No Room for Mistakes

British and Allied Submarine Warfare, 1939–1940

Geirr H Haarr

• Publisher: Seaforth Publishing
• Year: 2020
• Print ISBN: 9781848322066
• eBook ISBN: 9781473875302
• Subtopic: British History

A highly readable and detailed account of British and Allied submarine warfare in north European waters at the beginning of World War II.

The early chapters describe prewar submarine development, including technical advances and limitations, weapons, tactical use and life onboard, and examine the men who crewed them and explore their understanding of the warfare that they would become involved in.

The core of the book is an account of the events as they unfolded in "home waters" from the outset of war to the end of 1940, by which time the majority of the Allied submarines were operating in the Mediterranean. It is a story of success, triumph, failure and tragedy, and it tells of the tremendous courage and endurance shown by a small group of men learning how to fight a new kind of war in claustrophobic, sub-sea vessels with limited information about the enemy, or what they would meet off the alien coasts to which they were heading. Extensive primary sources are used to document the many aspects of this war, some of which remain controversial to this day. 

Max Horton, Vice Admiral Submarines 1940, said: "There is no room for mistakes in submarines. You are either alive or dead." This book makes plain how right he was.

"My favorite aspect of No Room for Mistakes is Haarr's extensive use of primary sources, including diaries, logs, journals, and photographs. These materials help make the historical account of this period much more poignant and remind the reader of the high human cost of war at sea." — Naval War College Review

— 1 —

The Admiralty Regrets

‘…has failed to surface’

THETIS, THE FIRST OF the new T-class submarines to be built at Cammell Laird’s yard in Birkenhead, slid down the slipway into the river Mersey on 29 June 1938. Within months, officers and ratings assigned to her crew arrived at Birkenhead to familiarise themselves with their new boat and see her through the fitting-out and work-up period. Thetis’s commander, Lieutenant Commander Guy ‘Sam’ Bolus was among the first, as was Lieutenant Frederick Woods, the torpedo officer. He arrived in October 1938 to oversee the torpedo room assembly, including the tubes and their internal and external fittings.

The early trim and torpedo-firing tests were conducted in Cammell Laird’s Wet Basin in March 1939. A number of minor items were logged for attention, including pipes and indicators that were found to be missing or had not been properly connected. Lieutenant Commander Bolus took Thetis to sea for the first time in late April. Prior to leaving the yard, Thetis had been declared seaworthy by Bolus, Principal Ship Overseer Lieutenant Albert Hill and some officials from Cammell Laird. Even so, the trial was a complete failure, embarrassing to the naval personnel as well as the shipbuilders. Firstly, when orders were given for port rudder, Thetis promptly swung to starboard: the steering mechanisms had been incorrectly fitted. Secondly, the forward hydroplanes jammed when tested. Bolus decided enough was enough and turned back. The fact that such faults could have escaped the yard’s own quality control as well as the navy overseers seems to have been taken rather lightly.

Thetis in the wet-basin at Cammell Laird, testing trim and basic operations. (Author’s Collection)

While the repairs to the steering gear and rudder were effectuated, the insides of the six forward torpedo tubes were coated with bitumastic paint and enamel to prevent corrosion and ensure the torpedoes would run smoothly. This highly specialised work, which included liquidising the solution with a blow torch, had been sub-contracted to the Wailes Dove Bitumastic company. Upon completion, the job was supposedly inspected and approved by an assistant Admiralty overseer who, it seems, had no previous experience with this kind of work. How well this inspection was performed would later become an issue of contention among those involved and is still disputed today.¹

Eventually, Thetis was declared ready and left Birkenhead for a second attempt at passing her diving trials on the morning of 1 June 1939. Unlike the first time, when the trials were to have been performed in the sheltered Gare Loch off the Clyde, Bolus this time intended to go no further than Liverpool Bay to save time. Thetis had not been commissioned and was technically still the property of Cammell Laird. The purpose of the sea trials was to verify that the ship had been built according to contract so that invoices from the yard could be honoured. According to Admiralty manuals, all trials ‘shall be conducted at the risk and at the expense of the Contractors. […] The diving, trimming and submergence trials shall be carried out by Naval Officers and crew. The contractors shall work the main and auxiliary machinery etc., and provide a pilot with attendant vessel.’ The shipbuilders were not trained to work together as a team and the navy provided the crew to operate the submarine during the tests. Lieutenant Commander Bolus would be the connection between the two sets of men and no one had any doubt that he would hold sole command at sea. The whole trip was supposed to last for thirteen hours, of which three would be submerged.²

