X.1 Book Cover

Submarine cruisers have a great capacity to stir the imagination.

A powerfully armed vessel that can rise to the surface in a deadly ambush, sink an enemy vessel in a hail of shells, then simply slide away back into the depths.

Traditionally, the cruiser type of vessel is both the protector and the predator of mercantile sea routes worldwide.  But a lone raider far from base was always vulnerable to falling in with a faster or more powerful opponent.  The Great War gives us the examples of Königsberg and Emden, and the Second World War was to produce many others – including the fatal first and last cruise of the Bismarck.

Therefore the cruiser submarine, with her ability to hide from a hunter by simply submerging, seemed to many to be the ideal type of ocean raider.

The Royal Navy’s sole example of a cruiser submarine, the X.1, has long been dismissed as a failure, and a colossal white elephant.  She was the only major British warship designed after the First World War which was withdrawn from service before the outbreak of the Second.

Her heavy gun armament had great potential in a surface action role, defeating convoy escorts, leaving merchant ships or troop transports at her mercy.

Her advanced propulsion machinery fell far short of her designers’ ambitions, but every writer who mentions X.1 completely misses the most important aspect of this monster vessel: her docile underwater handling.  Designed to prove once and for all that a huge submarine vessel could be dived with safety, X.1 bridges the gap between the dangerous monster British submarines of the Great War, and the large Royal Navy submarines which followed her, right up to the present day nuclear boats.

Sadly, her concept failed to address the political context of the age into which she was launched.

The “X” in her pennant number stands for “experimental”, but it also brings an air of “mystery”, and the story of X.1 is no stranger to mystery and subterfuge.

This volume aims to lay to rest once and for all the deliberate, and innocent, misinformation spread about X.1, and tell the true story of the Royal Navy’s extraordinary secret weapon and her crew.

Available now from Seaforth Publishers or your favourite bookstore

I am preparing an e-book to contain all the David Hill collection of illustrations showing interior views of X.1, which David drew from the general arrangement plans but also the complete book of X.1’s fittings. Watch this space…



U Cruiser painting by Willy Stower

A colour version of the Willy Stower painting on Page 16

Colour cover mag

The cover of the Magazine shown on page 84.


X.1 Magazine page 12 The Man Who Wished

The unfortunate out-of-work sailor who missed out on sailing on X.1, but also missed out on being included in my book in the Magazine section, beginning on Page 84…..


X.1 Salmon Colour Postcard

The coloured Salmon postcard of X.1 shown on page 104.



Narwhal at Pearl

The original photo of Narwhal at Pearl Harbour from which the small view on Page 110 is taken.

On magnifying the photo to clean up the dust specks ready for printing, I came across a tiny Mitsubishi Zero flying from right to left and obviously the subject of attention of the sailors in the foreground! The position of the Zero is indicated by the white oval I have added.


The Submarine Surcouf

The view of Surcouf on Page 113 showing her dark Prussian Blue finish. The model of her in the Musée de la Marine in Paris is incorrectly painted dark green. The Prussian Blue is the correct shade.


Surcouf Stamps

The stamps of Surcouf on Page 118. The 500 franc stamp shows her in her original configuration, unlike the later stamp which correctly depicts Surcouf as in 1941.


New Photo 194 Box art of IJNS I-400 at periscope depth

The box artwork for Aoshima’s 1/700 scale I-400 shows an unusual view of this monster submarine cruising at periscope depth, not using her schnorkel.


TORPEDO MODELS of Japan produce from time to time a very smart 1/350 scale solid resin model of X.1, under their Reference WF-17.

As well as adding handrails and the ladder in front of ‘A’ Turret, there are certain changes you need to make to correct minor inaccuracies in the kit.


X.1 forward hydroplanes plan view

The forward “biplane” hydroplanes are incorrectly shaped. The drawing above shows the correct shapes of the upper, larger, and lower, smaller, forward hydroplanes.  Note that when the upper set are retracted they still protrude slightly from the hull.  Below is a drawing of the forward hydroplanes seen in section.


X.1 forward hydroplanes sectional view

The rear hydroplanes are also incorrectly shaped.  The plan view below shows the correct profile, and also shows the round hole in the centre of the small triangular pieces “00”, which are in fact the hydroplane guards. Instead of being triangular they should be the shape shown.


X.1 rear hydroplanes & guard plan view

In reality, ‘A’ Turret and ‘Y’ Turret were in fact identical.  In the kit two different turrets are provided.  ‘The triangular section molded on the bottom rear of Part “3” is in fact part of the superstructure.  If you intend to allow the turrets to revolve, you should file off this projection until both turret bases are identical, then glue a triangular wedge of plastic to the hull top.

