Facts and Figures

Facts and Figures

The First World War at Sea is often poorly understood and its significance less realised when considered next to the more recognised image of the First World War - the Western Front. In fact the maritime element of the war was what made the war a truly global conflict, and some of the facts, figures and tales form it may surprise you. 

Below are some of the facts that have emerged from the research conducted by the Forgotten Wrecks project.

British Losses

How many ships did Britain lose during the First World War?

The Admiralty kept detailed records of the events at sea between 1914 and 1918, and in 1919 they published the basic details of every ship lost in the book British Vessels lost at Sea, 1914-1918 (HMSO).

However, this list doesn’t account for vessels lost to the normal hazards of the sea (such as the weather, collisions, groundings or other accidents), only those lost to ‘war causes’. Additionally, 1919 was still quite early and not every vessel could be firmly said to have been lost in the manner stated. Some believed to have been lost to maritime hazards would subsequently be found to have been lost to enemy action or to have been captured. All of this is relevant to the Forgotten Wrecks project as it means that ships like War Knight are not included in the book.

There is an online effort to update these figures (see British Vessels lost at Sea) but it is ongoing and not complete. The original publication therefore remains the most complete list of ‘war loss’ British vessels.

The publication lists the following totals of ship losses:

Warships: 254

Fishing Vessels: 675

Auxiliary Vessels: 815

Merchant Vessels: 2,479

Total: 4,223

Taking just the Merchant ships by year, it is easy to see when the most catastrophic period was. This was a consequence of the all-out effort by the German Navy to destroy the British Mercantile Marine.

British Merchant ship losses 1914: 64

British Merchant ship losses 1915: 278

British Merchant ship losses 1916: 396

British Merchant ship losses 1917: 1,197

British Merchant ship losses 1918: 544

Losses to U-boats

It’s a little recognised fact that U-boats of the Kaiserliche Marine (the Imperial German Navy) sank far more vessels in the First World War than U-boats of the Kriegsmarine did in the Second World War. Exact figures are difficult to come by, but a number of records put together after the war, and more recently, show the extent of the difference.

In The U-boat War 1914-1918, Edwyn Gray claims that “according to the most reliable statistics available, a world total of 5,708 ships were destroyed by the U-boats, representing the almost incredible total of 11,018,865 tons capacity.”

This figure has most likely come from the British statistics published after the war and in The U-boat Offensive 1914-19145, V.E. Tarrant includes quite detailed statistics on merchant ship losses to U-boats that match it quite closely. He also observes that research suggests the German totals tend to be more accurate and include losses to mines laid by U-boats. The figures provided for 1917 may therefore be considerably higher than the British total.

Year German Figures British Figures
1914 3 (2950) 3 (2950)
1915 636 (1,191,704) 468 (1,176,829)
1916 1,309 (2,186,462) 1,125 (2,108,530)
1917 Unknown (6,149,070) 2,609 (6,026,128)
1918 1,305 (2,754,152) 1,077 (2,649,748)
Fishing Vessels: Already Included 614 (62,139)
Total 5862 (12,284,757) 5896 (12,026,324)
(Using British figure for 1917)
Business in Great Waters: The U-boat Wars 1916-1945 by John Terraine, includes the following totals in Appendix C: 12,850,814 tonnes of worldwide shipping sunk by U-boats between 1914-1918, of which approx 7,759,090 was British Merchant shipping. Sourced from CE Fayle, Seaborne Trade (1924). More recent research has been conducted by project volunteers Peter Crick and Richard Wyatt, who have checked the losses attributed to U-boats on the comprehensive website U-boat.net. These totals include attacks, damaged vessels, captures and sinkings caused by all forms (scuttling, deck gun, torpedoes and mines) and include U-boats of the German Navy and the Austro-Hungarian Navy. The losses also include warships, something that post war totals tended to ignore.

The totals came to:

7655 total attacks carried out by U-boats.

691 (2,742,917 tonnes) ships damaged.

115 ships captured and taken as prize

6849 ships sunk

So the post war statistics reach as high as 5,800 (mostly merchant) ships sunk by U-boats, whilst more modern research suggests that possibly 1,000 more ships of all types were lost to U-boats. By comparison, the most reliable statistics for the Second World War suggest that only approximately 3,500 attacks were made on ships by U-boats, resulting in approximately 3,100 ship losses. In Business in Great Waters: The U-boat Wars 1916-1945, John Terraine identifies 5,140 ship losses to all causes in the Second World War, substantially less than the total number just to U-boats in the First World War.
Fleet Sizes

If you read a book on the First World War at Sea, there’s a good chance that it will list the numbers of battleships that both the Royal Navy and the Kaiserliche Marine (the Imperial German Navy) had available to them at the outbreak of war. There’s also a good chance that if you read another book, it will give you a different set of figures. Why are there these variances in number and how have they come about?

The confusion in numbers seems to be a result of different admirals, historians and authors counting ships that had been launched whilst others counted ships commissioned into the fleet. It could be a whole year between a ship launching from the slips in a shipyard to it being fully armed and equipped and accepted into service, so the difference is important. Other errors seem to occur when deciding whether a ship is a battleship, Dreadnought battleship, pre-Dreadnought battleship or, in the case of the battlecruisers, the differences with armoured cruisers in the German Navy.

Both navies had been building large ships, which took the descriptive name of battleships, throughout the latter half of the 19th century. However, in 1906, HMS Dreadnought was launched and commissioned into the Royal Navy. Her design revolutionised capital ship design and her name was used to describe the subsequent rush of similarly designed warships – known as Dreadnought battleships. Generally speaking, battleships and Dreadnoughts amount to the same thing, but pre-Dreadnought big ships (anything launched before HMS Dreadnought) were still officially called battleships. Even though they were of a weaker design and were obsolete at the outbreak of the war, both navies had considerable numbers in their fleets. These included HMS Formidable (lost in the Channel on 1stJanuary 1915) and HMS Hood (scuttled as a blockship in Portland Harbour in 1914). Several German pre-Dreadnought battleships even saw service in the Second World War.

To aid the confusion, battlecruisers are often mixed in with battleships. To the eye they look identical, but sacrifice armour for speed, hence the different classification. Many authors and books will class them and Dreadnoughts together under one title (usually as battleships).

The actual number of ships that both the Royal Navy and the Kaiserliche Marine had available on 4th August 1914 is listed in the table below. As you might expect, some of the ships already launched and still undergoing trials in July 1914 were commissioned very quickly – this table would therefore look quite different at the end of August 1914.

These totals tally with Robert Massie’s research in his book Dreadnought. His only error is classing the armoured cruiser Blucher as a battlecruiser. In fairness, the German navy liked to call it a battlecruiser, but in fact it was an older vessel and not comparable with true battlecruisers.  


 In commission 

Launched (but not yet commissioned)

Under construction













Pre-Dreadnought Battleship




















Pre-Dreadnought Battleship




As can be seen, the Royal Navy had a significant advantage in capital ships, which were, at the outbreak of the war, still considered the basis of any fleet. Four years later, the Royal Navy and Mercantile Marine’s experience in the English Channel would demonstrate that the days of the big gun ship were numbered and that the submarine (and soon the aircraft) would be the dominant elements of a fleet.

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