In addition to Thetis’s complement of fifty-one, a large number of Cammell Laird personnel, overseers and observers had embarked, making a total of 103 men on board. The extras were Henry Oram, Captain(S) of the 5th Submarine Flotilla at Gosport, nine other naval officers, six civilian Admiralty overseers, thirty-three employees of Cammell Laird and Vickers-Armstrongs, two employees of a catering firm and a pilot. The naval board of inquiry later concluded that at least a dozen of these should have disembarked before the test-dive commenced.³ To escort Thetis and stand by on the surface during the trials, Cammell Laird’s tug Grebe Cock under Master Alfred Godfrey had been chartered. Also on board the tug were Lieutenant Richard Coltart and telegraphist Victor Crosby. It was intended that personnel not strictly needed on board Thetis should transfer to Grebe Cock before the dive. At 13:30, though, some fifteen miles off Great Ormes Head, Grebe Cock was hailed and informed that nobody would disembark the submarine and that the dive was about to commence. Ten minutes later a signal was sent from Thetis to the 5th Submarine Flotilla operations centre at Fort Blockhouse, Gosport, with a copy to the Admiralty and C-in-C Portsmouth, informing them that the submarine was ready to begin its dive and would dive for up to three hours. Captain Oram later wrote:

Picture the Control Room crammed with people. Under normal conditions, the captain would have been surrounded by his First Lieutenant, Navigating Officer, two hydroplane operators, helmsman, asdic operator and his mate, the Electrical Artificer, the Outside ERA and his mate, the Control Room messenger and the signalman. That adds up to ‘a ton of men’ according to the old submarine saying. In Thetis’ Control Room that day, we were nearly a ton-and-a-half, including the two other submarine captains, the Admiralty Constructor, Mr. Bailey, and myself. Conditions were undeniably cramped […]. Bolus was standing at the periscope and I was somewhere near him just watching what was happening. […] We made ourselves as inconspicuous as possible. Then came the command: ‘Open up for diving’.⁴

At first, there was a rush of air from the submarine, clearly heard on board Grebe Cock, as Bolus ordered the main vents to be opened. Once the tanks had been filled, Thetis should have been at neutral buoyancy and able to dive using her hydroplanes, slowly and deliberately, to maintain control. To the surprise of those aboard the tug, though, Thetis did not submerge as expected, until, just before 15:00, she suddenly disappeared beneath the surface.⁵

When, at 14:00, Lieutenant Commander Bolus gave the order to take Thetis down, she was too light and unable to dive, even with the use of increased speed and hydroplanes, as well as additional water being taken into the auxiliary tanks. A check of all the tanks was instigated to verify that the amount of water on board corresponded with the ‘trim chit’.⁶ This included an inspection of whether the internal forward torpedo tubes (numbers five and six) had been filled with water, as they were supposed to have been before leaving the yard, effecting ballast in the absence of torpedoes.

On the inner rear door of each torpedo tube, a small-bore test-cock could be opened, allowing liquid to spill out in a controlled manner if the tube contained water. No water coming out of the test-cock would indicate it was empty, or nearly so, and therefore that the bow cap was closed. On this morning, with Thetis still on the surface, the torpedo officer Lieutenant Woods opened the test-cocks on tubes five and six to verify they contained water. Number six tube produced a small amount of water, indicating it was at least half full. From number five test cock, there was nothing – neither air nor water. Woods concluded that number six tube had some water in it and number five was empty or nearly so. He made his way to the control room and reported his findings to First Lieutenant Harold Chapman, asking if they were not meant to be full. To his surprise, he got conflicting answers. Chapman confirmed they should be full, while the supervisor from Cammell Laird, Arthur Robinson, said no, and that this had been changed from that on the trim chit and they were now empty. Lieutenant Chapman sent him back to check once more. Convinced that number five tube was empty, Woods this time checked only number six tube and, getting the same result, reported to the control room that this was half full.⁷

Thetis leaving Birkenhead in the morning of 1 June 1939. (Wirral)

Unknown to all on board, during the painting and subsequent enamelling of the torpedo tubes, the inspection hole leading to number five test cock had been blocked, creating a stopper that now prevented water from the torpedo tube dripping out, thus unable to reveal the true status of the tube. This had not been discovered by the naval overseer Edward Grundy or the commissioned engineer Roy Glenn, neither of whom had examined the interior of the doors meticulously.

