HMS Mentor (1914)

HMS Mentor was a Hawthorn Leslie special M class destroyer that served with the 10th Flotilla at Harwich in 1915-17, fighting at the battle of Dogger Bank, then with the 6th Flotilla at Dover for the rest of the war, taking part in the Ostend raid.

The Mentor was laid down at Hawthorn on 9 July 1913, launched on 21 August 1914 and completed in January 1915. The Hawthorn Leslie specials had four boilers and four funnels, while the Admiralty types had three of each


At the battle of Dogger Bank of 25 January 1915 the Tenth Flotilla contained the Aurora, Meteor, Miranda, Milne, Mentor, Mastiff, Minos and Morris, organised into a single ‘M’ Division. All eight were awarded a battle honour for Dogger Bank. The fastest four – Meteor, Miranda, Mentor and Milne attempted to keep up with the battlecruiser action, but without success.

The Mentor was listed as part of the Tenth Destroyer Flotilla of the Harwich Force from March 1915 until January 1917.

The Mentor was badly damaged by a German torpedo while escorting a mine-layer operating in the Heligoland Bight. A hole was blown right through her, but the sea was smooth and she was able to return home safely.

On 27 March Laurel, Liberty, Leonidas and Lucifer were sent to patrol between the Mass and the North Hinder Light Vessel, to protect the Great Eastern Railway Company steamers which were still operating on the Harwich to Rotterdam route. The destroyers spotted a submarine at 4pm on 28 March, and spent the night attempting to keep her submerged. Six M class destroyers (Mentor, Manly, Morris, Milne, Mastiff and Murray) were sent to help, but early on 29 March the entire force was recalled to deal with a possible sortie by a German battlecruiser squadron. However it was soon discovered that the battlecruisers had returned to port, so the destroyers were sent back to patrol the same area. At 8.30am on 30 March the destroyers (by now raised to a total of 22) spotted U.24, but she dived and escaped. The patrols lasted until 5 April.

On 24 April 1915 the destroyer Landrail rammed the cruiser Undaunted during an operation to support a seaplane raid on the German coast. The Mentor started to tow the Landrail to safety but her tow line snapped. The Aurora had the same problem but eventually the Arethusa managed to get the Landrail to safety.

On 16 May 1915 the Admiralty ordered the Admiral in command at Devonport to send eight destroyers (Mentor, Milne, Moorsom, Myngs, Laforey, Leonidas, Loyal and Louis) to Liverpool, from where they were to escort the Mauretania and Aquitania when they left port at the start of a voyage on 18 May 1915. Once the escort mission was over the destroyers were to return to Devonport.

In June 1915 she was one of fourteen destroyers in the Tenth Destroyer Flotilla at Harwich, which was made up of all thirteen ships in the original M class and HMS Medea¸ which had been under construction for Greece and was taken over by the Royal Navy at the outbreak of war.

At the start of July 1915 the Tenth Flotilla (Aurora, Manly, Mansfield, Mastiff, Matchless, Medea, Mentor, Meteor, Milne, Minos, Miranda, Moorsom, Morris, Murray and Myngs) was operating from Devonport, escorting troop transports, either incoming from Canada or on their way to the Dardanelles.

On 2 July the Empress of Britain left Liverpool at the start of a voyage to the Dardanelles, carrying 4,500 troops. The Manly, Mentor and Miranda were sent from Devonport to escort her through the Irish Channel. Originally they were to escort her well out into the Western Approaches, but she was slow getting underway, so the Mentor and Miranda were ordered back at 5pm on 2 July to escort the Aquitania¸ which left Liverpool on 3 July with 5,939 troops onboard. The Manly stayed with the Empress of Britain until 9pm, and was then sent to Queenstown to take on oil. She was meant to go on to join the Aquitania, but ran aground off Queenstown in thick fog leaving only the two destroyers to escort the massive liner.

The Mentor and Miranda remained with the Aquitania until 5.10am on 4 July. 20 minutes later U-39 fired a torpedo at the Aquitania, but it missed. The U-boat was on her way back from a raid, so was unable to repeat the attack. On their way back to base the Mentor and Miranda picked up a call for help from the Anglo-Californian, and were able to go to her aid.

