Most of us can differentiate between officers and ratings uniforms and most of us can pick out naval uniforms which are not British.

But, do you know why virtually every naval uniform and mercantile navy uniform irrespective of country, is basically dark or navy blue with

some white parts and some gold or yellow parts ?

Admiralty sources reveal that a King of ours [British] admired [or did he fancy] the way a certain lady dressed when out horse riding.

She evidently wore a navy blue tunic [long dress] - no jodhpurs or hard hats in those days -  draped down her legs [side saddle fashion]

with a white silk hat band adorning her blue felt hat, white gloves and white blouse.  However, knowing ladies of my social standing never mind

rich ladies, you can bet that she wore many different colours and many different outfits, but the King fancied her wearing these colours.

She, the Duchess of Bedford, was the wife of the First Lord of the Admiralty, one John Russell 4th Duke of Bedford, and the then King, King

George II decreed that his navy should also dress in these colours.  Thus all naval uniforms, colour but not necessarily style,  date from the mid

18th century and all copied Britain.

Now, they say history always repeats itself and there is some truth in that in the following story.

Lady Diana Spencer was born in 1710 daughter of Charles Spencer and Lady Anne Churchill daughter of the 1st Duke of Marlborough.   For much of her youth she lived with her maternal grandmother Sarah Churchill Duchess of Marlborough in Windsor.  The old Duchess wanted most of all a marriage for Lady Diana to none other than the Prince of Wales.  However the King, George II and the Prime Minister Robert Walpole turned down the match and instead, Lady Diana married, in 1731, John Russell 4th Duke of Bedford. As 'our' Lady Diana [Princess Diana] died very young when aged 36, so too did this Lady Diana, in 1735 when just 25 years of age.  The Duke of Bedford remarried in 1737 Lady Gertrude Leveson-Gower, and it is this lady who caught the eye of the King whilst out riding. 

Lady Gertrude [died in 1794], as the Duchess of Bedford is an important lady for other reasons in British history now firmly with 'our' Lady Diana [Princess Diana] in mind.! In generational terms she is the;

Great Great Great Great Grandmother of Winston Churchill
Great Great Great Great Great Great Grandmother of Princess Diana
Great Great Great Great Great Great Great Grandmother of Prince William

Just to give you a quick history lesson, the following dates will help.

King George II [born 1683, King from 1727 to death in 1760].

4th Duke of Bedford [born 1710, died 1771].

King George III [born 1738, King from 1760 until death in 1820].

Lord Horatio Nelson, Admiral [born 1758 died 1805] apart from first two years, lived the whole of his life under King George III.

During my researches I have found several authoritative definitions of the abbreviation DOB.  If we were to add the Duchess of Bedford, some of them were:

DOB - meaning Date of Birth
DOB - Duchess of Bedford
DOB - Died on Board {usually, when a person died on board, he was marked as DD = Discharged Dead, and if at sea, his body would be committed to the sea and if in harbour, taken ashore for burial. However, in very rare circumstances, if at sea and the body was not to be disposed of, i.e. it was not to be discharged [into the sea] it was retained and landed, recorded simply as Dying [or Died] on Board}.  Lord Nelson was one such case.
DOB - Duty on Board as opposed to 'Ashore on Duty'.
DOB - Disease on Board.  An expression used in the PRATIQUE International system of signalling the health of a ship and its company or manifest on arrival at a Port of Call.
DOB - Discharge of Bilges.
DOB - Diesel Oil Bunkering -used in the early days to differentiate between diesel and FFO [Furnace Fuel Oil].

This detail, of the reason for naval uniform colours, is recorded in The Early Georgian Navy [Admiral Roger Prendergast] and also in BR1938 [dated 31st October 1951] Page 27, fourth paragraph last sentence.