Effects of the switches.
The following is only a brief summary. Full details of each H.sie fix can be found in the documentation for the SH3 patch that you have applied.

Realistic Repair Times (V15A or later)
Repair times of all U-boat equipment (periscopes, engines, pumps, sonar) take 60 times longer than before. An 1 minute repair in Stock SH3 now takes about 1 hour instead. The repair time estimations are displayed in 1 hour steps. The flooding behaviour (flooding-times, recovery) is not changed! So you still have these dramatic minutes fighting against the flooding water. The repair times of the compartments are also not changed, since they are directly linked to the flooding recovery.
Not recommended for users of NYGM. (Switch should be OFF.) Also do not use either the older LRT (Longer Repair Times) or the LLRT (Little Longer Repair Times) mod.

Inaccurate range-estimations (V15B or later)
Inaccurate range estimations for Watch Officer (->Nearest visual contact) and Weapons Officer (-> Solution to target). No gods-eye firing-solutions anymore. Before this mod: “Range: 8932m, Herr Kaleun”. Now: “Range: 9000m, Herr Kaleun”. The range estimations now are displayed (and used internally for firing solution) in certain range-steps, which become larger (more inaccurate) for larger ranges. In detail:
* Range 0000-1000m: Steps: 50m (Weapon Officer) 100m (Watch Officer)
* Range 1000-2000m: Steps: 100m
* Range 2000-4000m: Steps: 200m
* Range 4000-9000m: Steps: 500m
* Range 9000-12000m: Steps: 1000m
* Range > 12000m: Steps: 2000m


Snorkel-Fix (V15D or later)
Speed restriction when snorkelling - wind speed dependent! (Speed restriction starts 20 seconds after beginning of snorkelling. This was necessary to prevent that speed restriction handicaps crash dive).
* Wind speed = 0...5m/s: Uboat speed restricted to “1/3”
* Wind speed = 6...10m/s: Uboat speed restricted to “slow”.
* Wind speed = 11...15ms/s: Uboat stopped. Snorkelling impossible.


Periscope-Fix (V15D or later)
Restricted Periscope usage for higher speeds
* For speed > 4,5kts Blur effect simulates vibrations. Periscopes nearly useless.
* For speed > 7kts periscopes are moved down automatically.
If the underwater speed exceeds 5 kts, the periscope may be forcibly retracted, or you may see periscope tremor instead (depending on whether the additional graphics file is added too).

Hydrophone-Fix (V15D or later, bugfix in V15F)
Hydrophones useless when diesels are working.
* When snorkelling, you must stop diesels in order to use hydrophones. Otherwise you’ll hear nothing.
* No sound contact reports when diesels are working.
The hydrophone operator cannot hear anything when the diesel engines are employed, above water or below it (with schnorchel).

“Crash dive blues” - Bug fix by H.sie and Stiebler (V15E or later)
From now on, you don’t lose control over the sub anymore if you interrupt a crash dive before the sub has reached its designated crash dive depth. NYGM players will benefit especially from this fix, since in NYGM the Crash dive blues is more noticable.
Prevents the old problem that an interrupted crash-dive (for example, by setting a greater depth before the crash-dive is completed) will cause the U-boat to settle out at the new depth at an angle, and become difficult to control at slow speeds.

Fog warning - by Stiebler (idea) and H.sie (programming)(V15E or later, enhancements in V15F and V15G)
During high time compression (TC) it can happen that suddenly heavy fog occurs, but the player doesn’t notice it and therefore will not be able to act according to the new situation. This fix reduces TC>16 to TC=16 whenever fog occurs in order to warn the player. In V15F and later, Fog warning is only active when the boat is not submerged deeper than periscope depth. Additionally, the watch officer reports “fog sighted”. In V15G he also reports if fog disappears.

