The Reload Time of the 12.7 cm/40 Type 89 Naval Gun on the Yamato Battleship

The 12.7 cm/40 Type 89 naval gun, installed on the Yamato battleship, had a reload time of approximately 30 seconds per round. This impressive speed was relatively fast for naval guns of its caliber during that era, allowing for a decent rate of fire in combat situations. However, it is important to note that this gun is unfortunately no longer operational as it lies in deep waters, making it impossible to conduct a live reload demonstration.

Reloading the 12.7 cm/40 Type 89 on the Yamato

The 12.7 cm/40 Type 89 naval gun was a pivotal weapon in the Imperial Japanese Navy (IJN) arsenal. It was employed on a variety of ships, including destroyers and heavy warships early in World War II. The gun was designed with a dual-purpose capability, effective not only in anti-aircraft (AA) engagements but also in surface warfare.

During its operational lifespan, the 12.7 cm/40 Type 89 could achieve a relatively rapid firing rate, with an initial rate of fire of approximately 8-14 rounds per minute when ready rounds were available. This rate would decrease to a sustained rate of 8 rounds per minute after the ready rounds were expended. Given a full magazine, the practical firing cycle would be around 5 to 7 seconds.

Factors Influencing the Reload Time

Several factors can influence the actual reload time of the 12.7 cm/40 Type 89 naval gun:

Ammunition Supply: The rate of fire heavily depends on the availability of ready rounds. Once the ready supply is depleted, the gun relies on rounds from service magazines, which can slow down the firing rate. Crew Training and Experience: The speed of shell handling processes and the crew's training play a crucial role in achieving the optimal firing rate. Shell Hoists and Elevators: Changes in the speed of shell hoists and elevators can impact the time required to reload the gun.

Technical Specifications

According to naval records, the 12.7 cm/40 Type 89 had an initial rate of fire of 14 rounds per gun and a sustained rate of 8 rounds per minute. The ROF (Rate of Fire) is often given as a range, such as 14-8 Rounds per minute, with 8 being the sustained fire rate. In practice, this means the gun could fire 8 rounds per minute, assuming the supply of rounds in the service magazines is sufficient. This implies a reload time of approximately 4 seconds per round, given that the gun fires at 8 rounds per minute.

However, the 35 kg round was known to be quite heavy, making the physical task of reloading a daunting one for the crew. This aspect of the gun's operation underscores the importance of well-trained and experienced personnel to achieve and sustain the desired firing rate.

Replacement and Evolution of Naval Guns

By the later stages of World War II, the IJN had shifted to the 3.9 inch dual-purpose gun as a replacement for the 5-inch/40 Mark 89. This new gun offered superior performance and was used on both new destroyers and as secondary batteries on heavy warships. Despite its modest range, the 5-inch/40 had a practical firing cycle of 5-7 seconds, thanks to its handy mount design.

The twins of the 5-inch/40 were the primary anti-aircraft and secondary battery weapons on many Japanese ships, providing a crucial combination of firepower and flexibility.

In summary, the 12.7 cm/40 Type 89 naval gun on the Yamato battleship had a relatively fast reload time of around 30 seconds per round, making it a formidable weapon during its time. Although it is long decommissioned, the knowledge and techniques associated with operating such powerful naval guns remain a significant part of naval history.

Key Points:

The 12.7 cm/40 Type 89 had an initial rate of fire of 14-14 rounds per minute. Sustained fire rate was 8 rounds per minute after ready rounds were expended. Factors influencing the reload time include ammunition supply, crew training, and shell handling equipment. The 3.9 inch dual-purpose gun replaced the 5-inch/40 Mark 89 in the later stages of WWII.