Why can I not dive after an emergency blow?

[-Pv-]

When blowing ALL the compressed air you have stored forcing all the water out of the ballast tanks, diving immediately without charging means you have lost all the stored pressure necessary to bring you back to the surface using ballast tanks. Since there is no compressed air, you have also lost the ability to trim and control your depth. You can take on water to sink, but you cannot push it back out again. Planes and propulsion are not enough to compensate for the water you have taken on to dive. Your boat essentially becomes a rock with an engine.

If you are surfacing to save the crew with enemy nearby, then you blow emergency in order to abandon ship at the surface increasing your crew's ability to survive.

If you are blowing to get to the surface so you can make enough repairs to sail home (in the game, get to the map edge or abort the 3D sim) then there are no attacking enemy around and you have time to recharge.

Other than these two reasons, you should not be blowing emergency.
As stated above, you should only do this to save the crew and in most cases, you have probably lost the fight.
-Pv-

[Bungo_Pete]

I'm not saying flood the ballast tanks to bring the ship down fast just let in enough water for a slight down bubble(very slight negative buoyancy)
I am writing this after just getting racked by a kresta class cruiser his helicopter dropped a torpedo on me my skipjack dodged the torpedo with a blow and then he blasted me whilst I wallowed on the surface unable to dive
submarines have dive planes for a purpose.

[XenonSurf]

Oh, I just forgot to say: Going to flank and then putting the ballasts to +30 and also the planes at +30 will get you to surface quite as quickly. And also the contrary when on surface and you want to dive (-30 / -30), so no need to use the 'Blow Emergency tanks'.
In practise it's not that long: just steer a big angle with S and hit E multiple times to make the fastest possible surfacing. Then hit X to level.

[shipkiller1]

Originally Posted by -Pv-

When blowing ALL the compressed air you have stored forcing all the water out of the ballast tanks, diving immediately without charging means you have lost all the stored pressure necessary to bring you back to the surface using ballast tanks. Since there is no compressed air, you have also lost the ability to trim and control your depth. You can take on water to sink, but you cannot push it back out again. Planes and propulsion are not enough to compensate for the water you have taken on to dive. Your boat essentially becomes a rock with an engine.

Other than these two reasons, you should not be blowing emergency.
As stated above, you should only do this to save the crew and in most cases, you have probably lost the fight.
-Pv-

American SSN's do not use AIR to change the buoyancy (weight) of the ship. Using air is NOISY evolution in most circumstances and that's why is it not normally used. In the real world, after an EMBT blow and you wanted to re-submerge, you would just open the main ballast tank vents.

[The Bandit]

Originally Posted by shipkiller1

American SSN's do not use AIR to change the buoyancy (weight) of the ship. Using air is NOISY evolution in most circumstances and that's why is it not normally used. In the real world, after an EMBT blow and you wanted to re-submerge, you would just open the main ballast tank vents.

If a sub were to dive in this state (i.e. opening the vents to re-flood the tanks after the blow before recharging the compressed air tank) wouldn't that still be quite dangerous since the emergency blow system would be inoperative (little to no air) along with the torpedo tubes (assuming we're not talking about swim-out weapons)?

[shipkiller1]

Originally Posted by The Bandit

If a sub were to dive in this state (i.e. opening the vents to re-flood the tanks after the blow before recharging the compressed air tank) wouldn't that still be quite dangerous since the emergency blow system would be inoperative (little to no air) along with the torpedo tubes (assuming we're not talking about swim-out weapons)?

You are confusing peace time operational procedures with war time realities.

US Submarines do not use the EMBT blow system to routinely surface the ship. They drive to the surface and start the Low Pressure (LP) blower to blow the water out of the ballast tanks.
So, if in a war time scenario, you actuated the EMBT blow system, got the casualty under control, you can now re-submerge and start an air charge. You most likely will not 'blow until equalized'. You are going to have some air left in the tanks. Plus, unless absolutely necessary, you are not going to go back into battle.

You can also do the blow, decide that you do not need to surface and vent (open the MBT vents) on the way up.

With the air charge going, you are drawing air from the 'people tank' and when necessary, go to Periscope Depth (PD), raise the snorkel mast and 'equalize ship pressure', bringing vacuum down and putting a small pressure in the ship, and go deep again. We do this all the time.

You CANNOT pull air from the ballast tanks.

[Capt.Hunt]

it would be nice if the ships had a snorkel in game, for just that kind of event. Also, the ability to partial blow the MBT would be useful.

[ETR3(SS)]

Originally Posted by Capt.Hunt

Also, the ability to partial blow the MBT would be useful.

Useful how?

[shipkiller1]

Originally Posted by ETR3(SS)

Useful how?

Very useful during some operations.

Surfacing through the ice.
Jump 50

and so on...

The 637 class had a normal blow system which blew the MBT's from air bank five only.