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Pilot flag: United Kingdom

Last modified: 2019-05-15 by rob raeside
Keywords: united kingdom | pilot flag |
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Border = one-third of union height (1-3-1)

[Pilot Jack] image by Martin Grieve

Border = one-fifth of union height (1-5-1)

[Pilot Jack] image by Martin Grieve

Overall dimension 1:2

[Pilot Jack] image by Clay Moss, 13 November 2014

See also:

Pilot flag

[Pilot Jack] image by Miles Li, 15 September 2015

The following quote is from a "Mariners Mirror" article on British 19th century pilotage. The context is a description of the pilot's routine when boarding a ship to be piloted:

"Having reached the vessel's bridge, he had to raise a specific flag (measuring 1.80 by 1.20m, with two red and white stripes, either horizontal, for a first class pilot, or vertical, for a second class pilot) to indicate his presence on board the ship. This signal was meant to prevent any attempt to board by another pilot's cutter. Any infringement to that rule was severely punished, the infringing pilot having to refund the expenses of his colleague and being suspended for two days."

Source: Maritime Pilotage Acts of the Nineteenth Century, by Tri Tran, Mariners Mirror Vol. 89/1, February 2003, p. 44.

I believe that the USN currently uses the international flag "H" to mean "I have a pilot onboard" (among other things -- I recall hoisting it to indicate that the ship was conducting helicopter operations). Might there be a connection between the "H" (which is red and white) and the flags described in the MM article?
Peter Ansoff, 26 February 2003

I work in the UK Pilot boat industry. Our operations manager has uncovered some part of the Merchant Shipping Regs/IMO Regs that have changed the flag shown on a Pilot boat to that of the “H” red white side by side configuration. Which we now fly on our pilot boats out of Ramsgate and Sheerness. You state that it is “White over Red”, which was correct years ago, it has now changed, he says.
Mick Heywood, 20 October 2011

In 1934 the International Code Signal H replaced the white over red flag.
David Prothero, 20 October 2011


The civil jack (Pilot jack)

There is a different jack for civil vessels. This is an elongated Union Flag with a wide white border around it.
Graham Bartram
, 1 June 1999

The Pilot Jack (the white-bordered Union Jack) ceased to be a pilot signal in 1970. It is only used as the civil jack (also named merchant jack, but recreational boats may also use it). It is not very often used.
David Prothero, 31 July 2001, Jose C. Alegria, 2 August 2001

Can this flag be used on inland waterways like the River Thames? It is debatable as to whether the Merchant Shipping Act actually applies to inland waterways, however whether it does or not, the River Thames is a tidal river and as such should not (in my opinion) be so classed. It follows therefore, that Part 1.4(1)(a)(ii) of the Merchant Shipping Act (1995) comes into force and this specifically permits the use of "the Union Flag (commonly called the Union Jack) with a white border" as being one of the "distinctive colours" permitted to merchant vessels. The use of these "distinctive national colours" is nowhere forbidden in law in either inland or coastal waterways.
Christopher Southworth, 11 June 2004

The flag was introduced in 1823, and (whilst established in law from 1854 onwards) is no longer used for its original purpose and (from a date unknown but probably 19th Century) also assumed the role of a civil jack.
Christopher Southworth, 24 April 2011

See also:

Photograph of example of flag from National Maritime Museum in Greenwich (London): https://collections.rmg.co.uk/collections/objects/2290.html 
Peter Hans van den Muijzenberg, 13 April 2019

Development of the Pilot Jack

In the latter part of the 18th century the Royal Navy adopted, as the signal for a pilot, a Union Jack flown at the topmast head of a vessel with one mast, or at the fore topmast head of a vessel with more than one mast. I don't know if the selection of the Union Jack for this signal was deliberate or by chance.

British merchant ships, for whom pilotage was compulsory in Britain, followed the example of the Navy and adopted the same signal. It is surprising that this was allowed as, since 1634, it had been an offence for a merchant ship to fly the Union Jack . The Admiralty eventually took action to rectify this after Captain Frederick Marryat published the "Code of Signals for the Merchant Service" in 1817, and included the Union Jack as one of the set of signal flags. A warrant was issued on 15 November 1822 repeating that it was an offence for a merchant ship to fly the Union Jack, but temporarily authorising its use as a signal flag until 1 January 1824.

The Ship Owners of London opposed this and asked the Admiralty to end restrictions on the use of the Union Jack. It was a necessary part of Marryat's Code, which was about to be adopted by the French and Americans. The Admiralty replied that the use of the Union Jack as the signal for a pilot had been admitted, and the indulgence had led to its indiscriminate use. They were prepared to allow its continued use as a pilot signal for British ships, but felt it would be highly inconvenient if the Union Jack were to become part of a general code, particularly if the code were to be introduced into the French and American Navies. Their Lordships could see no reason why a different flag should not be substituted for the Union Jack.

