Surveillance submarine I-501
Surveillance submarine I-501 with her equipment exposed
Japanese Name: イ-501
First appearance:
Manga: Chapter 2
Anime: Episode 2
Vessel's status:
Affiliation "Fleet of Fog",
First Oriental Fleet
Status sunk
Sunk by I-401
General information:
Type "Fleet of Fog" Type IXD2 submarine
Displacement 1616/1804 tons
Length 87.6 m
Beam 7.5 m
Draft 5.4 m
Maximal Speed Unknown
Armament Unknown
Wave-Force Armor yes
Mental Model n/a

I-501 was a "Fleet of Fog" surveillance submarine paired with heavy cruiser Takao for a patrol mission. I-501 was destroyed by I-401 with a Super-Graviton Cannon.

I-501 submarineEdit

I-501 is a "Fleet of Fog" reincarnation of WWII Japanese submarine I-501 (originally, German Type IXD2 U-181 submarine). It is a relatively small and very slick submarine, who served as a surveillance submarine within the "Fleet of Fog". Because of this, it has very little in terms of firepower and has to rely on bigger vessels for protection.

While it is indeed not suited for a fight, I-501 possesses some high-quality sensors that may even come close to those installed on superbattleship Yamato's personal guards I-400 and I-402. I-501 was able to detect and correctly distinguish I-401 from her active decoys even in a heavy storm. In addition to this, she was able to land a hit on  I-401 beyond the range of even a battleship. 

I-501 has a moderately-powerful Wave-Force armor, but it was not powerful enough to protect her from a hit from a Super-Graviton Cannon.

I-501 surveillance submarine has no known Mental Model. If she had one, this Mental Model never made her appearance in the series.


On her last mission, I-501 was paired with heavy cruiser Takao as they patrolled the waters some hundreds miles to the south-west from Yokosuka port. In this part I-501 acted as Takao's eyes and ears while Takao herself would be the one to deal with any trespassers they found. I-401 turned out to be that trespasser.

As I-501 was hiding right underneath Takao, the crew of I-401 originally believed that they had severely underestimated the detection abilities of "Fog" heavy cruisers: Takao had almost sniped them with her Super-Graviton Cannon even though they were supposedly outside of her detection range.

However, once it was established the Takao didn't use her active sonar even once, they came to a conclusion that there was another vessel. And since they themselves couldn't see it anywhere near Takao, they (correctly) guessed that it was a small submarine hiding right underneath the heavy cruiser - the fact that Takao was moving much slower than her specs allowed her to was a further proof of this theory.

Deciding to break through with a fight, I-401 distracted Takao with a barrage of torpedoes before using her Super-Graviton Cannon. However, instead of shooting down the heavy cruiser, Gunzou Chihaya chose I-501 as his target. The shot destroyed I-501 and partially ensured the success of the bluff Gunzou used in order to get past Takao.