V1.15 (2014/02/25) :

The reconnaissance (bomber) airplane now drops depth bombs, and has a gun for attacking submarines.
Each bomber can drop up to 8 depth bombs.
And a new fast airplane was added (fighter), it is launched by aircraft carriers and has a gun.
Each carrier have 37 fighters onboard, but controls only 5 fighters at time.
These airplanes can now attack your U-boat when it is at surface or when it is at periscope depth and the periscope is up !
They can attack your U-boat only during day time.

#) AA GUN:
A new AA gun has been added on the U-boat, for attacking airplanes, its button is near the standard gun button.
The standar gun has a reload time of 4 seconds, the AA gun has a reload time of 1 second.
Each gun can be used only when the U-boat is at surface.
Both u-boat guns cannon hit other units on the back of the submarine.

The radar ranges were reduced for all units (more realistic).
In the next updates some new options will be added to select more realistic (and difficult) sensor ranges and behaviour.

The rate of change of depth has been modified for U-boats:
When the submarine motors are off, the rate of change is now 0.1m/s.
(For example, for going from 50m to 100m depth, it takes 500 seconds).
When the submarine motors are on, there is an additional rate of change : (speed / 10) / s.
(For example, when the U-Boat travels at 8kn, for going from 50m to 100m depth, it takes about 60 seconds).
In practice, if you want to go up or down faster, power on your motors.

Max forward speed using diesel motors is still 18 kn.
Max forward speed using electric motors is still 8 kn.
Max backwards speed using diesel motors is now 12 kn.
Max backwards speed using electric motors is now 5 kn.

The rate of charge and discharge has been modified :

Batteries discharge when going forward with electric motors:
(Range) (Speed) (Duration)
320 nm @ 1 knt (320 h)
160 nm @ 2 knt (80 h)
107 nm @ 3 knt (36 h)
80 nm @ 4 knt (20 h)
43 nm @ 5 knt (8.7 h)
26 nm @ 6 knt (4.4 h)
17 nm @ 7 knt (2.5 h)
12 nm @ 8 knt (1.5 h)

Batteries discharge when going backwards with electric motors:
(Range) (Speed) (Duration)
125 nm @ -1 knt (125 h)
63 nm @ -2 knt (31 h)
30 nm @ -3 knt (10 h)
14 nm @ -4 knt (3.4 h)
7 nm @ -5 knt (1.5 h)

Batteries recharge (they are recharged only using diesel motors, at surface) :

If the submarine is at surface and stopped, batteries are fully recharged in 4 hours.
If the submarine is travelling forward with diesel motors at a speed minor than 12 kn, they are recharged in 8 hours.
If the submarine is travelling forward with diesel motors at a speed greater than 12 kn, the batteries are NOT recharged !
If the submarine is travelling backwards with diesel motors at a speed minor than 8 kn, they are recharged in 8 hours.
If the submarine is travelling backwards with diesel motors at a speed greater than 8 kn, the batteries are NOT recharged !

This is because the U-boat has 2 diesel motors, when it is stationary it uses both motors for batteries recharging, when it travels at low speed it use one motor for the propulsion and one motor for the battery recharging, when it travels at high speed it uses both motors for the propulsion.
Note: battery recharge is disabled in the Demo version.

Before the periscope depth was 20m, now it is 15m.
Hint: your U-boat can be detected by other units if it is at periscope depth and the periscope is up…
When I stay at periscope depth I keep the periscope always lowered, and when I need I raise it only for an instant, to avoid to be detected by other radars or sights.

Auto repair for airplanes is disabled.
Auto repair for ships is disabled when the ships are very damaged (when their health is below 25%), so if you cause a big damage to an enemy ship, you can wait and after some time the ship will sink (as in reality, so you can save some torpedoes).
And if a ship is damaged, it can auto repair only up to 75% (no more up to 100%).
IMPORTANT: if the health of your U-boat is below 25%, go at surface or after some time the U-boat will sink (auto repair works only at surface).
Note: the U-boat auto repair is not available in the demo version.

For the selected unit, a new information is shown : Allied, Enemy, Neutral or unknown.
And if the selected unit is out of your sensors range, all values are shown inside parenthesis, to indicate that these values could be inaccurate and not updated.
Important: the Health value is updated only when the selected unit is inside your sight range.

