Evasion

• You can get an idea of how far away an escort is by listening to its pings. Escorts that are less than 4500 yards away have a sharper sounding ping than those that are more than 4500 yards away. The escorts' sonar seems to be able to pick you up only when you're within 3500-4000 yards. Consequently, if you're sneaking away from several escorts and some have sharp pings and some have fuzzy pings, you can ignore the escorts with fuzzy pings, i.e., keep a small profile to only the escorts with sharp pings. The escorts with fuzzy pings are too far away to detect you.

• At periscope depth with the periscope down, ships passing overhead will sometimes wreck your periscope. It's better to go down another 20 feet while the ship passes over and then come back to periscope depth than to take a chance on destroying your periscope. This can happen while working your way inside a convoy's escort screen, inside the convoy during the mad scramble after you sink a ship, or if you stay at periscope depth while evading the escorts. The hardest time to avoid this is while maneuvering around a harbor during a photo recon, because you'll have no sonar info on the ships at anchor and won't know when they're overhead if it's been awhile since you've looked around with the periscope.

• On a related note, destroyers have a hard time depth charging you if you are directly underneath a ship. I don't know if it's because they're smart enough not to drop DC's close to one of their own because it could be damaged or because they can't make a proper run on their sonar contact with the ship in the way. I hid underneath a heavy cruiser in Truk Harbor all day after a photo recon. When the destroyers gave up on me, I snuck out from underneath the cruiser, sank a juicy target nearby, then hide underneath the cruiser again. In between sinkings, I put the TDC in manual mode to keep track of the location of the cruiser while I was under it. I've used this several times since then.

• Gone as deep as you can and can't find a thermal gradient to hide under? You might want to think about returning to periscope depth, so that you can see what the escorts are doing. (I find this especially true when playing at 115% realism.) Listen to the amount of time between when the depth charges splash and when they explode. A long time means the DC's are going deep before exploding, so you might as well be shallow. If you can keep the escorts from spotting your periscope, they might keep thinking you're deep.

• You can sometimes mislead escorts by having a torpedo explode away from where you are. Torpedoes explode when they have travelled their maximum distance. The escorts will investigate the explosion, which can buy you time to get away. I found this out accidentally when trying to sink an escort (one of 8) with a small angle-on-the-bow shot. The torpedo missed, travelled its 3500 yards, and exploded. All of the escorts went chasing after it at high speed. I took off in the other direction and escaped. I've only used this with Mark 18's, so I'm not sure if it will work with the Mark 14's, since the escorts may see the wake and know where it was launched from. It does cost you a torpedo, but if you don't have enough torpedoes to get away from the escorts, or if you can't go deep because of damage or shallow waters, this can be a good option.

• If you're evading on the surface, keep in mind that you can do a much better job of aiming your deck gun than the computer can, especially if the sea is rough or you're turning. I put the deck gun on "auto" for a second to let the computer find the target for me. (Make sure it picks the target you want, if there's more than one nearby.) Then I switch to manual and select the target to do the shooting myself. For whatever reason, the Japanese destroyers don't usually shoot at you unless the range is less than 2000 yards. (This is not always true. I've been shelled at up to 5000 yards. I think it depends on the quality of the destroyer's crew.) I can usually hit destroyers at a range of at least 4000 yards in moderate seas. If two destroyers are chasing me with one nearly behind the other, I aim for the nearest one, hit him several times to slow him down, and then change course such that the undamaged destroyer has to go around the damaged one. Usually the undamaged destroyer slows down while going around the damaged one, so I can open up the distance and get away.

• Beware of the depths on the nautical charts. Several times I've been in locations where the chart shows water deeper than my test depth, only to run aground on my way down. (The dark blue area southwest of Manila comes to mind...only some of it is greater than 200 feet deep.) If you have time, submerge ahead of time in questionable areas to find out if the water is shallow. If you're caught in shallow water and have to evade, pay attention to your speed gauge: It will drop suddenly to 0 a few seconds before the sub runs aground, which can give you a chance to react. Also, you'll run aground sooner if you have a down angle than if you're level. Of course, if you play with the "depth under keel" gauge, you don't have to worry about the charts.

• If you've taken pressure hull damage, flooding seems to get worse as you go deeper. So stay as shallow as you can if you're having trouble with flooding.