Kit Part “3” (‘A’ Turret) also has a vertical bar molded onto its front.  In fact this was the removable chimney for one of the galley stoves, brought into use when running on the surface. If you wish to depict this chimney you should file off the molding and replace it with a longer pipe, complete with a “H” attachment on top.  In this configuration obviously the forward turret cannot revolve!  Otherwise, simply file off the projection.

Asdic dome cover

There is one more change, purely for the most fastidious of modellers.  The kit depicts the Asdic dome in the raised position, and this is most appropriate when diving, i.e. with the chimney in front of ‘A’ Turret removed, the turrets secured pointing forward, and the forward hydroplanes deployed.

When on the surface, the fragile Asdic dome and its crystal transponder, even when retracted,  were vulnerable to blast effects from the muzzles of the guns of ‘A’ Turret overhead, so a protective cap was arranged to hinge up into position as the dome retracted.  You can represent this by a disc of plastic card superglued on top of the Asdic housing, after you have filed off the dome itself.

X.1 sported various colour schemes over the years, and these are fully discussed in the relevant section of my book.


Test Model definitive

The photo of X.1’s 1/20 scale operational model at Hornsea Island 1924, as printed on page 29. The personnel in the photo are

Standing at left: ERA Harris; standing at right: ERA Smith

Seated, left to right: Shipwright Bentley, ERA Donaldson, Commander J F Hutchings DSO, EA Rowlands, EA Wadey.



Here is another view of the 1/20 scale model, from the photo collection of Vice Admiral Sir Cecil Ponsonby Talbot, courtesy of Michael W. Pocock. His excellent site is at www.maritimequest.com



Here are Commander Hutchings and his team testing the model (courtesy of Michael W. Pocock)



Off she goes in search of a miniature convoy (photo courtesy of Michael W. Pocock)



X.1 in her natural element (photo courtesy of Michael W. Pocock)



Surfacing: In this view an enemy would not suspect they are faced with a submarine cruiser

(Photo courtesy of Michael W. Pocock)



Now she shows her teeth. (Photo courtesy of Michael W. Pocock)



To show that submarine cruisers could use their torpedo armament when needed, here is an advertisement for the Electric Boat Company, based on the famous periscope shot of Yamakaze sinking, after having been torpedoed by USS Nautilus on 25th June 1942.


5.25 Turrets under construction 2

The later twin DP turrets with long-barrelled 5.25in guns under construction for the KGVs and Didos at the Vickers factory.


Readers have kindly pointed out two minor glitches, which I here correct:

1.  On Page 14, I describe the wreck of M.1 being discovered off Portland in 1999. In fact the wreck of M.1 lies in much deeper water south of Bolt Tail in Devon, where she was discovered by Innes McCartney in 1999.

2.  On Page 187 in Note 1 to Chapter 9, I mentioned the ‘B-1’ stealth bomber, when of course I should have written ‘B-2’.


What readers think of my book on X.1

“Even now I find it a bit difficult to believe that the X.1 actually existed, but I’ve looked through the book several times and taken in the stunning archive photography and imagery. The author’s superior descriptions have made it all clear to me. The boat was real.

The artwork and scale drawings are fantastic and…the photos are really terrific, you get the full treatment with this book, and my initial concern that it might not be one of those volumes you’d be able to pick up and leaf through as and when suits was misplaced – it is. The book is not simply broken down into a technical history and service life of the X.1. Rather it is a really impressive – I want to say ramble – but that would be a disservice, so I will say cruise (much more appropriate) through the conceptualisation, development and then the trials and tribulations of this most singular of submarines.

Mr Branfill-Cook tells a fascinating story in  a way that makes it easy for the layman to follow and you can really get into it. The book is user friendly because, as said, it is lush and I don’t mean that in a shallow way; it is just done so well. Reviewer: Mark Barnes, War History Online.


“Life aboard ship, trials, excursions and exercises…. This is the section of the book that explores the intrigue and human element of X.1. Not all of the stories are dramatic, and it is easy and enjoyable to be drawn into the stories of everyday life for the crew…. The concluding Chapter is Branfill-Cook’s interpretation and opinion regarding the life and eventual perceived failure of X.1. The author successfully brings together the prior eleven chapters to support his arguments. The reasons for the unfulfilled potential of X.1 and its tragic end are explored and possible explanations discussed….

