[2023] The only way to deal with a sub is to turn and run as soon as you become aware of its presence

Can you post some Replays that demonstrate the situations you're in? It could be useful to examine.

Alright, I've reviewed both Replays. I can see that you felt pressured by the Sub's presence, but the external factors seemed to be the much bigger problem in both matches. I'll do a brief thing because I need to head to bed soon.

-

Match 1 (Zeiten):

The middle spawn looks to be headed to C. A will be light and C-flank will be the heavy flank.

Double DDs are pushing C cap for your team. They've encountered an enemy DD. Your Sub is exploring 9 line.

You've taken minimal damage while moving up. One of your DDs is dead and the other bailed on the Cap. Your Alabama is now pushing mid towards 2 BBs (potentially 3?) which seems sus. There are three enemies spotted south of C.

You just avoided a ping and some torps and throw some ASW at the ping marker. You now know a Sub exists. You are still northwest of C and in a covered position. The Baltimore and Mahan are leaving. There are 4 reds covering C cap.

At this point, you could attempt to do some ranged trading with a North Carolina/Schors, but you're in a Zeiten and it's early in the match. Your ship shines in the mid-late game when it's not overwhelmed by fire due to your lesser BB armor. Now would be a good time to either dig in (which means Schors HE and Sub torp spam) or bail. As you have literally no other ships to support any effort at C for the foreseeable future (eventually the 9/10 push might finish the flank and wrap C up), probably best to bail.

Note: The thread is about leaving because of Subs, but the bigger issue is "What can you accomplish here?" You don't want a 4 v 1 and you can't claim a cap since you'll be reset. There's nothing here for you until you have teammates to make plays off of.

You juke some torps and shove in. You take damage. Now you're pinched between two BBs, which is scary in a lighter-armored BB like the Schlieffen-line BBs. You might nab the Schors but this is over-committed and there's no way out.

Within a few more seconds, you are sunk.

The Submarine's line of fire/threat did spook you into charging forward to avoid sub damage, but you sailed into death. From your position there were 3 BBs that could shoot you, and a Schors (nearly dead), eventually a CV if the Alabama is sunk or the CV detours a bit to work on you, AND a sub. There's just no way you win that fight.

Ideally, you'd have one of your DDs between you and the C cap which would screen incoming torps/pings and allow you spotting for ranged fire. Schlieffen line has comfortable guns that can work at range until you find a good time to press the attack with secondaries flaring. Instead, the loss a DD early spooked your teammates and you hit to Go Button a bit early.

Match #2 (Baltimore)

This match was pretty straightforward, actually. I feel you got stuck because US Cruisers love islands and the enemy's mid spawn flooded A.

-

1.5 minutes into the match, you see both enemy mid-BBs heading A-flank due to CV spotting. Your spawns' counterparts haven't been spotted yet, but fair chance they head to A since they spawned at A.

Note: The enemy team has 4 BBs and yours has 3. It looks like this is a queue-dump that made stuff fit because of Divisions. It's likely you have 3 enemy BBs at A while you have 1 (the mid BB and Cruiser on your side are heading D).

More information comes in. You have 1 sub (probably mirrored on the other side by a sub, though Divs can make stuff weird), a DD coming from mid, a single BB and a single CA. Enemy shows 3 BBs, 1 CA, probably a Sub?

You've hard committed to the island near A, but with the much firepower how are you going to stop them from walking over your flank? If you decide to run, how do you run away after taking such a forward position?

Subs spot each other. Some blind torps are chucked toward you (you weren't pinged). You reach the island.

The enemy North Carolina is also there. Enemy is now 4 BBs, 1 CA, 1 Sub vs 1 BB, 1 CA, 1 DD, 1 Sub. 6 v 4 is rough, and BBs vs Baltimore armor is scary. Staying is death and the sub does have an angle on you to throw torps so there's feeling of a time-limit on cover and a time-limit on enemy push killing you anyway.

Harbin spotted too in the north. 7 v 4. Omaha has you on Hydro and yolos. Doesn't use torps for some reason, but generously gives you citadel candy to eat.

After killing the Omaha, you see submarine torpedos. You turn to the Right instead of continuing to run away from 4 Battleships that will overtake your position.

You should have considered using DCP to clear the ping if the torpedoes were very scary. They are very scary because you are double-pinged (39 seconds indicates longer, stronger ping) and double-pings are MUCH more accurate then single pings. By having some angle to mis-lead the torps, you can DCP and turn in a little when they are close enough that they will pass before you can be pinged again.

South was required because 4 BB. Turning North is death.

Sub torps landed (double-pings are scary) and BB shells too. With the North Carolina shoving A there is no out.

Battleship shells finish the job.

-

Taking the island left-of-cap would be great if your flank was evenly matched or to your advantage. Unfortunately, it was not. CV spotting did give you some warning when it noticed the two BBs heading to A, but the other two BBs also being in a Div and also spawning above A meant there was no way back from such a forward position.

The island at G2 would be been more conservative until you have more intel from your Sub or the two CVs would of planes in the air (1 T6 and 1 T8 CV on each team). That might have afforded you some room to run, though you still would have been running away in front of 4 BBs in a cruiser coated in 27mm.