The Anglo-Californian was a horse transport bringing 927 horses from Canada to Avonmouth. At about 0800 she was attacked by U-39, attempted to escape, and for the next two and a half hours managed to keep the Germans at bay. At 10.30 the U-boat ordered her master to stop and abandon ship, and with his ship having already been damaged he decided to comply. However at this point a message arrived from Mentor and Miranda asking him to delay for as long as possible. As a result the Anglo-Californian got under way again, but by now the U-boat was at much closer range, and in the resulting bombardment 21 men were killed, including the ship’s master Lt Frederick Parslow RNR (who was award a posthumous Victoria Cross for his actions). When Mentor and Miranda arrived on the scene the U-boat was forced to dive, and the Anglo-Californian was able to reach the safety of Queenstown.

On 4-5 August 1915 the Mentor, Mansfield, Medea and Medusa supported the cruisers Arethusa, Conquest, Aurora and Undaunted during a sweep throight the Heligoland Bight as far as Terschelling off the north Dutch coast, in the hope of finding a German trawler and torpedo boat patrol that had been reported in the area. The cruisers sweep in line abreast with a gap of five miles between each ship, with one destroyer attached to each cruiser for boarding actions. No German ships were found and the force returned safely to Harwich.

On 17 August 1915 seven destroyers from the 10th Flotilla (Mentor, Minos, Moorsom, Miranda, Manly, Matchless and Medusa) along with four from the 4th Flotilla and the Harwich Light Cruiser Squadron escorted the minelayer Princess Margaret as she laid the first British minefield in the Heligoland Bight. The operation wasn’t a success. The force ran into part of the German 2nd Torpedo Boat Flotilla, and in the resulting clash the Mentor was hit and her bows blown off. In the confusion none of the other ships realised she had been damaged, and she was left alone. Her commanding officer, Commander Inman, used counter-flooding to get her onto an even keel, and then headed west. As the weather worsened she had to reduce her speed from 16 knots to 8 knots. Eventually she was spotted by two British submarines off the entrance to a gap in the minefields off the east coast, and was able to use their wireless to get back in touch with Harwich. She was back in port by the evening of 18 August.

The Princess Margaret withdrew when the clash began, and when she turned back she couldn’t find most of the escorts and hadn’t laid any mines when the entire force was recalled because a more powerful German fleet was believed to be in the area.

On 25 December the transport Van Stirum was sunk by U-boats on her way north past Milford Haven. In response two divisions of destroyers from Harwich were ordered to go to Portsmouth and then on to the South-west Approaches. Mentor, Moorsom, Manly, Melpomene, Mansfield, Myngs, Morris and Milne were sent, led by the Nimrod. By the time the reached Portsmouth they were no longer needed there, so they were sent on to Milford, where they were temporarily placed under the command of Admiral Bayly but only if there was more news of submarines. The U-boats were active again on 28 December, sinking the oiler El Zorro, but the weather was so bad that the M class destroyers were stuck in port part from a brief foray on 30 December.


In January 1916 she was part of the Tenth Flotilla, which was still officially based at Harwich, but that was rather widely scattered at the start of 1916. The Mentor was at Milford.

Early on 25 April the Manly, Meteor, Mastiff, Lightfoot and Termagant left Harwich with the cruisers Conquest, Cleopatra and Penelope in an attempt to intercept the German forces heading for Lowestoft. The Mansfield and Matchless followed soon afterwards and the Mentor at 3.05am. This flotilla sailed east at first, but when news arrived that the Germans were probably heading for Yarmouth, it turned north, and moved up the coast inside the British minefield. At 3.50am the German light cruisers were spotted, soon followed by the battlecruisers. The Commodore (T) turned south, in the hope that the Germans would follow, but at first they didn’t, and instead focused on the bombardment of Lowestoft. The British turned back north to keep in touch. At about 4.20 the German light cruisers had turned to the south-east, and soon after 4.30 the two forces opened fire. However the range was too long and nobody hit anything. However the German battlecruisers then came on the scene, and at 4.49 opened fire. The cruiser Conquest was hit by several 12in shells but the destroyers were largely untouched. At 4.56 the Germans turned east to begin the voyage home before the more powerful British forces heading their way could reach the scene. The Harwich force attempted to pursue, but without success, and the Penelope was torpedoed during the operation (although survived).

The Mentor was one of seven M class destroyers that put to sea on the night of 22 July to patrol the sea lanes between Felixstowe and Holland, part of a force of two cruisers and eight destroyers. The Manly was in the 1st Division, which took the lead, and early in the morning ran into three German destroyers that were out in an attempt to capture some of the merchant shipping on the same route. The division opened fire for a few minutes before the Germans were able to escape under cover of rain squall and smoke screen. Later the 2nd Division caught up with the entire German force of six destroyers, but after a short chase the Germans were getting close to the minefields off Zeebrugge, so the British withdrew.

