light of the other ship. It was for this reason during the Cod War that Icelandic tugs would choose to ram the starboard side of Royal Navy frigates with their own port side.

It is something of a paradox that the custom of carrying the steering oar on the starboard side may have led to the law that one is required to keep clear of a ship showing her port side.



Report of Select Committee on Steam Navigation 1831

When paddle-steamers first appeared in the rivers and estuaries, the practice which was naturally adopted for passing each other is described by Captain K. B. Martin in his evidence to the Parliamentary Select Committee on Steam Navigation in 1831 as follows:-    

88. What are you? - I am in the command of the City of London steam packet, and deputy harbour master at Ramsgate, during the winter months.

209. You are out in your vessel at night? - Yes.

210. What is your custom about lights? - My custom would be to place a very good lantern at the foremast head; it must have a back to it, or it would intercept the sight; and one under each paddle box.

211. Is that always done? - I always do it, and then any vessel ahead of us sees that we are coming.

212. Do you know that other vessels do it? - I saw yesterday evening five vessels in the river, and every vessel had a lantern at the mast head.

213. Is that a particular plan of your own, or is it an order from your owners? - They order me to fix lights, but I exercise my own discretion as to the manner of fixing them.

214. Have you ever seen Higgins's revolving lights? - Yes, I have seen them tried.

215. Do you approve of them? - Yes, I think they are clever things.

   258.   In passing vessels have you any regulation at all as to keeping sides?

             We have no decided regulation of that kind. It is so easy for vessels to avoid if they see each other; you see which side of the vessel is open, and you go to that side of her because it is easy to go that side. We have this rule in the river; the steam-boat that is going against tide keeps that side of the river where the tide is weakest; the other vessel keeps with the tide.

   259.   And therefore they cross from side to side as they find it convenient?


   259*.  In a dark light as you can have no particular rule similar to what you have stated occurs in the day, what do you do?

             We had no established regulation, I do think that it would be a good thing to have a regulation of that kind.



Royal Commision on Pilotage 1836

Link to National Maritime Museum note on navigation lights


Link to a biography, appearing in British Chess Magazine, of the Welshman whose tombstone in Ostend Ancien Cimetiere claims as the inventor of the tri-coloured system of lights for shipping, Captain William Davis Evans


Parliamentary Paper H. L. 181 of 1839.

Board of Trade Inquiry into accidents of last 10 years and the means of preventing them.



Report of Select Committee on Shipwrecks 1843

Captain E. Chappell R. N. examined by the Chairman:-

  777.      Have you any other suggestions? – The next point, a very great point, and quite within the scope of the Committee’s operations, is to compel every steam-boat to light alike at night. It is a singular anomaly that in the port of Liverpool alone there are 11 modes of lighting a steam-boat.  I have pressed it repeatedly as far as it lay in my power on the public authorities, but never was able to carry it.  I conceive the best mode of lighting a steam-boat is that adopted by the City of Dublin Mail Company, which is one bright light at the mast-head, a red light at the starboard paddle-box, and a bright light on the larboard paddle-box, the object being to enable another ship meeting her at night to tell the exact direction of the other’s head, which way she is going; the anxiety of a steam captain being when he sees another ship to know which way she is steering.

  778.    If such a mode of lighting was not compulsory it might do more harm than good, by leading to error? – It cannot be worse than at present; steam boats will light in every possible variety of fancy.  I saw one last night with a bright light at her mast-head and a light hanging down to the water’s edge.

  779.    In the present mode of lighting they give no idea of the course of the vessel? – Some of them do, some do not; but there is this difficulty, that any vessel meeting another does not know exactly what her arrangement is; but it is so perfectly easy, that I do not imagine that a legislative provision would be objected to by any one.

  780.     Mr Chapman] Are you aware that a similar proposition was made by Captain Beaufort in 1836? – I know I made it in 1836; probably Captain Beaufort made it too.