• The test depth of the subs is conservative by about 50%. I've taken an undamaged Balao class sub (test depth of 400 ft.) to 627 feet before being crushed and an undamaged Gato class (test depth of 300 ft.) to about 460 feet. I don't know how much this varies from ship to ship. Note that in order to go below 600 feet, you have to control the dive manually. The depth gauge won't let you set the depth below 600. Don't let the sub get too steep a down angle or else you won't be able to level off before being crushed. To tell how deep you are when below 600 feet, you have to go to the chart screen and put the cursor over the sub.

• Evading subs: If an enemy sub launches a torpedo at you, go to flank speed and turn toward the torpedo so that your course is parallel to the torpedo track. Turning toward allows you to bring your forward tubes to bear on the enemy sub, and takes you closer to it for a counterattack.

Patrolling

• For guesstimating distances and intercept courses, I drew a set of concentric circles (You can also download it as a JPG if your system doesn't like postscript...I'll try to make this file smaller. It's 52K now) with markings every 15 degrees in my favorite drawing program, printed it out and photocopied it onto a transparency. You can lay this over the chart screen to estimate where a convoy will be in a few hours and to plot an intercept course. It works best if you make the largest concentric circle equal to the length of the scale on the waypoint tool.

• O'Kane said (in Wahoo, I think) that putting the target at 90 or 270 degrees relative will guarantee interception if interception is possible. I use this only rarely, but it comes in handy when I get a long range radar contact without any course information from the game. This is called the normal approach course. (Normal here refers to the angle between your course and the target's bearing being 90 degrees.)

• The information box that pops up on the map screen when you put your mouse over a convoy gives different information based upon how zoomed in you are. If you are at the strategic level (25, 50, and 100 miles on the scale), the dialog box gives the convoy's course. If you are on the tactical level (scale less than 25 miles), the dialog box gives the convoy's bearing. (Note that a convoy has to be sighted for it to show up on the tactical level.) The course is the compass direction the convoy is moving in; the bearing is the angle between the front of your sub and a line drawn from the center of your sub to the convoy.

• As you are patrolling, watch the contact reports to find out the most heavily travelled routes. Try to place yourself where two or more routes come together. You should also pay attention to whether the convoys are merchants or capital ships. Some routes seem to be more heavily used by one or the other. If you're running low on torpedoes, you might not want to be on a route which is mostly used by capital ships, as they require more torpedoes to sink and tend to have more escorts.

• If the seas are moderate or heavy, your sub will lose speed on the surface and submerged down to about 100 feet. Below 100 feet, the state of the sea no longer affects your speed. There's a small difference in speed between radar depth and periscope depth, and larger difference between periscope depth and 100 feet. The extra speed can have a major impact in the distance you travel between recharges while patrolling, and how close you can approach a ship's track submerged.

Torpedoes, Radar, and TDC

• Dud torpedoes can be a real problem before the end of 1943. You can lower the number of duds by having the torpedoes strike obliquely rather than at right angles. I try to have torpedoes strike at an angle of 30-50 degrees. After 1943, duds no longer seem to be a problem.

• I leave at least 5 seconds between firings because of prematures: The second torpedo will sometimes detonate in the wake of the first if they are launched with not much time between them. Setting torpedoes too shallow (less than 3 feet) seems to increase the number of premature detonations, too.

• The estimate of the distance to a ship is an overestimate by quite a bit until the ship gets within a couple of thousand yards. Use the radar to get accurate distances.

• The radar can also help you estimate a ship's speed. 100 yards a minute equals 3 knots. Be sure to account for your own movement...I'm working on a scenario to help show how to use the radar for TDC inputs.

• The SD radar tells you how far away a plane is but not what direction. If a plane is low enough, it will appear on the SJ. Watch for small blips away from the convoy.

• Use the offset dial on the TDC for ships that are turning at the time you fire. The TDC assumes the target will be moving straight ahead on the course given at the time of firing. If the target is turning, it won't make as much progress in that direction and using a non-zero offset can account for that.

• A rule of thumb is that each degree of offset on the TDC gives you a spread of 17 yards for each 1000 yards to the target, assuming they will impact at 90 degrees. For example, if I launch two torpedos, one with a 0 degree offset and one with a 2 degree offset at a target 1000 yards away, the spread between them will be 34 yards. At 2000 yards, the spread will be 68 yards. There's a table at Jim Atkins's site with the exact values, but this rule of thumb will get you to within 10 yards of the table values for offsets of 5 degrees or less at a distance of 3000 yards.
  
