Active sonar?

[lasertrout]

But submerged subs can attack any kind of boat they can see, right?

Sorry, just trying to make sure I've got this straight.
(I thought subs were only for nukes.)

[xyzyxx]

Subs in active sonar mode use Sonar pings to detect Carriers, Battleships, and other Subs. These vessels show up as white/grey sprites that fade away until pinged again. Your Subs can attack any Carriers, Battleships, or Subs you can see. If they're in Passive Sonar mode, they will not attack unless you command them to.

Sonar Pings appear on the other player's Radar, if the pings are within range.

[Mirray]

Submerged subs cannot be attacked by battleships or aircraft. Only carriers and other subs can attack them.

Here's to clarify.

Subs can use a conventional (and rather effective) attack versus all kinds of ships (battleships, carriers and subs) in either passive or active sonar mode.

In passive sonar mode, they are blind and rely on other ships (or aircraft) to guide in what they can shoot at.

In active sonar mode, subs ping out a sonar pulse to search for enemies both above and below the water (i.e. i will be able to see all kinds of ships). From my experience, they DO NOT surface as long as they attack ships with their conventional weaponry. The sonar pulse IS visible to all within radar range, but the ship itself is not. However, a smart player will realize that the sub pinging is not their own and will call in carriers/other subs to take out the enemy.

Basically, battleships can NEVER attack subs unless subs surface to MRBS mode (or are spotted by carriers, subs?).

In MRBS mode, subs surface and start launching nukes. As we all know from experience, they are most vulnerable at this stage and are targetable by all kinds of ships, aircraft and nukes.

When should I use???

Passive sonar mode: Getting your subs quietly to launch an enemy surprise attack. Keeping your subs stealthed while they attack the enemy ships (they will require radar assistance from above).

Active sonar mode: You used up all the missiles from your subs, now set them to active sonar mode and scour out for any leftover enemy subs or carriers that could launch nukes against you. You've found lots of vulnerable ships (battleships, carriers that have yet to be set to anti-sub mode), but have no radar units in the vicinity.

MRBS mode: To paint pretty pictures of NUCLEAR ARMAGEDDON on your enemy's nukes and cities! As a good tip, when all your subs in a fleet (I usually have them in fleets of two, but some enjoy a 6-pack), set one to MRBS mode. If the submarine does not immediately blow up, then you know they'll be safe from retribution from enemy boats / aircraft in the vicinity. Otherwise, pack up and hide for a while (or else you risk losing ALL your subs and their precious cargo).

EDIT: Doh... xyzyxx beat me to it.

[lasertrout]

Congratulations, sir, you have just written the bible of Defcon submarines!

Very useful, thanks.