maybe over the Philippines
It's not as directly as the question might want but what about the Crimean War? Even Sardinia got involved in that. Surely having Spain pile on isn't too far fetched?
How about the War of Austrian Succession?
In 1742, the new Viceroy of New Spain, Pedro Cebrián, arrives in Mexico City. He is aware that the Russian Empire is at war with Spain's ally, France. Furthermore, during tenure as ambassador in Vienna, he had heard rumors about Russian fur traders being active in the New World, though not all those rumors agreed that there were settlements there. Hoping to find favor with this master, Philip V, the Viceroy commissions two galleons to sail from Acapulco to discover these settlements, and harry them if they are found.
The leader of the expedition is initially quite skeptical. However, diligent work by the viceregal archivist turns up some charts from Juan de Fuca's 1592 expedition. Though the 16th century explorer was a bit hazy about the distance, this convinces Cebrián that it is possible to venture so far north. The leader of the expedition reluctantly agrees.
The expedition leaves Acapulco in February, 1743, and heads north, staying within sight of land. However, before the ship manages to reach the straight that Juan described in his map, the ships are taken by the Alaska Current, and borne west, away from land, and, by the crews' reckoning, beyond all hope. After nearly two months in the open ocean, in August 1743, the crew spies land.
Not having the slightest idea where they are, the captain agrees to call off the expedition, and begins cautiously sailing south. As luck would have it, a few days later, the lookouts spy a settlement. Amazingly, the flag over the settlement is the blue, white and red tricolor of the Empress of Russia!
Taking this to to be a sign from God, the crew disembarks, and enters the small village under arms. There are fewer than 100 souls present at Petropavlovsk, and none are eager to fight, not even being aware of the war going on so far to the West.
The settlement surrenders, and the expedition members help themselves to every bit of fur and salmon they can find. By consulting the fur traders' crude maps, they determine their approximate location, and decide that it would be far safer to sail for the Philippines than attempt to repeat their journey.
By the time news reaches the St. Petersburg, it is 1745. Russia has exited the war, but the court is nonetheless annoyed. Russia re-enters the war in 1748, in time for its troops to take place in a few desultory engagements before the peace treaty is signed. The peace treaty contains a clause ending the state of war between the King of Spain and the Empress of Russia.
Philip V learns of "his" expedition through his intelligence network in late 1745. His letter asking for an explanation from his Viceroy in New Spain is the first news that Pedro Cebrián has heard of his expedition in two years. The galleons that set forth from Acapulco will never be heard from again, though two centuries later scholars will link it to rumors of several "black ships" that were sighted off of Hokkaido in 1744.
Just as the title says. With a PoD between 1815 and 1900, make Russia and Spain go directly to war with one another.
Wouldn't be too hard. Some 'damn thing in California' could well escalate into something bigger between the two countries.
Competing claims in California (Fort Ross in Sonoma County vs. the Viceroyalty of New Spain) leading to disputes leading to skirmishes leading to low-level war. Maybe Spain raids a few Russian settlements in Alaska and Siberia and this leads to some retaliation by the Russian fleet in the Philippines, the Pacific islands or even Spain itself.
It's not going to be a massive war but hey, you didn't say that was necessary.
The Russians definitely need a stronger fleet that could be on par with the Spanish fleet for sure.
? The Russians have a good enough fleet to challenge Spain in the Baltic since the Archipelago Expedition at the very least. What they don't have in a tradition of sending warships around the world, but by 1815 they certainly do and Spain is temporarily really weak following the Napoleonic wars while Russia is temporarily #2 in the world.
Russia is always going to have a problem with bases though, regardless of how many hulls they have afloat. That's difficult to change.
? The Russians have a good enough fleet to challenge Spain in the Baltic since the Archipelago Expedition at the very least. What they don't have in a tradition of sending warships around the world, but by 1815 they certainly do and Spain is temporarily really weak following the Napoleonic wars while Russia is temporarily #2 in the world.
Russia is always going to have a problem with bases though, regardless of how many hulls they have afloat. That's difficult to change.
The 1809 numbers, The Russian fleet might be lower by 1815; since Anglo-Russo war was still happening while Trafalgar already passed. You can actually see Russians losing Ships of the Line by 1809 from 48 in 1803 and 60 in 1798.
How about the War of Austrian Succession?
In 1742, the new Viceroy of New Spain, Pedro Cebrián, arrives in Mexico City. He is aware that the Russian Empire is at war with Spain's ally, France. Furthermore, during tenure as ambassador in Vienna, he had heard rumors about Russian fur traders being active in the New World, though not all those rumors agreed that there were settlements there. Hoping to find favor with this master, Philip V, the Viceroy commissions two galleons to sail from Acapulco to discover these settlements, and harry them if they are found.
The leader of the expedition is initially quite skeptical. However, diligent work by the viceregal archivist turns up some charts from Juan de Fuca's 1592 expedition. Though the 16th century explorer was a bit hazy about the distance, this convinces Cebrián that it is possible to venture so far north. The leader of the expedition reluctantly agrees.
The expedition leaves Acapulco in February, 1743, and heads north, staying within sight of land. However, before the ship manages to reach the straight that Juan described in his map, the ships are taken by the Alaska Current, and borne west, away from land, and, by the crews' reckoning, beyond all hope. After nearly two months in the open ocean, in August 1743, the crew spies land.
Not having the slightest idea where they are, the captain agrees to call off the expedition, and begins cautiously sailing south. As luck would have it, a few days later, the lookouts spy a settlement. Amazingly, the flag over the settlement is the blue, white and red tricolor of the Empress of Russia!
Taking this to to be a sign from God, the crew disembarks, and enters the small village under arms. There are fewer than 100 souls present at Petropavlovsk, and none are eager to fight, not even being aware of the war going on so far to the West.
The settlement surrenders, and the expedition members help themselves to every bit of fur and salmon they can find. By consulting the fur traders' crude maps, they determine their approximate location, and decide that it would be far safer to sail for the Philippines than attempt to repeat their journey.
By the time news reaches the St. Petersburg, it is 1745. Russia has exited the war, but the court is nonetheless annoyed. Russia re-enters the war in 1748, in time for its troops to take place in a few desultory engagements before the peace treaty is signed. The peace treaty contains a clause ending the state of war between the King of Spain and the Empress of Russia.
Philip V learns of "his" expedition through his intelligence network in late 1745. His letter asking for an explanation from his Viceroy in New Spain is the first news that Pedro Cebrián has heard of his expedition in two years. The galleons that set forth from Acapulco will never be heard from again, though two centuries later scholars will link it to rumors of several "black ships" that were sighted off of Hokkaido in 1744.