Royal Navy Monitors:
The Foreigners
By David Hughes
March 2015

When war broke out in 1914 the Admiralty did what it always did at such times — it seized any warships of conceivable value being built for foreign navies. Among them were three small river monitors that had been constructed for Brazil, the Javery, Madeira and Solimòes and two Norwegian coast-defence battleships, the Björgvin and Nidaros. All five would be converted into monitors.

The three Brazilians (up for sale after the rubber boom collapsed) were perfectly suited to their original task, with a draft of less that five feet and a freeboard of only two feet, quite sufficient for the waters of the Amazon. They were also well armed with a twin 6-inch turret forward and a pair of 120-mm howitzers in the stern, protected by a three-inch belt. The Royal Navy made no major changes (very unusual and a comment on their quality), renamed them as HMS Humber, Mersey and Severn and sent them straight into action, bombarding the German troops advancing along the coast of Flanders. Their shallow draft proved immensely useful by allowing them to get close to the coast, as their guns had limited elevation and could only reach about 10,000 yards. It also saved Severn when a torpedo fired by the U.8 went straight under her! By November the targets were protected or out of reach, especially as the continuous firing meant that the guns were worn and could barely reach 8,000 yards.

The monitor Mersey, originally ordered as Brazilian river monitor Madeira.

In early 1915 the guns were replaced. Mersey and Severn had the turret removed with single 6-inch guns mounted fore and aft. Humber, whose guns were in better shape, kept the turret, yet was also given a stern 6-inch, making her much more powerful than her sisters. The new plan was to use them as river-gunboats again, assuming that once the Dardanelles had been taken they would sail up the Danube, causing consternation to the Austro-Hungarian Empire. As there were very grave doubts over their ability to survive heavy seas the crews were removed and the ships towed to the Mediterranean, each behind a pair of tugs. They arrived safely to discover that the Mersey and Severn were now ordered to sail "with all despatch" to East Africa to handle the German light cruiser Königsberg, safely ensconced up the Rufiji River Delta.

They now became the only Royal Navy monitors to sink an enemy vessel, not without difficulty as the 105-mm guns of the Königsberg outranged their own heavier weapons. Mersey got the worse of the first exchange, hit twice and with her forward gun knocked out. In the end victory was determined by spotting and when the German ground lookouts were killed and two aircraft became available to help the monitors the end was inevitable. However, from beginning to end, the monitors had to fire no less than 837 6-inch shells! Meanwhile Humber was called into service when German submarines sank the pre-dreadnought battleships Majestic and Triumph. Secure in the knowledge that no torpedo could possibly hit her, she anchored off Anzac Beach duelling with Turkish batteries when they set up in positions that allowed direct fire against the Australian and New Zealand troops. After the Dardanelles were evacuated she was then used to bombard Senussi positions along the Egyptian coast near Mersa Matruh.

HMS Severn, the former Brazilian Solimoes.

These episodes were the high point of their career and for the rest of the war all three rested in ports in the Eastern Mediterranean. When it ended they did at last move up the Danube to Galati while Humber was then ordered to Northern Russia. In May 1919 she arrived to become part of the Archangel River Flotilla supporting the Allied and White Russian troops. The most exciting moment came when the White Russians revolted just as the Dvina River was at its lowest. It was necessary to remove her 3-inch belt armour before she could be gingerly sailed north to the sea. Humber was towed back to Britain in September 1919 and all three had gone to the wreckers two years later.

The two Norwegians were built for a very different purpose, being coast-defence ships which could trade endurance for armament and armour. They carried two 240-mm in single turrets, as well as with four 150-mm (these also in single turrets one on each beam and one super firing over each main gun), were protected by a 7-inch belt and a 2-inch deck and yet weighed less than 5,000 tons and could achieve 14 knots. Both ships had been launched in 1914, but completion was delayed when the Admiralty decided to give priority to the "light battle cruisers" Courageous and Furious. Progress resumed in 1917 as the need to help the Army in Flanders became more and more important, but with several significant changes. One was to add a bulge, needed if the draught was to be held steady as more weight was added. The major change was to the armament as it was impossible to maintain ammunition and parts for their "foreign" (actually built in England by Elswick) guns.

HMS Glatton, the former Norwegian Bjørgvin.

Re-working the secondary armament was easy, simply boring out the existing 150-mm barrel to match the 152-mm of a British 6-inch gun. The process was reversed with the main armament. An inner tube was inserted into the 9.45-inch barrel, reducing it to the 9.2-inch for which Royal Navy ammunition was available. However it was also desired to increase the range as German heavy gun batteries were making life very uncomfortable for the monitors operating off Flanders. Fortunately the new liner meant that the barrel could take a heavier charge. By also increasing the elevation to 40-degrees and by using a new ballistic cap it was possible to increase the range to a phenomenal 39,000 yards. Only the monstrous 18-inch gun, only fired in anger from the monitors Lord Clive and General Wolfe, could match this and there was some evidence that it was less accurate as well as weighing well over ten times as much! Although the Royal Navy did not use the 9.2-inch again this new technology did not go to waste. It was made available to the British Army which then, between the wars, used it to greatly improve the performance of its own 9.2-inch coast-defense guns.

The two ships now became HMS Glatton and HMS Gorgon (both shown in both Norwegian and Royal Navy colours in the game Jutland), two knots slower and two feet deeper than before, but ready for action. Alas the class would become best known not for their long-range gunnery but for a self-inflicted disaster. In September 1918 the Glatton was anchored in Dover Harbour getting ready for her first bombardment mission when her 6-inch magazine exploded and the ship caught fire. As an ammunition ship was nearby it was decided to sink Glatton before the fire reached her main magazine and the subsequent series of sympathetic explosions destroyed most of Dover. The little ship (no bigger than a small cruiser) proved resistant. Two 18-inch torpedoes were stopped by her bulge and she only sank when two 21-inch were fired into the hole they had created. The magazine was next to the boiler room and it was discovered that the stokers had piled red-hot used cinders against the wall that separated them. It seems that the insulation in the wall was inadequate, leading to an increase in magazine temperature that eventually detonated the cartridges, killing or injuring half her crew.

Her sister ship had already been action, firing at a range of 36,000 yards at German inland installations with her main guns. She usually operated with the Lord Clive and General Wolfe as part of the very long range monitor division. After the war the Royal Navy had no use for the ship and tried to dispose of her. She was offered back to Norway, which would gladly have accepted, except that the bulge that had been added to the original design made her too wide to fit into the largest dry-dock available. Peru expressed vague interest while Romania (as mentioned in Black Sea Fleets) did offer to buy her and six reconditioned M Class destroyers. The deal collapsed and Gorgon was used as an effective bomb and shell test ship until finally broken up in 1929.

Will Glatton prove as tough in action as she did in accident?
Order Great War at Sea: Jutland and find out!