By early April, relations between Germany and Russia were becoming critical, and both states had begun mobilizing their armies by the 14th with France and Italy following suit within the week. It nevertheless appeared for a time as though war between the Russian Empire and the Tripartite Pact could be averted, but the German ambassador in Moscow was overheard to make uncomplimentary remarks about the Tsar and his wife, and soon after was provided with his papers - and a declaration of war to bring back to Germany. The Kaiserliche Marine, its recovery from the defeat in the war with Britain hobbled first by the terms of the peace treaty and then by the limitations imposed by the Geneva Conference of 1913, was unprepared to challenge the Russian Baltic Squadron when, with the outbreak of the war, the Russian Empire announced the imposition of a blockade of Germany. Nevertheless, the Kaiserliche Marine was unwilling to stand entirely on the defensive, so ten of the sixteen Undine-class third class cruisers on overseas stations soon received orders to commence commerce raiding operations against Russian shipping and four small merchantmen were taken in hand to be equipped with minelaying equipment for service in the Baltic, each armed for intimidating unarmed merchantmen and the notional comfort of their crews with four antiquated 2" guns placed into the naval arsenals after being removed from ships decommissioned in the 1890s. Finally, with the limitations of the Geneva Conference lifted by the outbreak of war, the Reichsmarineampt ordered the battlecruiser Lutzow laid down to a revised Moltke design, and cancelled and re-ordered Seydlitz and Hindenburg as the second and third units of the Lutzow class.
The Kaiserliche Marine launched its first offensive naval operation in the Baltic in early May, sending five torpedo boats to attack targets of opportunity in the Gulf of Riga on the 9th. This operation was nearly thwarted by a lack of Russian shipping, but as the torpedo boats were departing the gulf they encountered a small Russian merchant ship almost under the guns of an 8" battery at the southern tip of Saaremaa and sank the ship while the coastal battery's gunners watched in helpless frustration, unable to train their guns around to bear on the German torpedo boats inside the gulf. The German torpedo boats then slipped out of the gulf under cover of a fog bank which fortuitously moved in just as the transport sank, denying the Russian gunners a chance at avenging their lost vessel.
Little over a month later, on the 13th of June, the first significant naval engagement of the war was fought just north of Gotland. A convoy returning to Germany bearing Swedish iron and timber, escorted by six of the 1,100t G11-class torpedo boats, ran into difficulty when one of the torpedo boats struck a drifting mine in the channel between Gotland and Havringe. Shortly afterwards, smoke on the horizon to the northeast resolved itself into five Russian cruisers - the scout cruiser Nadezhda and the second class cruisers Boyarin, Voevoda, and Svetlana, all of the eponymous classes, and the second class cruiser Vesta of the Florin class - and the convoy sent out a distress call, though not with much hope of eliciting an effective response as the nearest German naval bases were several hundred miles to the south. Fortunately for the convoy, however, the Roon-class second class cruisers Freya and Prinz Adalbert were nearby and, upon receiving the convoy's distress call, steamed at high speed to its reported position, arriving just as the Russian cruisers were coming into range of the convoy's escorting destroyers. Soon, Freya and Prinz Adalbert are engaged with Voevoda, Svetlana, and Nadezhda while Boyarin and Vesta continue to move against the convoy. In desperation, four of the convoy's escorting torpedo boats close with the two Russian cruisers and launch torpedoes even as three of the torpedo boats and two of the merchantmen sustain fatal damage from the Russian cruisers' 6" and 3" guns. Miraculously, both Boyarin and Vesta were struck by torpedoes between the E and G guns on the starboard side and were destroyed by massive explosions, believed to have been the detonations of the E and G magazines on each ship. The cruiser engagement to the north of the convoy broke off soon after Boyarin and Vesta exploded, with the Russian captains judging that the potential benefits of continuing the engagement did not outweigh the risk to their ships and the German captains seeing the safety of the remains of the convoy as their first priority. The convoy would suffer one last trial when it blundered into the Russian coastal submarine Delfin after nightfall, which torpedoed and sank one of the four surviving merchantmen before escaping into the darkness.
In July, the Russian Nadezhda-class scout cruiser Pamyat Merkuriya intercepted and attacked the third class cruiser Undine northeast of Shanghai after a Russian merchantman sheltering in that city's harbor reported Undine's presence in the area. In a hard-fought engagement, Undine sank Pamyat Merkuriya but herself was badly damaged and only just managed to make port at Tsingtao for repairs. Undine would be out of action for the next three months. A further blow to the Kaiserliche Marine's war on Russian maritime commerce came later that month, when one of Undine's sisterships, Nurnberg, ran out of fuel after a navigational error in the South Pacific and had to be scuttled as she drifted onto the Great Barrier Reef off the Australian coast. Meanwhile, the Reichstag, after much debate, approved the issuance of a round of war bonds to fund the construction of two new second class cruisers, Prinz Heinrich and Friedrich Carl, to supplement the eight Roon-class cruisers serving in the Baltic or with the Hochseeflotte.