The Ship Owners asked Captain Marryat to resolve the problem. He thought that the best plan was to take advantage of the fact that all British ships, whether men- of-war or merchant vessels, carried the Red Ensign, which had the Union Jack in one corner. He thought that if a Red Ensign was trimmed to leave just the Union with a red edge at the bottom and fly, the alteration would not be great enough to cause confusion, but would be sufficient to satisfy Their Lordships. It did not. It was pointed out that the suggestion did not limit the size of the margin, which might be so small as to be indistinguishable, and it was suggested that a flag of yellow and blue, or any other distinct colours, could replace the Union Jack. The Ship Owners proposed a Union Jack with a six inch red border on all sides. They thought this would be cheaper than introducing a new flag, as every ship already had a Union Jack. They also suggested that in the proposed Regulations relating to Pilotage the same flag should be specified as the signal for a pilot. Their Lordships agreed to this, but the border was to be white instead of red, and the size of the border was to be a proportion of the size of the flag.

The new flag was warranted on 8 July 1823, the details published in the London Gazette on the 9th, to be effective 1 January 1824. The change was included in the fourth edition of Marryat's Code published in 1826. The same white-bordered Union Jack was adopted by the Royal Navy as 'the Pilot Signal in all parts of the world' on 5 December 1826.
[Based on Memorandum on Merchant Ensigns and Jacks, 1674 to 1879.
Copies in PRO docs ADM 116/3566 and BT 103/308.
Article "The British Merchant Jack" by Cdr. Hilary P. Mead, R.N. in Mariner's Mirror Volume 21, pages 395-410, October 1935.]
David Prothero
, 6 September 2003

The white-over-red Pilot flag was first created by a British statute in 1808 (during the reign of George III). The 1808 Act provided that the pilot flag: (1) was to be carried in boats carrying the pilot, and then (2) in the ship in which the pilot was "carried off" to perform his services. In later years, these provisions were incorporated into the Merchant Shipping Act, and later into the successive Pilotage Acts. Since 1808, this white-over-red flag has thus been the Pilot Distinguishing Flag for Britain, and due to accession, for many Commonwealth nations as well. Many European nations copied the British practice, too, because it was widely understood. The Pilot Distinguishing Flag has been part of British law since 1808. No exceptions. (The flags used by ships to summon pilots have changed, however.) And in a fair number of nations, the simple white-over-red is the "Pilot Flag" also.

The International Code of Signals (to which Britain subscribes) provides that code flag "H" means "I am carrying a pilot" --but this provision speaks to ships under pilotage, not really to pilot boats offering their services and certainly not to pilothouses where the pilots await their jobs. The International Code Flag "H" --which is divided vertically white/red -- first appeared in Marryat's Code of 1817, and was later incorporated into the successive International Signal Codes. The use of this red-and-white "H" flag to convey a pilot-related message clearly stems from the practice started in 1808. Also, under the COLREGS, the lights displayed by a pilot boat at night are white over red; "White over red; pilot ahead!"

Britain's 1808 law did not apply to the USA, of course, and the white-over-red flag never caught on in the USA. In many US ports, the code flag "P" (Blue Peter) was used to mark pilot boats in the 19th century. This provision is still part of the law in Louisiana to this day (and was part of some states' laws for many years). The pilot boats of Houston, Texas, still carry the "P" flag in rigid form. The use of the "P" flag is at variance with the meaning assigned in the International Code, yet it is very firmly entrenched in local custom. "P is for pilot." Many Latin American nations followed the US custom, and used "P" (or at least a blue-and-white flag of some sort). Some US and Latin American pilot boats are painted blue. A few nations created unique pilot boat flags that follow neither the UK nor US traditions. This said, a few US pilots are now using the International "H" flag as a pilot boat flag (instead of "P"), under a broader interpretation of, "I am carrying a pilot".
James T. Liston, 16 March 2003

I have found no reference to the Union Jack with a white border before its introduction in 1823 as a signal for calling a pilot in the 'Code of Signals for the Merchant Service' of Captain Frederick Marryat which went through 10 Editions before being replaced by 'The Commercial Code of Signals of the use of All Nations' in 1857 (which was itself changed to 'The International Code' about 1880). If it had been introduced for any other purpose, I am sure we would have heard about it. The Union Jack was certainly used by the Royal Navy for signaling (as was the Ensign) prior to the introduction of an organized flag code, but always without defacement of any sort. The merchant marine are known to have flown a Union Jack - as a Jack - upon occasion, but this was strictly illegal and had been so since 1634.
Christopher Southworth, 4 September 2003

See also:

Anchor Ball and Pilot Jack

As the pilot jack today can only be used in harbour or at anchor, when used at anchor does it or can it act as a substitute for an anchor ball?
David Ward, 3 September 2003

The anchor ball is an option, not a requirement, and therefore the use of a jack as a substitute does not arise. The 1951 Seamanship Manual made the point that a warship did not normally hoist a black ball when at anchor, but the fact that she was at anchor (or made fast to the shore or a buoy) might be indicated by her jack flying from the jack staff.
David Prothero, 3 September 2003


Examination Vessels

[Examination vessels] image by Miles Li, 15 September 2015

Source: Campbell and Evans (1965)
See also: Canadian equivalent