Sub Skipper's Bag of Tricks

[Rockin Robbins]

Generally, I'll allocate two per target, one a quarter of the way back from the bow or aimed at the first crane and the second a quarter of the way forward of the stern or at the aft crane. If that doesn't sink 'em it stops them to be mopped up later.

[ichso]

Hi,
I think you all know the problem of setting up an attack when your target is still far away. AoB can be estimated roughly at best and therefore the ship's course also.
Without radar for long distance range estimation you would usually have to get pretty close (something about medium range) before you can make any precise assumptions about your target's movement. Here is a little workaround, that will allows one to estimate the target course when it is still far away. It's more like a little trick than a complex technique so it might be well known already. But let's start:

I got in front of the little convoy to do the rest of the approach from beneath the surface. The approach was already on the way for ~20min now.


First thing to do is to mark your own position on some empty spot on the map and use it as starting point for your observations.

Keep course, take a reading of the ship's bearing (don't forget to calculate true bearing from that) and draw a line from your position onwards in the direction of the true bearing to target. The length doesn't matter as we don't know the range to the ship yet.

From all the previous observations when getting in front of your target on the surface or from using passive sonar you should have already gotten an idea how fast the ship is traveling. Then you approximate it's speed which is mostly a thing of experience values here.
You should be able to tell whether it is moving at fast, medium or slow speed. But what that means for the actual ship depends on your judgement. A slow moving passenger/freighter convoy for instance, I would estimate as ~6.5kn from my previous experiences, so I'm using this value here.

You then wait a fixed period of time. In this example I'm using 5 minutes.
Use the stopwatch and after this time expired let the stopwatch keep running. Otherwise you won't be able to continue tracking your own movements afterwards.
While doing this there's enough time to estimate and draw you position after 5min. Here I'm moving at slow speed underwater = ~1kn, meaning that I will travel ~150y (heading south).

When the 5min have passed, take the second reading and draw another line only now originating from your new position.

So far nothing new. What I'm gonna use now is the fact that the target's speed will have it travel ~1100 yards during this time. See the nomograph on the right for this.
Now, with both bearing lines in place you only need to pick *any* spot on the first line and draw a line that will end on the second bearing line and has the lengh of 1100y.

Note that the first spot you picked there is most likely not the actual position of the target (relative to yours) because we don't make any attempt to get the range yet. The only thing that's important here is that the speed estimation is roughly correct. (And that your drawings are o.k. of course ).
But after encountering many many freighters at a speed of ~6.5kn (when moving at slow) you would accept this as a reasonable base for these estimations.

Here is an image of my in-game nav map to show what I mean.


The small line with length 150y is the way I travelled during those 5 mins and the lower circle shows the spot I picked arbitrarily for the target ship.
The target's course line reads something like 310° and when the vessel gets close enough to do a reliable range estimation you can draw it's real course line (relative to your position at least).

Knowing the course allows you to position yourself precisely, set a course perpendicular to the one of your target (for fast 90 or dick o kane).
Also the target AoB is then only one step away, especially when using an AoB-wheel.

Hope it's not all old news, just figured it might be helpful in some situations.

happy sailing

[Rockin Robbins]

Neat application for optical course determination. I might figure out a possible range of course, say from a convoy speed of seven knots to four or five knots. This would yield two possible convoy courses. Maneuvering yourself to take advantage of either, the real position compared to the two possibilities will allow you to refine your convoy's speed.

[swmicros]

Very good ichso, nice explanation. I have watched and studied the many tutorials on 100% realism but they (at least the ones I have discovered) all deal with the short range final delivery, not the long range approach. I could not figure out a reliable way to predict the target's course. I will definately try this out. (been schooled again!)

[liluoke]

thank you for such a helpful list!

[Rockin Robbins]

The entire goal of this thread is to take the scariest part of Silent Hunter, manual targeting, and convince you that you will be successful in short order. Then we aim to make it true.

Nobody needs to be afraid of manual targeting. There are so many ways to do it, you are sure to find a couple of methods you will immediately like. Once you're hooked you'll never consider going back to auto targeting again. That's a promise.

[TwinStackPete379]

RR is right, once i watched the Werner vids, it all made sense, and it's so gratifying when the fish hits after you've put together the solution piece by piece. This game is fun. Can't believe i only discovered it 10 or 12 days ago.