Russian and German second class cruisers clashed for the second time in this war when on 4 August the Roon-class cruisers Freya and Roon encountered the Zhemchug-class second class cruiser Yakhont and the second class cruiser Svetlana, escorted by three destroyers, off Libau, Latvia. The faster and more heavily armored German cruisers soon gained the upper hand over the older Russian cruisers, and first Yakhont and then Svetlana were sunk by the 6" guns of the German cruisers. Two of the Russian destroyers were also sunk during the engagement, although the third escaped despite heavy damage. This defeat lead the Russian Baltic Squadron to commence a series of patrols with its battlecruisers and first class cruisers, meant to hunt down and destroy the German second class cruisers.
With the Hochseeflotte unwilling to release any of the the newly-commissioned battlecruisers or the battleship Weissenburg for operations in the Baltic until their crews met the prewar efficiency standards of the cruiser fleet, the Baltic Squadron elected not to challenge the heavy Russian patrols, and as August came to a close the Russian Baltic Squadron's commanders were becoming frustrated with their fruitless patrols and with the increasing harassment of their cruisers on blockade patrols in the North Sea. Accordingly, plans were set in motion for a raid on Helgoland, and the Rymnik-class battlecruisers Hotin and Fokshani, the battlecruiser Izmail, and the small first class cruiser Gromoboi were assembled at Riga. This force set out on 30 August but ran into difficulties almost immediately, when a blade failure in one of the turbines aboard the battlecruiser Fokshani required the force to return to port. Fokshani was removed from the operation, and the force set out again on 1 September, reaching the Skagerrack on 3 September undetected by German coastwatchers and light patrol craft thanks to inclement weather and heavy fog. There, however, they encountered Unterseeboot 10, lying in wait for Russian cruisers passing into the North Sea or returning from blockade patrols, and U-10 scored the German submarine force's first major victory of the war when it torpedoed and sank Gromoboi and a destroyer as the Russian raiding force passed into the North Sea. U-10 successfully evaded the remaining four destroyers of the Russian raiding force and reported the Russian heavy ships' entrance into the North Sea later that day, though the report misidentified the Russian battlecruisers as Kinburn-class ships.
As 4 September dawned, new orders were hand-delivered to the battlecruisers Goeben and Derfflinger at Wilhelmshaven just before these ships cast off for a training exercise near Helgoland, and the naval dockyard erupted into a flurry of activity as several hundred 12" training shells were removed from the battlecruisers in exchange for live ammunition. By noon, the battlecruisers were once again ready to depart and soon set off into the Bight to seek out the Russian battlecruisers which had been sighted entering the North Sea. Around 1600 GMT, as the German battlecruisers passed northeast of Helgoland, coastal patrol craft to the southwest reported coming under attack by heavy ships and the German capital ships altered course accordingly. Soon, German and Russian battlecruisers met for the first time, exchanging fire until darkness and battle damage forced them to break off. The battlecruisers Hotin and Goeben were severely damaged in the hour-long engagement, and the torpedo boats escorting the German battlecruisers were detached to seek out and finish the Russian cripple in the twilight, finding Hotin and putting three torpedoes into the settling vessel just after her crew abandoned her. Goeben, though flooding uncontrollably and heavily down by the bow, managed to make Helgoland and reach the repair yards there around midnight, and at around the same time a patrolling torpedo boat to west-southwest encountered Izmail and put a torpedo into her side. Izmail, however, survived, and despite the best efforts of the submarine arm and the torpedo boats on patrol in the Baltic would return to Riga with no further damage.
With the loss of Hotin and Gromoboi added to the earlier cruiser losses, the Russian Navy no longer believed itself capable of maintaining the blockade of Germany and began committing its cruisers to commerce raiding operations instead, though without formally ending the blockade. By December, enough Russian cruisers had been dispersed into the Atlantic, Indian, and Pacific Oceans that the Russian Baltic Squadron was no longer able to prevent the Kaiserliche Marine from blockading Russia's Baltic ports. This dispersal of Russian cruiser forces nevertheless created problems for the Kaiserliche Marine's overseas squadrons, with the Undine-class third class cruiser Danzig being heavily damaged in an engagement with the Russian Boyarin-class second class cruiser Rynda off Shanghai in October, and November seeing the loss of Coln to a mine off Duala, Cameroon and the sinking of Dresden by the Boyarin-class second class cruiser Oprichnik near Java. To replace these losses, the Admiralstab ordered the construction of four new third class cruisers - Hela, Niobe, Gefion, and Gazelle - to a slightly-revised Undine class which gives up two of the 4" secondary guns for increased oil bunkerage and more robust machinery.