To verify that the inspection tubes were open and free of debris, a 10-centimetre (4-inch) brass pin, known as a rimer, was provided in a housing at each door, to clear any obstructions. Woods did not use the rimers, either the first time he checked the tubes or the second time, after coming back from the control room. He later stated that he believed the employees of Cammell Laird should have checked that the holes were clear in a new submarine and that he had not even noticed that there was a rimer fitted to the test cock. Neither did Woods check the inboard drain valves, which were meant to empty a tube flooded after firing a torpedo before loading a new one. Had he done so, this would unequivocally have revealed whether there was water in the tube. The report from the naval inquiry later concluded that the general safety instructions, as well as Woods’s training on this point, had been inadequate.⁸

Having reported again the status of the torpedo tubes, as he believed them to be, Woods asked Chapman if he might be requested to fill the tubes. Receiving a confirmation to this, he started to prepare the necessary procedures to do so if requested. Woods then started to inspect the tubes to see if they were dry by opening the inner rear doors. Why this was necessary at this stage was never fully explained and it is incomprehensible that he would do so without the consent of Bolus or Chapman. If the two tubes had been flooded for ballast as intended, the water would have run into the bilges when the doors were opened, upsetting the trim even further. At the tribunal, Woods said that he:

wished to inform the First Lieutenant of the state of the tubes and to see if they were dry myself [and] that the bow caps were not leaking. […] I had information from a Cammell Laird official that the tube was not full. That, coupled of course with the use of the test cock, wiped out in my mind any idea that it was full.⁹

As part of the door-opening procedure, Woods ordered power to be put through to the telemotor bow-cap operating panel. Provided the bow-cap operating levers were in the ‘shut’ position, this should have resulted in all caps being shut, if they were not already so. It could not be ascertained later with absolute certainty that switching the power to the forward section had been fully effectuated in time. The operating levers were mounted on a small panel, outboard of the tubes. The levers of tubes one, three and five were on the starboard bulkhead, the other three on the port. In addition to ‘open’ and ‘shut’ the levers had a central ‘neutral’ position. It appears from several statements that when Thetis left port that morning the operating levers were at ‘neutral’ rather than ‘shut’ position, contrary to practice. If the lever was taken from ‘open’ directly to ‘neutral’ without being taken all the way over to the ‘shut’ position first, this may explain why number five tube was open. Woods insisted the operating levers were all reported in the ‘shut’ position, but admitted he had not checked himself that they were.

Instead, he maintained, he checked the mechanical bow-cap indicators to ascertain they were in the ‘shut’ position. These indicators were badly positioned and had a confused layout on the forward bulkhead, between the two vertical columns of rear doors. From top to bottom, the indicators were arranged in pairs, one mirroring the other so that what was read on one indicator appeared opposite to the way it was read on the one below. They had to be inspected from close up and could not all be seen at the same time. Number two was on top, followed by number one, four, three and six with number five at the base. Woods later said: ‘I remember repeating in my mind, as I looked at each indicator, the words “shut”, “shut”, “shut”, looking at number five first, then progressing upwards. I was satisfied at the time that it did show me “shut”.’¹⁰

Leading Seaman Walter Hambrook was assisting Lieutenant Woods. They had worked together on board the Osiris, where the forward lay-out was similar, and the two men knew each other and the routine the...

Table of contents

• Cover
• Title Page
• Copyright
• Dedication
• Contents
• Acknowledgements
• Introduction
• Chapter 1: The Admiralty Regrets
• Chapter 2: The Thin Grey Line
• Chapter 3: The Submariners
• Chapter 4: ‘… the Violence of the Enemy’
• Chapter 5: ‘… the Dangers of the Sea’
• Chapter 6: A Slight Drizzle
• Chapter 7: The Polish Predicament
• Chapter 8: A Most Appalling Crash
• Chapter 9: Luck and Good Fortune
• Chapter 10: Something Less Than God
• Chapter 11: Negative Flag
• Chapter 12: First Blood
• Chapter 13: Action Taken
• Chapter 14: A Most Unpleasant Day
• Chapter 15: Freedom of Action
• Chapter 16: Out of the Fog
• Chapter 17: Le Grande Patrouille
• Chapter 18: Fear of Invasion
• Chapter 19: ‘We’ve ’it a Bleedin’ Mine’
• Chapter 20: Submarine Mining Operations
• Chapter 21: Black, Filthy Water
• Chapter 22: Deep-Sea Stalkers
• Chapter 23: Allied Submarines
• Chapter 24: A Summer of Grief
• Chapter 25: Cygnus’s Convoy
• Chapter 26: Loss of Shark
• Chapter 27: Brushes
• Chapter 28: Autumnsong
• Appendices
• Abbreviations
• Notes
• References