[Frederf]

RR suggested I transplant this explanation of how the nomograph works from another thread:

I think it's too easy to overestimate the complexity of the nomometer and treat it like it's some black voodoo magic. All it does is calculate time, speed, or distance if you know the other two things.

"How much time does it take to go a distance at this speed?"
Time = Distance / Speed

"How much distance is traveled by going speed for time?"
Distance = Speed x Time

"How fast does something have to go some distance within this much time?"
Speed = Distance / Time

These are the only three questions that the nomometer knows how to answer. If you want to know the course or angle or when the moon will rise, you need to look somewhere else. You ask by drawing a straight line through the two values you do know and the answer is discovered by finding where the line crosses the scale of the value you want to find out.

A practical example is (for me) commonly that I have plotted the target's location and I know its course and speed through previous calculations. I've decided that I want to shoot at the target when it gets to some specific future position since that makes for a good shot with short range and good angles. So I measure the distance from the target's current position to the desired future position and maybe it's 4600yd. Also say for example that the target is going at 8 kts. What I want to know is "How much time is it going to take that 8 kt ship to travel 4600yd?" This is important to me because I want to know how long I have to get into shooting position.

I pull out the ruler tool on the navigation map and I start a line from the 8 kt mark on the speed scale. I pull this line through the 4600yd mark on the distance scale until I cross the last scale, time. I notice that this line that passes through "8kt" and "4600yd" also passes through about 17 minutes. This tells me that something takes 17 minutes to go 4600yd at 8 kt.

Just for fun the problem can be extended. Using the previous result of 17 minutes until the target gets where I want him to be for shooting I discover that my submarine is too far away to make a shot. Oh no! Now I pick where I want to be to shoot which I measure to be 1200yd away from my current position. OK, I have 17 minutes to go 1200yd. How fast do I have to go? Leaving the right end of the line I made in the paragraph above at 17minutes, I drag the left end of the line around until the line crosses through 1200yd mark on the range scale. Then I look to the speed scale to figure out my unknown. The line crosses the mark at just over 2 kts. "I must go 2 kt to travel 1200yd in 17 minutes."

17 minutes later the 2 kt submarine has traveled its 1200yd and the 8 kt target has traveled its 4600yd. The nomometer has allowed me to arrive just in time.

[Rockin Robbins]

And I've been playing mods without a nomograph lately! When I loaded up TMO 1.8 beta, there was my old pal the nomograph again. It's great to have a refresher course on just how useful it is. Thanks Frederf!

[TwinStackPete379]

I just did my first O'Kane fast 90 after reading RR's tutorial. out the stern tubes at 2600 yds. that was way cool! both fish hit EXACTLY where i aimed for. that was FUN, I wanna do it again!

[I'm goin' down]

What is missing?

The fundamental concept of aspect ratio and AoB are laid out in Hitman's tutorial (pdf format) by the one and only Hitman. I recommend it be included for those like me who had no inkling of the issue and concepts to overcome in successfully executing a manual targeting attack.

[Rockin Robbins]

I don't use that because it's not realistic. Information on target lengths and heights was not available during World War II. Even if it were, cut-down masts, paint jobs to make it difficult to see mastheads, disguising of ships to look like other ships of different lengths and aspect ratios all took place. That will never be part of any tutorial I ever do. I will never advise anybody to use that method, as it is entirely bogus for use in US fleet boats. It was very rarely used on U-Boats as a last resort.

[I'm goin' down]

the point is that it teaches aspect ratio and AoB. It is a tool to help understand those features for those who are not familiar with them.

[Rockin Robbins]

Aspect ratio is not a legitimate targeting tool, especially for fleet boats. Not once in the entire war can I find a single instance of using aspect ratio or timing the length of the target by the wire. Both of these techniques enjoy a peculiar popularity here at Subsim and both are illegitimate techniques when applied to World War II submarines. As I said earlier, very rarely, U-Boats used aspect ratio as a last resort tool.

After-war analysis of targets sunk and not sunk by American submarines revealed that most of the time targets were misidentified. That means that if they had Capn Scurvy's perfect list of hull lengths, heights of all features and Hitman's aspect ratios, they still couldn't have hit the broad side of a barn.

The fact is that we had very little information of the true dimensions of any non-warship in the Japanese fleet. We routinely misguesstimated lengths by a factor of 2, misidentified tonnage by as much as a factor of 3, failed to identify the identity of most targets and in general made a mockery of any ONI manual that we had. Given all that, using methods that increase periscope magnification, provide perfect dimensions of every target on the ocean, eliminate all errors in the database, are illegitimate targeting tools if you care anything about realism.