External torpedo reload fix (V15E or later, enhancement in V15F)
* No reload of external torpedoes possible during bad weather (=storm conditions defined in .cfg file of the sub). If bad weather suddenly occurs during external reload, the torpedo will be considered as reloaded if more than 75% of the reloading work is done, otherwise the torpedo will be put back to its initial position, but the reloading process will be automatically restarted when bad weather ends. * Speed restriction to “slow” during external reload. * No diving possible during reload of external torpedoes, since all diving commands are simply ignored. If an enemy is sighted, the first pressing of the ‘C’ key (crash dive) is now interpreted by the game as “ALARM!! Interrupt reloading!!! We must dive!!”. After that Alarm, the LI tells the kaleun, how many minutes it will take to interrupt the reloading process. During this time, the boat still cannot dive. (The time necessary to interrupt the reloading process is randomly chosen between 4 and 13 minutes). Reloading of torpedoes (internal, external) is only permitted when conditions are right (nearly flat seas for external torpedoes, sufficient depth for internal torpedoes).

Internal torpedo reload fix (V15E or later, enhancement in V15F)
No reload of internal torpedoes during storm and when surfaced. During storm one has to dive below 30m in order to reload internal torpedoes.

Watch Officer automatically moves to bridge when surfacing (V15E or later)
The lazy watch officer now moves automatically to the bridge when surfacing. If there is an Officer in the Bow-Quarters he will move to the bridge. If not, an Officer from the Stern-Quarters will be moved up. If the Turm is critically damaged or destroyed, no Officer will be moved up.

Oxygen-Supply - by LGN1 (idea) and H.sie (programming) (V15F or later)
With this fix, O2 is divided into two parts: A renewable part and a non-renewable part.
The renewable part is the O2 in the air of the Uboat. This part is sufficient for a diving period of about 5-7 hours. During this time the LI informs you about the O2 content of the air, starting at the normal value 21% and slowly decreasing to the critical value of 17%. At 17%, the LI automatically starts to add O2 from the oxygen-supply (contained in pressure bottles).
The bottled O2 supply is sufficient for a long diving period of about 30 - 100 hours (depending on U-boat type), but that O2-supply is non-renewable! That means: It is not filled up when surfacing. Only the O2 in the air is restored to the normal value of 21% when surfacing. The former CO2-Gauge now acts as a gauge for the non-renewable O2-supply.
The two sliders at the bottom of the Options Selector allow the default oxygen supplies to be varied (default = 1.0 for renewable and non-renewable supplies.)
Further details in Oxygen Supply.

WarNews - by Stiebler (programming) and h.sie (code reworking) (V15G or later)
Prevents the irrititating drop in time compression (TC) to TC=1 every time a piece of war news is transmitted to your U-boat. (E.g. ‘The port of Riga is in our hands again.’)

BDU-Messages Mod (V15G or later)
This is an enhancement of Stiebler’s BDU-congratulations mod. Instead of the monotonic 2-3 standard BDU responses to status reports, there are now 28 different messages from BDU, depending on your tonnage sunk, fuel supply, hull damage, remaining torpedoes. Provides a varied range of responses when you sent a status report to BdU, see Status reports and replies from BdU.

U-tanker Fix
Now you dock properly at a U-tanker, instead of starting a new career.See U-tankers.

Radar Fix (V15G or later)
Radar automatically switches back to ON state, when it has been switched OFF in high waves. Additionally, now the default state is OFF when a game is loaded.

Wolf-pack Mod - by H.sie (programming) and LGN1 (idea) (V16A or later)
You have now the option to call-in a wolf-pack to help you with your attack!
The idea is that, when you locate a convoy, you send Convoy Contact reports by radio every hour or so, until a wolf-pack is ready to attack. Then, once night-time falls, BdU will tell you:
Either to attack alone (wolf-pack could not be assembled in time; perhaps due to bad weather or an insufficiency of contact reports;
Or that the wolf-pack is about to start the attack.
If the pack attacks, you may well see realistic torpedo strikes on merchant ships, and a map-view will show some of the ships of the convoy sinking.
For full details about how to manage the wolf-pack attack, see: Wolf-packs.

The Stiebler Selection.
These further options can be installed with a separate patch from Stiebler.
Silent-Running Fix - by Stiebler
Will cause the U-boat to sink very slowly when silent-running at slow speed (<2 kts). In particular, an attempt to come to the surface under these conditions may cause the U-boat to sink instead as the hydroplanes turn to a steeper angle and lose their buoyancy. See Silent Running.

