I can answer as to the specifications of those three ships and a smaller summary of the Swedish Navy during WW1, but it might give you a general idea.

The three Swedish ships of the Sverige-klass were built slightly differently due to modifications and purpose and were also modified over time. Their classification is apparently a bit different depending on language, since in Sweden they are known as “1.klass pansarbåtar” or just “pansarskepp” which translates to “armoured ship” while in English they seem to be known as “coastal defence ships”.

HMS Sverige:

• Armament:

  • 4x main 283 mm guns in two twin-turrets
  • 8x 152 mm guns in one twin and six single turrets
  • 4x 75 mm AA cannons
  • 2x 57mm small guns
  • 9x 6.5 mm MG
  • 2x torpedo tupes
  • Deplacement: 6,852 ton/7,688 ton fully loaded
  • Speed: 22,5 knots
  • 200 mm armour on the sides, 28 mm deck armour, 200-175 mm on the turrets, 100 mm on the citadel

• Crew: 427 men, 443 as a flagship

The two sister ships were slightly lighter and faster, their bows designed for icebreaking and having two propellers instead of Sverige´s four.

In 1901 the Navy wanted to build a fleet with stronger guns than ships of the same class/size in other navies, thereby forcing enemies to commit more valuable battleships which were slower than the Swedish ships. At this time Finland was undergoing a Russification campaign and Norway was increasingly trying to become independent, which increased the perceived need of a fleet able to operate along the coastline and away from it. So in 1905 when the union with Norway was dissolved and the naval arms race (with Russia and Germany being two close neighbours across the Baltic) the Swedish fleet, which had been considered to be comparable to other nation´s ships, had to be modernized. This led to plans to build the armoured ships which became the Sverige class, but they were delayed due to changes in government, which meant that they weren´t finished until the end of WW1 and even then became quickly unmodern.

The coastal fleet consisted, at the start of the war, of

• 9 armoured ships/coastal defence ships
• 1 “pansarkryssare” (armoured cruiser)
• 3 torpedo cruisers
• 8 destroyers
• 35 torpedo boats
• 5 submarines

This fleet was considered unmodern in both Sweden and other countries. Germany and England only considered the HMS Sverige (finished just before the end of the war), the submarines and the destroyers modern. Five more submarines were added within a year of the start of the war. Apart from these ships there were local forces based along the northern coastline and the major naval bases and cities, consisting (in total) of:

• 3 armoured ships
• 10 modernised 2nd and 3rd class armoured ships (the others were 1st class)
• 2 torpedo cruisers
• 10 torpedo boats
• A few gunships

Comparing the HMS Sverige´s 283mm guns to some German ships, you have the Nassau-class which were built with 280 mm guns, and those were dreadnoughts. (although the other German dreadnought classes had larger calibers.) The other Swedish armoured ships had between 210 mm and 250 mm guns. The German pre-dreadnought battleship, the SMS Schleswig-Holstein, had four 280mm guns, which shows that the Swedish ships, though unmodern, were probably not entirely defenseless. But of course, you have to factor in number of guns, escorts, armour, and amount of ships. A German-Swedish naval battle during WW1 would most likely be in the Baltic, where only the Russians could potentially help out, and thus it might mean that Sweden would stand a better chance (due to the German navy having the bulk of its fleet on the North Sea coast) or a much worse chance due to Germany being able to concentrate its fleet without fear of the British, since the Kiel canal allowed relatively safe and easy fleet relocation.

There weren’t that many naval battles in the Baltic during the war, but taking the battle of Moon Sound in the Gulf of Riga in 1917 you had a German force of 1 battlecruiser, 10 battleships, 9 light cruisers, 50 destroyers and 6 submarines against a Russian force of 2 pre-dreadnoughts, 3 cruisers, 3 gunboats, 21 destroyers and 3 English submarines. Either side of that battle would have given Sweden a very hard time, and in that battle the Russians didn’t even have their dreadnoughts. But then again, the Swedish fleet was supposed to deter incursions and breaches of neutrality, as well as making sure a potential enemy would have to commit a serious force to attack, not establishing maritime dominance.

Sources:

• Benbow, Tim. (2009) Första Världskriget Del 6: Sjökriget 1914-1918 Från Falklandsöarna till Zeebrugge . (Olsson, Staffan & Lindh, Lars transl.) Dubai, Svenskt Militärhistoriskt Bibliotek.

• Hofsten, Gustaf von & Waernberg, Jan. (2003) Örlogsfartyg Svenska maskindrivna fartyg under tretungad flagg. Luleå, Svenskt Militärhistoriskt Bibliotek.