On 20 September the Mentor collided with the liner SS Greenbatt in Dover Harbour.

In October 1916 she was part of the Tenth Flotilla at Harwich, which now contained all thirteen of the original M class ships, the flotilla leader HMS Nimrod and the ex Greek destroyer HMS Melpomene.


In January 1917 she was one of ten destroyers from the Tenth Flotilla that were still at Harwich, while the rest had been detached to Dover.

The Mentor was still assigned to the Tenth Flotilla until January 1917

By March 1917 the Mentor had been officially transferred to the Sixth Destroyer Flotilla at Dover. By July she had been joined by her entire class.

The Mentor was in the small Downs off Deal when the Germans carried out a destroyer raid into the Dover Straits on 17 March 1917 but didn’t get into action.

On 18 March the Mentor lost her starboard bower anchor and four shackles of cable in the Small Downs.

When the Germans raided into the Dover straits on 20 April the Mentor was part of the 2nd Sub-Division of the reserve or striking force. At about 11.30pm the Germans opened fire on Dover, but Admiral Bacon decided not to order the reserve force to move until the bombardment was over. The final order to sail didn’t come until 11.55, by which time the Germans were safely on their way home. The Mentor’s sub-division didn’t clear the harbour until almost 12.30. However the Germans did run into the flotilla leaders Broke and Swift, leading to one of the most famous incidents of the war, when the German destroyer G.42 and HMS Broke became entangled and the Germans attempted to board the Broke, leading to one of the few examples of a boarding action during the First World War. The Mentor arrived after the fighting was over, and picked up German survivors, then towed the Broke away from the burning German destroyer. The Mentor and the Lydiard then remained with the Broke while tugs came up to tow her to safety.

The Mentor was one of eight destroyers from the Sixth Flotilla that supported the bombardment of Zeebrugge on the night of 11-12 May 1917. Although this bombardment scored a number of near misses on its targets, Zeebrugge remained in operation as a German base.

In June 1917 she was part of the Sixth Destroyer Flotilla at Dover, but was undergoing a refit at Portsmouth.

At the start of June the Manly, Mentor, Moorsom and Miranda were part of the bombardment force that attempted to bombard Ostend. This force left Dover at 10pm on 4 June, while support forces left Harwich. The bombardment itself was carried out early on 5 June, and although the monitors Erebus and Terror fired 115 shells at the port little serious damage was done. The force then returned to base safely.

On 3 October 1917 the Mentor collided with a rowing boat at Dunkirk.


In January 1918 she was part of the large destroyer force at Dover, and was undergoing repairs at Immingham.

The Mentor took part in the attempted Ostend raid of 23 April 1918, where she was one of three destroyers that escorted the seven monitors allocated to the bombardment. During the bombardment itself she supported the Marshall Soult and General Craufurd.

In June 1918 she was part of the Sixth Destroyer Flotilla at Dover,

In November 1918 she was part of the Sixth Destroyer Flotilla, but was undergoing repairs.

In November 1919 was in the hands of a care and maintenance party in the Devonport reserve.

The Mentor was awarded battle honours for Dogger Bank, the Belgian Caost 1917/18 and Ostend (Zeebrugge) 23 April 1918.

Wartime Service
March 1915-January 1917: 10th Destroyer Flotilla, Harwich
March 1917-December 1918-: 6th Destroyer Flotilla, Dover


Displacement (standard)

Hawthorn Leslie: 1,055t

Displacement (loaded)

Admiralty design: 1,100t

Top Speed

35 knots


2-shaft Parsons independent reduction turbines
4 Yarrow boilers




271ft 6in oa




Three 4in/ 45 QF Mk IV guns
Two 1-pounder pom pom guns
Four 21in torpedo tubes with four torpedoes

Crew complement


Laid down

9 July 1913


21 August 1914


January 1915

Sold for break up

May 1921

British Destroyers From Earliest Days to the Second World War, Norman Friedman. A very detailed look at the design of British destroyers from their earliest roots as torpedo boat destroyers, though the First World War and up to the start of the Second World War, supported by vast numbers of plans and well chosen photographs [read full review]
cover cover cover

Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J (29 December 2022), HMS Mentor (1914) ,

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