  781.     Captain Plumridge] Would that be expensive? – No, not at all; they are lighted at present but in every variety of form. I think also the regulation made by the Trinity Board should be made universal, to port their helm when they meet another vessel; but this is not a law, only a regulation. If a law were to be framed, I would recommend that should be included in the law; to make it positive rather than optional, as it is a present, though recommended.

  782.     Both vessels to port their helm? – Yes, that they should look for a ported helm from one another; to make the recommendation of the Trinity Board the law, instead of being a recommendation merely.

  783.     Admiral Dundas] Did the Trinity Board communicate that to the foreign countries? – I do not know; they have it printed in all their books. The strongest proof I can give of the necessity of making it a law is, that when the Trinity Board made the regulation there were parties who did not choose to accede to it. A vessel coming round from Liverpool to London, a steam-boat encountered another steam-boat at the back of the Isle of Wight; one had got the Trinity regulation and the other the Liverpool regulation, which was to starboard the helm; each took her own regulation, and they can in contact, the one the Royal William, and the other the Tagus; they cut down one another.

  784.    Mr Chapman] Are you aware that all the courts of law, since the regulation was promulgated, have given their verdict in favour of the vessel who ported her helm, in preference to the other who did not obey it? – I do know that is the course of the Admiralty Court, but I think it would be desirable to make it a law.

  785.    Admiral Dundas] Do you think it is known in the marine of this country generally? – I think it is not universally known.

  786.    Captain Gordon] Do you propose that it should be compulsory under all circumstances, when you recommend it as law, that a person should always put his helm a-port? – No; I should make it in the terms the Trinity Board has done it.

  787.     How is the Act of Parliament to do that? – That is for the consideration of the Legislature.


Parliamentary Paper No. 568 of 1846 [Microfiche 50.234-235]

This report laid before Parliament the Admiralty’s experiments with Mr Rettie’s Marine Signals which signals were carried on board the steam frigate H.M.S. Comet off Spithead on the 22nd November, 1845. These lanterns appear to be the red and green side lights which we now use.



Parliamentary Paper No. 59 of 1852-53 [Microfiche 57.433-434]

These papers comprise correspondence between Robert Rettie of Glasgow (a member of the Rettie family of Aberdeen, lantern makers and brass founders) and the Admiralty. The correspondence in 1843 requests the Admiralty to test lanterns which Rettie had devised to indicate the ship’s head for the avoidance of collision at sea. The Admiralty were not easily moved but on 12th July, 1845, the lamps were tested at Woolwich and carried on board a naval ship on the river Thames. This led to the official tests at Spithead on board H.M.S. Comet. According to Rettie’s letters, his system of collision avoidance was that enacted for steam ships in the Admiralty Regulations which became law on the 11th July, 1848, under powers contained in Act 9 & 10 Vict c100. 

Rettie was disappointed in his expectations of being employed by the Admiralty in the implementation of his idea and he was dealt with parsimoniously by the Admiralty in relation to the work he had done. A bitter dispute ensued over expenses in the course of which Rettie wrote on the 28th February, 1848, to his M.P.:

“….Now when I showed him my code of signals on the cards, which are also entered at Stationer’s Hall, which goes along with the lamps, and is necessary to explain them, which signal cards Mr Evans, at the last trial at Woolwich, had copied from mine, and made for himself a plan exactly the same, and which cards I then challenged, and told him that if ever I found any more of them, I should make him pay the penalty of 5l. for each copy which is the legal claim for any piratical usurpation of the Act.”


Parliamentary Papers:  Correspondence respecting settlement of the Rule of the Road at Sea and Lights to be carried by Ships 1850-1866

[Microfiche 76.573]

[Microfiche 76.573]

[Microfiche 77.556-557]

[Microfiche 77.557]

[Microfiche 78.468-469]

There was pressure on the Board of Trade from the Cork steamship owners (later supported by the Dublin steamship owners and the Belfast steamship owners) to have the coloured side lights prescribed by Admiralty regulations extended to sailing ships. There was concern at the Board of Trade over the number of collisions being caused by the port helm/right rudder rule especially at night notwithstanding the introduction of side lights for steamers. It was proposed to restrict the port helm rule to the case of ships meeting end-on or nearly end on. There was to be no other rule for two steam ships on a collision course so that in a crossing situation either one would be free to alter thereby relieving the other of the need to act. Stephen Lushington, the Admiralty Judge, in consultation with the Trinity Masters, expressly approved the discretion which this would give to mariners.

