- Destroy the two specified cargo ships
- Sink all escorting warships
- Sink all the cargo ships
This mission is easy to win at, but difficult to fully beat. Despite the fact that you have over 30 torpedoes, even if you have 100% accuracy with all your torpedoes you cannot sink the entire convoy, the two cruisers, and the two escorting destroyers with all of them.
The challenge is made even more complicated by the presence of PT boats, which are too shallow for you to torpedo. When surfaced they can hit you with their main cannon, and while submerged they can hit you with depth charges.
Approaching the Convoy
The ships you have to sink are different every time, but fortunately even your submarine can outrun them, so they should be a no-factor. What should be on the forefront of everyone's mind is the destroyer - the Yuguri - which quickly approaches you to try and hit you with depth charges. Perform the head-on attack against it (this is the best place to practice the head-on attack) to sink the warship. Otherwise crash-dive to depth level 4 and try smacking it with your rear torpedo tubes if you can (doing so entails a LOT of damage from the destroyer's depth charges)
Once the destroyer is dealt with, raise your periscope and look around. The computer will notify you once you've spotted a mission critical target and it will remain under a gold objective bracket for the duration of the mission.
Once you're in position, fall in trail with the Mikuma, the heavy cruiser. Send four torpedoes into it in order to send it to the bottom.
Sailing along the port side of the convoy is the light cruiser Kitakami. It takes about three or four torpedo hits to sink the Kitakami, the light cruiser. Once that's done all that's left is for you to torpedo the Asagiri (assuming you haven't shot it already with your rear torpedo tubes) and you've sunk all the Japanese military units - except the PT boats. While it is possible to surface and remove the enemy PTs with your deck gun, it is not recommended - the Japanese model have artillery pieces that can strike a surfaced submarine down quickly.
Use your minimap to track the movement of enemies, especially the PT boats. Your radar is of limited use, since it does not distinguish between troop transports, enemy warships, or PT boats.
Some players have noted the appearance of three depth charge-equipped F1M Petes upon the elimination of all enemy warships (The Yuguri, Asagiri, Kitakami, Mikuma, and the 2 PT boats), but others have noted they do not appear. In the event F1M Petes do appear, try to be at the midway point between depths 3 and 4 to try and get them to lose their ammo.
Blasting and Diving
The trick is to be patient and to use depth level 4 liberally. If there is any remote sign of a unit (especially a PT) coming to depth charge you, crash to depth level 4 regardless of circumstances.
One trick that has been observed is that, from crush depth, the submarine rises extremely slowly to torpedo depth. However, if you order the sub to surface instead, you will rise much faster. When at crush depth, try ordering your sub to the surface, then order torpedo depth once you're already at it. You'll have a much easier time torpedoing at close range - and staying at crush depth for longer periods.
Do not even consider surfacing for air until all of the following criteria have been fulfilled:
- The two cruisers - the Mikuma and the Kitakami - have been sunk.
- The two destroyers - the Yuguri and the Asagiri - have been sunk.
- The two troop transports (see right) have been sunk.
- The Gyoraitei PT boats no closer than 0.7 nautical miles (or, about 3/4 of the radius of your sonar).
The mission ends when the two cargo ships are sunk, but if you want the secret objective, you have to sink the whole convoy. Unfortunately, you don't have enough torpedoes to sink everything. Unfortunately, therefore, you must rely on your deck gun. Aim for the cargo containers and do your best to arc shots on top of them to send them to the bottom. Your machine gun can try and take potshots against the enemy PT boats, but be wary of their artillery.
Once you've removed both critical cargo ships, the mission is complete.