And BIG THANKS to Sergei G. for his useful hints and technical data !!!!!!!

V1.14 (2014/01/06) :

A reconnaissance airplane has been added, it is a four-engined bomber.
In future it will have bombs and guns, but for the moment it only flies and checks for other units with its radar, so if you meet it, it is safe to dive to not be detected and reported to enemies.

-) GUNS:
Now guns on different units have different ranges, and also some big merchants have guns and can defend !

Now it is possible to set the torpedoes course, from -180° to +180°.
To set their course, press 2 times the “torpedo launch window” button in the bottom of the screen and 4 new buttons will appear on the right, to increase or decrease the course offset.
When you launch a torpedo, it will run straight for 250m (0.135 NM) and then it will turn to the left or to the right, to follow the chosen course.
When a torpedo is launched it remembers its setting, so it is immediately possible to set a different course for the next torpedo without waiting.
Also the line on the map that shows the torpedo course has been modified, it is longer and straight or curved (it depends of the torpedo course offset), and it has more circles to indicate the torpedo provided position : 5 big circles every 1 minute (0.5 NM) and 22 little circles every 6 seconds (0.1 NM), for a better tracking.
The last little circle is at 2.7 NM, it shows the maximum range of torpedoes.
Very important : when launched the torpedoes are not immediately active, they will be activated after 250m (0.135 NM), this minimum distance is indicated with a red line, so if you want to launch a torpedo against a enemy ship, be careful to not wait too much or at the moment of the impact the torpedo will not be active and will not explode !
Important: now the torpedo tube reload time is 10 minutes (before it was 100 seconds).
Last thing, the probability for a war ship to detect torpedoes with its sonar has been decreased…

There are 2 new buttons to raise or lower the periscope, they are on the left of the “Change depth” window, and in the top of the screen there is also a little indication of its status (after the word “Depth”, a “P” or a “b” to indicate if it is up or down).
So if you are at periscope depth (20m) and the periscope is up, the other units have a little probability to detect you with radar or sight (for sight, only during day, not during night).
If at periscope depth you keep the periscope down, the other units can not detect you with radar or sight.
Note: it IS possible to launch torpedoes when the periscope is down !
Note: the periscope view is not yet available… I am creating 3D models for units, but I will need a lot of time to finish, probably months 🙁

Little improvement for realism, the other ships don’t detect your submarine if you are too near or below them.

The probability to detect other units (or your submarine) now depends on the orientation of the units: it is for simulating the different surface exposed to radio waves.
So if you are near an enemy and you point at it, you have a lower probability to be detected.

-) AI:
Now little warships ignore bigger warships.
And warships in convoys don’t ignore your submarine if you are at a distance less than 10 NM (before it was 5 NM), to better defend the merchants in convoys.

The sensors ranges of the selected unit are printed with the same colors as the circles on the map.
And the “Rel.Course” was renamed “Bearing”.

-) MAP:
If a unit has the same range for different sensors, the circles on the map are printed using arcs (it is easier to see when different sensors have the same range…).
A new red circle now shows the gun range.

V1.13 (2013/12/14) :

-) DECK GUN added to hit ships :
This gun is used to hit and sink ships, to preserve torpedoes.
It can be used only when the U-Boat is at surface, to use it go near a ship (no more than 1 miles), select the enemy ship and press the new gun button in the “Torpedoes Launch Window” (the same window you use to launch torpedoes).
The gun needs 4 seconds to reload and there are 250 munitions (use the Torpedoes Transport to refuel them).
Little hint: war ships also have a gun, but at night some of them (Frigates and Destroyers) have a visual range less than 1 mile, so if you stay at a distance of 0.8-0.9 NM you can hit them but they can not hit you !!

-) Submarine no more destroyed if batteries or fuel are at 0% :
With batteries at 0% now the U-Boat is not destroyed, and is possible to change depth; but without batteries the sonar, radar and hydrophones are no usable.
With fuel at 0% now the U-Boat is not destroyed, but it is not possible to move at surface or recharge the batteries.

-) Torpedoes damage doubled :
Now the torpedoes are more powerful, their damage is doubled.