The proposed rules were sent to France to obtain agreement and were returned with the proposal to introduce a crossing rule for steamships.

The French proposal was accepted in Britain without any discussion. There was no empirical need for a crossing rule; the rule was simply introduced to remedy a mischief which never existed!

It thus came about that the Order in Council of 1863 provided:-

Two ships under steam meeting.

Art. 13. If two ships under steam are meeting end on or nearly end on so as to involve risk of collision, the helm of both shall be put to port, so that each may pass on the port side of the other.

Two ships under steam crossing.

Art. 14. If two ships under steam are crossing so as to involve risk of collision, the ship which has the other on her own starboard side shall keep out of the way of the other.

Construction of Articles 12, 14, 15 and 17.

Art. 18. Where by any of the above rules one of two ships is to keep out of the way, the other shall keep her course, subject to the qualifications contained in the following article.

Proviso to save special cases.

Art. 19. In obeying and construing these rules, due regard shall be had to all dangers of navigation; and due regard shall also be had to any special circumstances which may exist in any particular case rendering a departure from the above rules necessary to avoid immediate danger.

Thus the concept of the stand-on ship (the so-called privileged ship) was born, but thereafter each so born would have a very uncertain life expectancy since she would be required to stand-on and rely on the other ship to take action to avoid the impending collision.   


In 1866 Commanders P. H. Colomb and H. W. Brent published their “Law of Port Helm – An Examination of its History and Dangerous Action with Suggestions for its Abolition – and an Appendix with Abstract of Cases, &c." This book, which contained a brilliant analysis of all the collisions casued by the port helm rule, was prompted by the failure of the nautical profession (including the Admiralty Court) to grasp the import of the 1863 Order in Council. The dangers identified in the book resulted in the Order in Council of 1868 which carefully defined the words "end on or nearly end on" to mean only the situation where each ship could see the masts of the other in a line or nearly in a line and where, by night, each ship could see both the coloured side lights of the other.


Order in Council Respecting the Application of Articles 11 and 13 of July, 1868.




Parliamentary Paper No. 114 of 1868-69 [Microfiche 75.475]

These papers commence with a letter dated 13th March, 1868, from the Dublin Surveryor to the Board of Trade, J. M’Farlane Gray, who was concerned about the inadequate screening of ship’s side lights which had been surveyed in other ports and could be seen across the bows. This led to instructions from the Board of Trade that the inboard screens, 3 feet in length, should be placed in line with the inner edge of the lamp wick rather than the lamp casing. Chocks on the forward edge of the screens were recommended to achieve this. The practical effect of this instruction was that both the red and green side lights could be seen together ahead of the ship in a sector of 3o.



Order in Council of 30th Janaury 1893.

Provided that light from side lights should cross a line projected from the keel at an angle of 4o at a reasonable distance ahead of the ship. This provision was to implement the Washinton Conference resolution that side lights would be seen “not more than ˝ a point across each bow”. The practical effect of this Order was that both the red and green light could be seen together ahead of the ship in a sector of 8o.


Parliamentary Paper No. [Microfiche ]



Dept. Cttee. On Screening of Ship’s Side-Lights 1895

[Microfiche 101.342-346]

This Committee considered the dangers created by the Washington Conference resolution and the Order in Council relating to the degree to which side lights would be seen across each bow. The Committee considered that too fine an angle would bring ships passing green-to-green or red-to-red into close proximity while too broad an angle would induce ships otherwise passing clear to cross each others bows. They concluded that the practice established in 1868 should be followed and calculated that this would provide a sector ahead, where both lights could be seen, of 3o.