The launch of the H.M.S. Dreadnought in 1906 was quite a big deal. The new “all-big gun” design of the battleship was revolutionary for the era, not to mention her steam-turbines – never having been used on a warship of her size before.
As such, she gave her name not only to the class of ship (of which she was the only one, the Bellerophon-class immediatly following her with minor improvements to the design, mainly for torpedo protection), but to the entire style, as all those preceding her were immediately seen as obsolete.
The HMS Dreadnought sported a compliment of ten 12-inch guns – which Togo seems to use as a playground – paired into five turrets, four guns facing aft, two guns to the bow, and two each on either flank, allowing an eight gun broadside to either side.
Visible on top of the turret is one of the 12-pndr guns originally placed atop the casements. This were later abandoned when it was realized not only that the crews were left terribly exposed when manning them, but also that the vibrations of the main guns damaged their smaller compliments.
Photo part of the collection of the Imperial War Museum.