What successful northern naval victory stongly proved the value of sea power?

The Battle of Tsushima fought in the Tsushima Straits on 27 May 1905, did not prove the value of sea power. Tsushima simply proved that the "faster all big-gunned battleship" was superior to slower moving mixed battery battleships that were being designed and built at that time. The battle resulted in Great Britain laying the keel of HMS Dreadnaught in October of 1905. HMS Dreadnaught was the starting point of the world's new "Arms Race" between the superpowers of the early 20th century. When HMS Dreadnaught was launched in 1906; (from 1906 onwards) all new battleships in the world were referred to as, "Dreadnaughts." HMS Dreadnaught was fast and equipped with all large caliber guns (12 inch).