These tools stand directly between you and understanding the thoughts and feelings of World War II submariners. Now if you wish to play an arcade game, have at it. That's not why I play Silent Hunter.

I firmly believe that it wasn't the captain's fault when many torpedoes failed to explode against the hull of his target. I don't believe they were in complete control of success or failure every time they mashed the fire button. I think our insistence that we should be makes a mockery of the simulation.

Many submariners died for reasons they were not responsible for. Many had spectacular successes for the same reason. War ain't fair. People die when they do everything right. Only failure can be guaranteed. Success is always a crapshoot. The resulting frustration is a central and necessary part of anything with any pretention of being a simulation.

That is why MaxOptics, SCAF, aspect ratio AoB determination or LOA timing past the wire speed determination will never be endorsed or taught by me. The most important ingredient in simulation is the unknown gotcha.

[Hitman]

Aspect ratio is not a legitimate targeting tool, especially for fleet boats. Not once in the entire war can I find a single instance of using aspect ratio or timing the length of the target by the wire. Both of these techniques enjoy a peculiar popularity here at Subsim and both are illegitimate techniques when applied to World War II submarines. As I said earlier, very rarely, U-Boats used aspect ratio as a last resort tool.

After-war analysis of targets sunk and not sunk by American submarines revealed that most of the time targets were misidentified. That means that if they had Capn Scurvy's perfect list of hull lengths, heights of all features and Hitman's aspect ratios, they still couldn't have hit the broad side of a barn.

RR is mostly right. The aspect ratio and fixed wire methods are not, by any means, historically correct for the us submarines, and in the german uboats were they come from they also weren't that much used.

In the us submarines, plotting was the main way of getting the necessary values for the firing solution. Plot was fed from periscope observations (stadimeter for distance, based on mast/funnel heigth estimates and AOB by plain eye observation) and then checked against the TDC position keeper. When radar appeared, this task was greatly improved in accurancy, because the distance could be accurately determined, but overall the method was still the same, only more precise. Developed in the interwar period, when submarines were thought vulnerable if close to the target, the method ensured that even long range shots could have accurancy, and that firing even without seeing the target was possible (Thanks to the position keeper).

The german uboats in turn resorted to other systems, and the plot was mostly unused. The only time when something similar was used was when overhauling in the surface a target, be it a convoy or a single ship. In those cases, the captain would rely to the navigator a crude estimation of distance and issue the proper orders to keep the uboat in paralell course beyond the horizon. The comparison of own uboat course changes and bearing lines gave the navigator an approximate idea of the enemy course and speed. And when in perfect paralell position, the commander would make some speed variations until the bearing stayed constant, showing true enemy speed. In other circunstances, mainly night and submerged attacks, the commander or IWO estimated all, distance, AOB and speed by naked eye, and if available, used the values gathered previously during the overhaul maneuver.

The aspect ratio system is derivated from the horizontal stadimeter present in early war uboats and interwar periscope makers, which was not unknown to the americans. It was a useful gadget in the peacetime maneuvers, where dimensions of target ships were well known, and it helped the commanders develop the seaman eye. But in wartime, for all circunstances explained by RR, it was mostly useless.

Not so much the fixed wire, which was still used, but again not as widely as plain eye estimate.

The reason I adapted them to a quick tutorial for us submarines was to get people started on manual targetting and familiarize them with some concepts. Since the AR and FW methods were useful in situations where target dimensions are know and there is no pressure on the shooter, they fitted well the concept of SH3/4 gaming. We don't risk our necks, and the limited number of ships in the game allows us to use it. And, in the same run, the player starts understanding concepts such as the non-linear change of AOB, and the sense of relative motion of the target. In my experience, after some time using the system, the user discovers that he has developed enough experience to tell the AOB by naked eye estimation, even in a 2D environment as a game screen. And the speed also starts being judged with some accurancy, at least in some 3-4 knots interval.

I don't however concur so much with the idea that it is impossibel to guesstimate more or less correctly a ship's length (Mast heigth is more difficult), because with some practice it isn't so difficult. There are certain naval construction rules that help a bit, because shipbuilders always tend to keep some proportions, and because a few meters up or down in length don't make a lot of difference for us.