Although a reader might be overwhelmed by the technical jargon of this book, any avid student of submarine or Royal Navy history would find themselves in familiar territory….. The singular focus of the book allows for a range of subjects, from exhaustive documentation of technical details to personal stories of life aboard X.1. Branfill-Cook successfully uses this focus to put to rest some of the myths surrounding X.1 and replace them with the true tale of “the Royal Navy’s mystery submarine”.” Reviewer: Julie A. Powell, East Carolina University, for the Nautical Research Guild.


“What’s in the book? Schematics, blueprints, art impressions of the inside of the submarine, plenty of photos, historical context, technical details, log entries of the submarine, comparisons with other submarines of the time, historical lessons.

First impression, One of the best books I have come across regarding the topic of cruiser submarines.

Print quality? Superb.

Layout? Very well composed with schematic drawings, charts, photos, all in good number accompanying well-elaborated chapters.

Drawings? A very good number of blueprints of all parts of the submarine and related to the topic plus a few most interesting art impressions of the interior.

Photos? A wide selection of photos, some unknown to me, and of very good quality in printing and clear enough to give some use to modellers.

Also includes? Includes brief information and history regarding other submarine cruisers from WWI to WWII and logbook entries taken from Admiralty Records.

Anything missing? Taking into account the obscurity of the topic the book covers it quite well. Better work would have been difficult….

Value for money? Worth every penny/cent you spend on it. As a matter of fact it’s not a subject widely covered in books so you can’t get many other options.

Modelling use? Most useful reference for submarine builders….

Any other business? ….Probably one of the best submarine books I have bought in the last decade.”

Reviewer: Filipe Ramires, finewaterline IPMS.


“The book is richly illustrated with drawings and rare photographs, many never previously published.

X.1: The Royal Navy’s Mystery Submarine will be of great interest to readers who are submariners, naval enthusiasts, or historians of military technology. It describes a lost era before advances in radar and sonar made the life of the submariner more precarious; before the snorkel, acoustic quieting and ultimately, nuclear propulsion, turned submersible boats into true submarines. It offers a unique glimpse into an unhappy period of the Royal Navy’s epic history.” Reviewer: Mike Markowitz, Defense Media Network


“… of the books published on warships and naval operations during the Twentieth Century, most new books are taking another look at a subject covered many times before by other authors. Then occasionally, a book is published that covers an important warship that has somehow managed to escape serious coverage before. This book is one of those rare new books.

… experimental submarines…have received much coverage from publishers, almost beyond that merited by their place in naval history……The one submarine to escape attention has been the British X.1 and this new book goes a long way to correcting this omission.

The author has written an engaging account of the development and operation of the X.1 and also placed it in historical context……….  The level of information is excellent and based on solid research.” Review posted in Nighthawk News.


“5 Stars. The man and the moment meet in this superb, detail-rich survey of giant pre-nuclear submarines. The X.1’s history, description and analysis are encyclopedic, it stands alone as an exemplar of excellent military technical writing. By putting the X.1 in its historical context with other similar “boats”, the book becomes an important historical work about a world almost at war. The wealth of photographs, David Hill drawings, and schematics are peerless. This work is the last word in this little known area of significant technological development between the wars.” Reviewer: Amazon customer Michael A. Mendelson.


“5 Stars. The book begins with the history surrounding the emergence of the first really big submarines, and the perception that existed in some minds at the end of WWI, that future navies would include underwater cruisers, aircraft carriers and possibly more…. It is from the inclusion of this peripheral information that we come to realise the depth of research and information included on every aspect of the story of HMS X.1.

[Chapter] 10. An Unlucky Fall …was the incident in which the boat capsized in dry dock and, ordinarily, might have brought the book to its conclusion. Instead of this, however, we find two more exhaustive chapters…… Chapter 12 allows the author to place his own thoughts into perspective by dwelling on ‘what might have been’ amongst other topics.

Lavishly illustrated with plenty of line drawings and plans covering every element of the different craft under discussion, artwork and plenty of relevant historic photos, the work concludes with three Appendices, Notes, Bibliography and Index, and is as complete as one might hope to find.

Altogether a definitive account of a single vessel viewed from every conceivable angle. Reviewer: Amazon customer Ned Middleton. 


“5 Stars. This book is a well-organized and fascinating account of a very little-known ship……This book is not for the casual reader of naval history but rather for the enthusiasts who want to fill the holes in their knowledge left by other narratives, that are too general to include the “one-offs” that pushed the then-current thinking outside of the parameters to which traditional …naval [policy makers] wanted to adhere.” Reviewer: Amazon customer G. Dorn.



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