unless u weaken the British Navy or have the Germans gain a Naval upperhand in the beggning the war, both navies would stay at port. here is my idea on how to do this.
Admiral Jackie Fisher dies in the China Wars of 1859-1860. (in OTL he was injured but not killed). Thus the Admiral that would reform the British Navy to suit modern needs is out of the picture. The British, still feeling superior from its Navy exellence from the Napoleon Wars, barley update its Navy. All upgrades are done slowly. Charles Beresford takes over the Admiralty (OTL he instead fueded with Fisher and never made it to the Admiralty). The Dreadnaught is started after American and Japanese style ships are made and after the British gain intel that the Germans are creating a dreadnaught too. Im guessing that the British and the German Dreadnaughts would thus be made around the same time. Most of the older ships that Fisher decommissed instead stay in service, spreading the Royal Navies manpower thin. Submarines are not really introduced into the Royal Navy for the Admiralty did not enjoy a ship that could strike a cowardly blow at the enemy. Also the British are slower in creating their own destroyer and probally copy Spanish and Japanese style destroyers. Thus when World War 1 roles around, the British Navy is not at its top peak of excellence. The Royal Navy moves to blockade the German ports and the High Seas Fleet goes to assault them. The British Navy move in close to fire (OTL Jacky Fisher was the one that put an end to this practice), while the suprised German Captains begin to fire at long range. While the Royal Navy is able to stop the German breakout, the Royal Navy suffers terrible casaulties. This leads to holes in the blockade and ships from the High Seas Fleet are free to move out and assault British Commerce. This may prevent the sinking of the Lusitania as well as lessing the chance that the USA would enter the war. Lastly it would also allow the spread of German Proproganda, bathing the Neutral World in German and British proproganda instead of just British.