As the new year dawned, the Russian Navy stepped up submarine operations, and on 3 January the Roon-class second class cruiser Leipzig was torpedoed twice as she left Kiel for patrol in the Baltic. The ship was saved when her crew intentionally grounded her near Schonberg, but the ship would be out of action for the next five months, and a month later her sister Victoria Louise would be torpedoed in the same area, though a faulty torpedo warhead - or perhaps simply an older-model torpedo - meant that she could return to service after two months instead of the five necessary to restore Leipzig. In the same period, the Russian scout cruiser Diana of the Avrora class was sunk in the North Sea by the second class cruiser Freya, and a flotilla of seven German torpedo boats surprised and sank a Russian merchantman off Reval despite the proximity of ten Russian destroyers.
March 1917 passed almost without incident, and as if to make up for it the Russian Navy's submarine arm torpedoed and sank RMS Lusitania on 12 April with heavy loss of life near Ireland, greatly angering the British and American public. The resulting curtailment of Russian submarine operations lead the Baltic Squadron to attempt a raid on German Pomerania, sending the entire Russian battle line south and catching the German battleships Weissenburg and Hannover and the battlecruisers Goeben, Moltke, and Derfflinger en route to Danzig. Perhaps surprisingly, no ships other than destroyers and torpedo boats were sunk on either side, but the German battleships and battlecruisers and the Russian dreadnoughts were severely damaged, with Weissenburg and Hannover suffering particularly badly as they had borne most of the fire from the Russian battle line despite the three German battlecruisers standing in the battle line behind them.
May and most of June passed without noteworthy incident, though on 30 June the armed merchant cruiser Syria, on blockade patrol in the North Sea, encountered the Russian scout cruiser Nadezhda. Its four 2" guns proved as worthless as expected against the Russian warship and Syria was soon sunk. Syria's loss led to the reassignment of the remaining three AMCs to antisubmarine patrol in coastal areas, though it is generally though that their armament was inadequate even for engaging surfaced submarines. The Hochseeflotte's cruisers and even the battlecruiser Goeben were assigned to blockade patrol, and in several minor actions the first class cruiser Knyaginya Olga, the scout cruiser Nadezhda, and the second class cruiser Oprichnik are sunk.
Towards the end of November, the Hochseeflotte agreed to loan its three battleships and three of its second class cruisers to the Baltic Squadron for a raid on the island of Hiiumaa, in which the Kaiserliche Marine demonstrated that its failure in the war against Britain five years earlier had taught it nothing about signals security. Russian dreadnought battleships and battlecruisers were waiting for the German force as it approached the raid target in the darkness, and the Roon-class cruisers Hertha, Freya, and Leipzig were ripped apart by 12" shells fired at short range when they blundered into the Russian battle line. Three German torpedo boats were lost during torpedo attacks which allowed the German battleships to withdraw safely, and just four Russian capital ships were damaged, only one - the predreadnought battlecruiser Kinburn - seriously. A bit over a month later, reinforced by the Hochseeflotte's three battlecruisers, the German Baltic Squadron attempted another major operation, this time encountering the Russian battle line near Gotland in midafternoon on 29 December in an indecisive engagement that left the Russian dreadnought Sisoi Veliki heavily damaged and the Russian dreadnought Imperatritsa Mariya and the German battleships Weissenburg and Hannover moderately damaged. Once again, the German battlecruisers standing in the line of battle behind the battleships escape serious damage.
The first naval action of 1918 occurred when the Roon-class second class cruiser Prinz Adalbert intercepted the Russian Ameytst-class second class cruiser Sapfir on 7 January while on blockade patrol near the Denmark Strait. Sapfir withdrew before Prinz Adalbert and launched a pair of well-aimed torpedoes at the pursuing German cruiser, both of which struck home, and the German ship soon sank beneath the waves. Three days later, the Reichstag approves funds for a new battlecruiser, Mackensen, an enlarged Lutzow armed with six 16" guns instead of Lutzow's six 15" guns. The remainder of January and much of February passed without incident, but then on the 24th the Roon-class cruiser Amazone intercepted and sank the Russian Boyarin-class second class cruiser Vladimir while on blockade patrol and was itself nearly sunk when torpedoed by the Russian coastal submarine Sazan as it returned to Wilhelmshaven. This resurgence of Russian submarine activity, however, was curtailed in March after the packet steamer RMS Leinster was torpedoed and sunk by a Russian submarine outside Dublin, Ireland on the tenth. Eight days later, the German second class cruiser Amazone, recently released from the shipyards after being torpedoed in February, is sunk by the small Russian first class cruiser Knyaz Vladimir several hundred miles to the north.