Surrender Option - by Stiebler. Red radio icon made by SquareSteelBar
You can surrender your U-boat when the damage is too severe, with hope of continuing your career with a new boat after being rescued by a U-boat.
1. Click on the Radio Option marked “Surrender U-boat”.
2. Then send a radio status report to BdU (click on radio status). This sets an explosive charge in the U-boat, to detonate after 10 minutes.
3. Then self-sink (scuttle) the U-boat, even in shallow water.
4. If you are rescued by a U-boat, you can continue your career. Otherwise, your career is ended.
See Surrender/Abandon ship.

“Smoke on Horizon” mod - by Stiebler
Recapture that moment of magic from the old ‘Aces of the Deep’ U-boat simulation, as your crew shout out “Smoke on the Horizon, Sir!” when they detect a convoy.
See Smoke on Horizon!.

CAM-ship - by Stiebler
Restricts the number of times that an aircraft will be flown off from a Catapault-Merchant-Ship (CAM-ship). Only one aircraft will be allowed during any one patrol. Requires installation and correct configuration of one of IABL’s CAM-ships (Ship M36B is well known, also M21B).
See CAM-ship.

Asdic in shallow waters - by Stiebler
Causes the asdic underwater location device used by warships to become less effective in shallow waters.
See Asdic.

Warning Dialog Box - by Stiebler
Prevents the irritating drop in Time Compression to 1 every time that an enemy destroyer comes out of the mist, which causes the warning dialog box “WARSHIP SPOTTED” to appear.
See Warning Dialog Box.

Minimum TC - by Stiebler
Sets a minimum value for time compression (default = 128) below which no game event (or the user!) can reduce time compression.
Useful when tailing convoys, sailing out from narrow waterways or in the Kiel canal, or raising the U-boat away from the sea-bed; dangerous at other times, see Minimum TC mod.

Change Patrol Grid - by Stiebler
Allows a single request for a new patrol grid, after you have explored the original patrol grid.
Subject to conditions, see Change Patrol Grid mod.

Null Grid Fix - by Stiebler
Creates a new patrol grid when previously you would have received a NULL grid, for example when sailing from a port which is not your home base.
See Null Grid Fix.

Weather Meter - by Stiebler. New weather icon by SquareSteelBar
Changes the Stealth Meter (which shows whether a U-boat has been detected) to a weather meter (shows current visibility).
This is useful when patrolling at sea, but only for those who play the game realistically and therefore do not need the Stealth Meter. See Weather Meter mod.

Ship Speed Fix - by Stiebler. Idea by Hitman.
This fix reduces ship speed according to wind-speeds.
It is not correct that the U-boat’s speed should be reduced (in the original devs’ code) when trying to escape on the surface during a storm, yet the pursuing escort’s speed remains at a maximum. The mod reduces all ship speeds by a factor that depends on the wind speed, but is independent of the direction of the wind. This is fair, since the U-boat’s speed as originally programmed is affected only by the size of the waves/wind, not by their direction. The U-boat’s speed is not affected by this mod.
The mod is found exclusively in the SH3Sim.act file provided with the Stiebler patch, which replaces the original file, and therefore there is no toggle for the mod in the Options Selector. If you don’t want it, restore H.sie’s original SH3Sim.act file. There is no toggle for this option in the Options Selector.
IMPORTANT: This file replaces H.sie’s original SH3Sim.act file. It will cause a Crash-to-Desktop (CTD) if used to replace any other SH3Sim.act file (including that provided with stock SH3.exe.)

Air Torpedo (FIDO) mod - by Stiebler.
The Air Torpedo mod simulates the dropping of an Allied acoustic torpedo (FIDO) from an aircraft onto your U-boat when it is submerged. It is deployed only from 1 July 1943 in this mod, and the air torpedo can be evaded simply by reducing speed to the lowest speed possible. However, a torpedo hit will cause very serious damage - often fatal. See Air Torpedo (FIDO) mod.

Radar-Turm fix - by Stiebler. Turms and rotations by Anvart.
Ensures that the fixed (FuMO29) and rotating (FuMO30/61) radars are installed in the correct places on the conning tower. See Radar-Turm Fix.

** Not Used **
These switches at present serve no purpose, and can be ON or OFF without effect.