Tower bridge was the ship's control center. Perched at its top, 100 feet (30 meters) above the weather deck, was a rangefinder with state-of-the-art optics. Similiar rangefinders aided targeting at Yamato's three main gun turrets. Their range estimation would have been critical in battles with distant enemy ships. But like Yamato's modern radar and sonar equipment, the rangefinders were little or no help in her final showdown with Allied planes. Yamato veteran Naoyoshi Ishida, who was stationed at the tower bridge, could see the American pilots with his unaided eyes!
Tower bridge illustration
Tower bridge as seen in the model in the Yamato Museum at Kure, Japan.
This was Yamato's weakest point compared to its Allied counterships. Yamato was using Mk2 Mod2 gun-control radar with a wavelength of 10cm and power output of 2kW, compared to for example USS Iowa which had 3cm wavelength and 50 kW power output. According to Combinedfleet, Yamato was cabable of shooting accurately to 27.000 yards. Yamato was relying on the information carried from the spotplanes, but was not able to take advantage of the full blind-fire radar fire control, something that the Americans had developed a bit further. Therefore during fast manouvers such as dodging torpedoes, keeping accurate fire up against the enemy targets wasn't easy.
- Two Type 21, Mod 3 surface and air search radar. One mounted on
either side of the 15 meter rangefinder.
- Two Type 22, Mod 4 Surface search and gunnery radars
(10cm at 1 Kw). One mounted on either side of the main control tower. (little horns)
- Two Type 13 air search sets (mounted on either side of her radio-spreader mast aft of the main funnel)
- Multiple E27 passive radar detection systems (copied German FuMB 1 Metox R.600)
Although Japanese radar does not compare well with Allied sets of the same period, which were capable of full blindfire without optics, she was not blind either by any measure.
Japanese radar was reliable and durable, withstood shock well, mostly because it was cruder, lower power and lacked as many sensitive advanced parts that superior Allied radar had.
Her radar assisted (not controlled) the finest optical fire control system mounted afloat in WW2, which also had the best night fighting sets. She had both a special analogue computer and electronic firing delay between guns to lesson dispertion and tighten her salvo speads. The whole strategy was to land a tight, massive impact of Type 91 shells just shy of the waterline, to drive the shells through the water and deep into the hull.
Main battery fire control was exercised by the Type 98 LA system with a director position atop the foretower with a 49ft range-finder and a secondary position aft fitted with a 33ft range-finder. All three 18in turrets also carried 49ft range-finders. Secondary battery control was by means of four directors each equipped with 15ft range-finders, while the 5in AA battery was controlled by the Type 94 HA system, which was reputed to compare very favourably with the USN's Mk 37 DP system.
A golden, chrysanthemum-shaped shield more than six feet (two meters) in diameter protruded from ship's bow and was visible for miles. Such "Kikusui" crests, named for a hero and martyr on the 14th century, appeared on only the most important ships of the Imperial Navy - battleships, aircraft carriers, and cruisers. The only other element that was painted gold was the ship's name, which like the crest was apowerful symbol. "Yamato" is a poetic, even mystical synonym for Japan itself.
Illustration of the chrysanthemum crest
The chrysanthemum crest as seen in the Yamato model built for the movie Otokotachi no Yamato.
Yamato had 1150 watertight compartments, which were meant not only to prevent unwanted flooding but, in some cases, to purposely be flooded. If the ship listed to one side, water could be pumped into compartments on the opposite side. Fuel could also be transferred to tanks on the upward side to help counter the tilt. Midway through Yamato's last battle (see Battles), as the ship listed 15 degrees to port, her crew relied on the system to reduce the tilt to five degrees. But soon all the flood control departments on the starboard were filled, and more torpedo hits flooding on the port side capsized the ship.
The ship's steel armor weighed 23.000 tons, more than 30 percent of Yamato's total weight. The Imperial Navy developed new ways to harden steel and otherwise improve armor technology for the ship. Plated of armor 25 inches (63cm) thick - the heaviest armor ever mounted on a battleship - shielded the turrets of her main guns. The side of the ship could survive the impact of 3000-pound armor piercing projectiles like those shot from the ship's big guns. But Yamato's bow and stern were not as well protected. Most of the torpedoes that ultimately sank her struck there, below the waterline, where she was most vulnerable.
If greatness can be measured by size, Yamato was indeed the greatest battleship ever built. Her giant hull was 863 feet (263 meters) long. Fully loaded Yamato diplaced about 70.000 tons of water, outweighting even the biggest Allied battleships by more than 20 percent. Her hull was so immense that in the mid-1930s no Japanese shipyard could contain it. A dry dock in Kure, the city where Yamato was built, had to be deepened by several feet before construction could begin.
Yamato's vast width posed a challange: her designers had to come up with a hydrodynamic bow to help the ship cut through water. They tested 50 different wax models and struck upon a bow shape that greatly reduced drag at the front of the ship. The bulbous bow, jutting out 10 feet or three meters, creates its own wave that cancels out another wave generated by the main part of the ship. Less hindered by wave resistance, Yamato could reach top speed of nearly 28 knots, 32 miles or 50 kilometers per hour, extraordinary at the time for a ship of her size.
A system of four steam turbine engines with a staggering 150.000 horsepower propelled the massive ship. Twelwe boilers, heating steam to 700 degrees F or 370 degrees celcius, fed the four engines which then moved an array of propellers. Each propeller was nearly three times the size of an avarage man! At Yamato's maximum speed of 32 mph or 50 kmh the propulsion system consumed 70 tons of fuel oil every hour. Thats equal to 440 barrels an oil in an hour, 33.000 US dollars in an hour with todays oil prices!