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Manual Navigation

In Silent Hunter

For an added challenge when playing Silent Hunter, try navigating your boat without the use of the Waypoint Selection function or the Patrol Zone Navigation Chart. Here's how:


1. You will need a printed out Patrol Zone Chart, a ruler and a protractor.

2. During a war patrol, you will not use the navigational chart at all, with one exception.

3. You will not use the Waypoint Selector to plot any courses.


1. Download your assigned patrol zone chart from the Subsowespac website and print it out. The larger you can print the chart, the better it is. In my case, I printed a copy of the chart using A3 paper size. In the following discussion, I will refer to a section of the Southern Japan PZ Chart.

2. The grid squares on the Silent Hunter PZ Charts are roughly 95 nautical miles (nm) from N-S, and 80nm from E-W, as measured by the mileage on the speed gauge of the boat. This seems to be standard across all of the Silent Hunter Charts that I checked. The grid lines on the charts, however, are not aligned with any standard lines of latitude or longitude, such as whole degrees.

3. To identify the latitude and longitude of the grid lines on your chart, you have to go into the Silent Hunter game and take a boat into the PZ. Once in the zone, use the waypoint plotter to plot a course directly onto a grid line intersection. When your boat has reached that intersection, putting the mouse over the boat will indicate your position in degrees of latitude and longitude. Mark those on the border of your chart. For the SJ PZ, the intersection of areas SJ-7, SJ-8, and SJ-9 lies at 31-58 North and 135-54 East.

4. By doing this on adjacent grid line intersections, you can quickly calculate the N-S distance of a grid square in degrees of latitude, and the E-W distance of the grid square in degrees of longitude. Note* This will not be standard across all charts. For the SJ PZ, the intersection point of areas SJ-6, SJ-7, SJ-5, and SJ-9 lies at 31-58 North and 133-57 East. The next intersection to the west is position 31-58 North and 132-00 East. Likewise, putting the cursor on the port of MOJI, shows a position of 33-54 North, another grid line on the chart.

5. Determine the scale of your chart by measuring one grid with a ruler. This will tell you how many nautical miles to the inch. For example, on my chart copy, 1 inch is equal to 32nms.

6. Finally, you calculate the distance in nautical miles for the degrees of latitude and longitude. This information is useful when you need to pinpoint your location on your chart. For the SJ PZ, therefore, we have LATITUDE: 1 grid = 95nm = 2.9375 inch = 116 minutes (33-54N – 31-58N). Each inch = 39.5 minutes of latitude. LONGITUDE: 1 grid = 80nm = 2.5 inch = 117 minutes (135-54E – 133-57E). Each inch = 46.8 minutes of longitude.

7. Final note: On the charts that I checked, the size of grid squares seemed to be constant at approximately 95nm x 80nm. The scale of the charts also seemed to be constant. In my case, with the charts printed on A3 paper size, 1 inch = 32nms. However, the size of the grid squares in degrees of latitude and longitude is not constant across charts.


1. When you "Start a War Patrol" in Silent Hunter, you will be taken to a screen where you are given information, such as date, time, how much fuel you have consumed on your transit to the PZ, etc. What you want to jot down is your position, listed on this screen in degrees of latitude and longitude.

2. Locate your position on your printed chart. See Section B-6.

3. Now click the mouse and start your war patrol.

4. Immediately zoom the game's navigational chart to at least 8x. At this magnification, you should not be able to see any grid lines or "Sighting Squares".

5. Exit the game chart.


1. Now you can plot your course. On your printed chart, decide the next waypoint that you want to reach.

2. Using the ruler, measure the distance between your current location and that waypoint in nms. (For convenience, I used an index card as a ruler, marked off in nms).

3. Using the protractor, measure the heading that you will need to take to reach that waypoint from your current position.

4. Now go to the Control Room. Go to your required heading (Be accurate!!), and get underway. Speed is irrelevant, unless you are attempting to be at a certain location at a certain time (for a pilot rescue, for example). It makes no difference if you are submerged or surfaced.

5. When you get underway, mark down the mileage listed on the Speed Gauge.

6. When you have traveled the necessary distance in nms, and on the proper heading, you should be at your waypoint.


1. As with a real WWII sub, there is no way to know where you are unless you can a) see a navigational marker such as land or b) get a star-sight and a position fix.

2. In the first case, if you have plotted a course that will take you close to land, use the periscope or go to the bridge to look for land when you believe you should be able to see it. This can help confirm your position, but it is not reliable. You cannot be sure that you are seeing the correct landfall, nor can you accurately tell how far away the land is.


1. To accurately confirm where you are, you need to take a star-sighting, as follows. This is the only time you may use the Silent Hunter Chart for navigating during your patrol (I do use the chart for combat engagements once I've made visual contact with the enemy).

2. Right after midnight each day, go to the Captain's Cabin to check the weather.

3. If the skies are overcast, or if it is foggy, you cannot get a position fix. Under any other sky conditions, you can take a star-sighting. You must be on the surface.

4. Go to the Silent Hunter PZ Chart (minimum 8x magnification remember) and put the mouse on your boat. This will give you the Latitude and Longitude of your current position.

5. Go to your printed chart and find that position. Compare it to where you were supposed to be. If you are where you thought you should be, you are a true navigator. If not, you must adjust your next plot.


This Manual Navigation Option somewhat recreates the challenge faced by WWII US submarine commanders in the Pacific when dealing with outdated, inaccurate or non-existent navigational charts. It greatly adds to the challenge and the realism. In addition, by not using the Silent Hunter navigational chart except for a daily position fix, or after visual contact with the enemy has already been established, you will find it much more difficult to locate targets. You will not be able to see 'Sighting Squares' on the chart, and you might not actually be in an enemy shipping lane area due to navigational error. Especially without SJ or PPI radar, you can easily pass a target just over the horizon and never know it. If you encounter several days of bad weather, where fixing your position accurately is impossible, you will be facing the same uncertainty as faced by the real boats of WWII.

At first glance, the above 'preparations' would seem to require a lot of work, but it's not difficult to do, and only requires minimal time. Any math is quite basic.

It does take a bit longer to conduct a war patrol, but once you get the 'feel' of the boat, a war patrol does not take much longer than normal. For most Pacific Thunder participants, getting a war patrol 'overwith' is not really the goal anyway.

It is obviously important that you take great care when in narrow and/or shallow waters. Stay on the bridge, or make frequent looks through the scope. Look for land, and check the fathometer regularly. Remember that you cannot go to the Silent Hunter navigation chart except for one fix a day (weather permitting). Negotiating through narrow channels or among island groups is tough. A Photo Recon assignment presents a real challenge.

Mark down the measured distance to each waypoint carefully and make sure to follow your plotted course. Even a minor mistake can put you way off course and possibly in dangerous waters. I will normally lay out my entire patrol track for the day right after fixing my position and write it down on a piece of paper. It might look like: "hdg 275-48nms/hdg330-26nms/hdg045-62nms".

Unless you are in open water, it is difficult and dangerous to run at high time compressions. The highest I feel comfortable using is 128x. You need time to react to a sudden landfall, or sudden shallow water.

After an encounter with the enemy, you will often be off-the-track and not sure of your position. It can be useful to remember the heading last used by the enemy and follow it until a star-sighting can be taken after midnight or you sight a landfall.

Copyright © 2002 by George Southrey. Used with the author's permission.