Late in April, as the Hela- and Prinz Heinrich-class cruisers commission, the Reichstag approves funds for a second Mackensen-class battlecruiser, Furst Bismarck. A bit over a week later, on 2 June, the Roon-class cruisers Victoria Louise, Berlin, and Roon catch the Russian second class cruiser Sapfir and three destroyers near Libau, Latvia, sinking Sapfir and two destroyers in a brief engagement. July and August pass without incident, and September looked to do the same until, on the 28th, the recently-commissioned third class cruisers Hela and Gazelle raid Russian coastal shipping near Hango, failing to sink any merchants but severely damaging the Russian Zhemchug-class second class cruiser Rubin and the AMC Vilna. Both of the small German cruisers sustain moderate damage during the engagement. On 1 November, the battlecruiser Hindenburg becomes the first of the three Lutzow-class battlecruisers to commission, and six days later the recently-commissioned second class cruiser Prinz Heinrich was torpedoed and severely damaged on its first war patrol in the Baltic when it and the Roon-class cruiser Victoria Louise encountered and pursued a pair of Russian destroyers near Danzig. Little over a month later, the last major engagement of the year occurred near Christiansø, when the German battlecruisers Goeben, Derfflinger, and Moltke encounter the Russian Kinburn-class predreadnought battlecruisers Kinburn and Ochakov, accompanied by the Zhemchug-class second class cruiser Rubin. All three Russian ships were sunk at the cost of moderate damage to Moltke and light damage on Derfflinger, but a machinery breakdown due to battle damage as the German battlecruisers returned to port left Moltke vulnerable to the Russian coastal submarine Sazan, which torpedoed and sank the German capital ship about 50 nautical miles north-northwest of Danzig.
Out-of-'character' notes:
Looking at the treaty battleships that the other powers built, I'm becoming more convinced that I should have built the Weissenburgs to the treaty limit as 8x12" or 9x12" treaty dreadnoughts rather than building them as 6x12" 'predreadnought' battleships under the treaty limit. On the other hand, I'm uncertain that I would've built all three of them if I hadn't kept the size down, and I should hopefully have better battleships before the next war anyways.
Russia came into the war with 12 predreadnought battleships, including I think two classes that I didn't include in MoreShip5 because I don't remember which classes they were and didn't write them down somewhere, but they were scrapping them throughout 1916 and 1917 and now don't have any left. That's part of the reason why I was able to start blockading Russia at the end of 1916 - a large part, probably, because I didn't sink a whole lot, though the dispersal of their cruisers at the end of 1916 didn't hurt, either. I'm half-disappointed that I'm blockading Russia, now, since the blockade more or less means my handful of submarines aren't doing much of anything except getting sunk, but on the other hand it meant that I could drop them from the construction program since maintaining the strength of the submarine force isn't really necessary with Russia blockaded.
Italy has somehow managed to lose a dreadnought battleship (Attilio Regolo, 23,200t 10x12" Dreadnought configuration), a treaty battlecruiser (Abruzzi, a fourth member of the Basilicata class, commissioned in 1916), and a predreadnought battleship (Giulio Cesare, 15,000t 4x12" 14x6") in engagements with the Russian Navy, though if I recall correctly they're also responsible for the only Russian battleship lost thus far in the war (Pobeda, an Imperator Aleksandr III-class semidreadnought) and for sinking the battlecruiser Izmail (8x12" AHIY configuration). This, despite Italy not sending anything to Northern Europe and Russia not sending anything but AMCs to the Mediterranean so far as I am aware. Allied war 'participation' amuses me, sometimes.
The Seydlitz and Hindenburg only had one turn of work done on them when I cancelled and re-ordered them as Lutzows, so fortunately only a relatively small amount of funding (about 5.2M) was wasted, but I'd probably have cancelled them even if they had been a bit more complete, as AoN armor was developed the turn that the war broke out and 6x15" battlecruisers are a lot more valuable than 6x12" battlecruisers.
Lutzow could have been the first 16" battlecruiser I laid down, as I had 16"/Q0 and 15"/Q0 guns at the time, but fitting the 16" guns with all the armor I wanted would've required Lutzow to be about 3000 tons heavier and I don't think there's enough of a difference between 15"/Q0 and 16"/Q0 that the heavier gun is necessarily the right choice. Mackensen got 16" guns because when I laid it down the choice was between 15"/Q0s like I have on the Lutzows and 16"/Q1s, which Germany had developed a couple turns before enough funds became available for me to lay Mackensen down.