In the latter half of the 19th century, ships began to transition from wood to iron and many engineers thought the time was ripe to experiment new forms. John Elder, a Scottish shipbuilder, advocated that making a ship wider in the beam would allow it to carry heavier and more powerful guns. Such a design would also have a shallower draft and only a moderate increase in power would be required to match the speed of a normal ship. The concept greatly interested Andrei Alexandrovich Popov, a rear admiral of the Imperial Russian Navy, but he took the idea to the extreme resulting in one of the most curious looking ships ever built.
Popov proposed a ship whose beam matched its length. There were to be no straight sides. Instead, the hull was to curve all around the ship. In other words, a ship with a completely circular hull and a flat bottom. The circle is an amazing shape. It encompasses the maximum area at minimum perimeter. Popov argued that the circular design would offer the greatest displacement of water (because of its large area) while requiring the least amount of armor (because of its shorter hull). This meant that the ship could carry larger and heavier guns while exposing only a sliver of its hull to direct fire at any point. Any shell striking the hull off its center would have the brunt of its impact deflected away. The flat bottom would ensure that the keel is not too deep in the water, allowing the ship to patrol the shallow waters of the Dniepr River and the Kerch Straits. It was perfect.
A model was built and tested on the Baltic Sea at St. Petersburg in 1870. The craft moved well and the test was deemed a success. When the results of the trial was reported to Tsar Alexander II, he ordered the circular ironclads be called “popovka”, a diminutive form of the designer's name.
A scale model of the Novgorod at the Internationales Maritimes Museum Hamburg. Photo credit: Zandcee/Wikimedia Commons
Popov and his assistants were soon busy working out various designs and dimensions. The General-Admiral wanted the biggest ship Popov could design with a diameter of 150 feet and displacement of 6,000 tons, but when the cost was worked out it exceeded the total budget of the entire program. Popov then designed a scaled down version, with a diameter of one hundred feet and displacement of 2,490 tons. The ship was armed with two 11-inch guns placed on a turntable at the center of the ship. Six steam engines each driving one propeller provided power to the ship, which gave her a modest speed of around 6.5 knots. She was named Novgorod and was launched in 1873.
The biggest problem with the hull’s circular shape was that it greatly reduced the rudder’s ability to turn the ship, requiring so much as 40 to 45 minutes to make one full circle. This made the ship almost unsteerable in a severe storm. The blunt hull also increased the drag, forcing the engines to consume prodigious amount of coal which gave her a range of only 480 nautical miles (890 km) at full speed. The problem with the rudder was solved by making the rudder fixed and using the propellers instead to turn the ship, at the cost of further reduction in speed.
The Novgorod's unusual hull gave rise to many myths, the most persisting one being that the ship tended to rotate about its axis uncontrollably whenever its guns were fired due to recoil making everyone on board giddy.
In reality, it was the ship’s lack of speed and maneuverability that saw Novgorod and her sister ship, the slightly larger Vitse-admiral Popov, relegated to the rank of floating forts to watch over the coasts. An attempt was made to sell them to Bulgaria, but when they turned it down, both ships were scrapped in 1911.
The Novgorod under construction. Image courtesy: John Jordan
The Novgorod a few days before her launch. Image courtesy: John Jordan
Comments
Post a Comment