  (Note to the geometrically minded: This rule of thumb works because the limit of sin(x)/x [x in radians] goes to 1 for small x. The difference between the angle in radians and the sine of the angle is less than half a percent at 10 degrees, and less than half of a thousandth of a percent at 1 degree. Most of the error in my rule of thumb comes from approximating 1 degree as 0.017 radians. But 17 yards per 1000 yards per degree is easier to figure in my head than 17.5 yards and is good enough for all but long range shots. )

Miscellaneous

• Been playing on 100% realism and feel like you can sink anything that comes your way? Change the combat setting to its highest setting (115% realism) and get your teeth kicked in. The escorts drop their depth charges much deeper at this setting. Simply going deep will not save you. If the escorts get you pinned down, you'll have to work alot harder to come out unscathed than you would at 100% realism.

• It is NOT necessary to have Patrol Disk #2 in order to play custom missions. Simply copy the missions into the same directory as the historical missions (c:\whatever\silent\scen). You may have to name them "histxx.scn" as well, where xx is 00-99, but be sure not to overwrite missions that are already there. You may have trouble if the missions take place in a patrol area that you don't have, though.

• You can play the game without the CD if you do a full install and then copy the last movie to c:\whatever\silent\bud\10.smk. Be sure to modify the shpath.ini file to point to c:\whatever\silent\bud\. Be warned: 10.smk is about 17MB. With the CD player free, you can use it to listen to music, like the Das Boot soundtrack, for instance. :)

• To find the password of a custom scenario, examine the file with a hex editor. (I use "debug" under DOS and "od" under UNIX.) The password begins 50 bytes after the end of the word "WORLD-x.WLD". To decode the password, subtract the following hex values from the password's ASCII values: 0 2 1 e c 3 4 6 5 a d b 9 8, i.e. subtract 0 from byte 1, subtract 2 from byte 2, subtract 1 from byte 3, etc. For example, if the encoded bytes in the file are "cqn..etgh" (ASCII hex: 63 71 6e 81 81 65 74 67 68), then the password is "comsubpac": 63-0=63 71-2=6f 6e-1=6d 81-e=73 81-c=75 65-3=62 74-4=70 67-6=61 68-5=63.

• Bug: SH has locked up on me several times if I go to the chart screen while at the periscope screen with the ship ID book pulled up. I've never locked it up any other way. This bug cost me a shot at the Yamato and a number of other ships. It's hard sometimes to remember to change back to the gauges before leaving the periscope screen when you're closing a ship and every second counts...

• Bug: If you select a torpedo on the torpedo screen and then go to another screen, when you come back to the torpedo screen, the torpedo you selected will have disappeared. (First noted by Bram Otto on the Silent Hunter message board.)

• Bug: If you move a torpedo out of the tubes with "Auto-Load Torpedoes" selected, the tube will reload properly, but the torpedo you took out will never properly unload. It will remained grayed out for the remainder of the patrol and you won't be able to use it. To prevent this, make sure you de-select "Auto-Load Torpedoes" in the options screen.

• Possible bug: If you save a game in career mode when there is fog, when you load that saved game, the fog will be gone. This has happened to me several times. If you are on the surface near a convoy depending on the fog to keep you hidden, this bug can get you detected and killed.

• Bug in the Scenario Editor: I've had to turn off the "limit subs by date" option in order to get the sub I wanted, even though it should have been available at the time in question. With the option on, if you click on Tench class, you get the Gato subs. I think it may be a problem with the Narwhal or Barracuda class not being available at later dates, so that when you select the classes listed after them, you get the subs of the class before the one you select. (I didn't say this very well. I'll try to write it more clearly at some point.)

• Possible bug: Once when I returned to port, it said the year was 2370 or something crazy like that, well beyond this century, and wouldn't let me go back on patrol because the war was over. I think what happened was that I ignored the OOD's warning that we were low on fuel so that I could attack one last convoy and the fuel needle dropped below the red mark. I wonder if this didn't get translated into a negative amount of fuel when I returned to port, which overwrote the year field in the save game. This was in version 1.2 of SH, I think.