Guides and Training

[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.

[norppis]

Oh wow, as a new subsimmer these are veery helpful!

[I'm goin' down]

all of the links are great. For attacks, if you want to start with the basics, I would look at the constant bearing technique, and move on the the Dick O'Kane method. When you get really good at those, move on to manual targeting using the Easy Aob mod, the OTC mod, or, if you have lots of time on your hands, the 3D TDC and Radar Range Mod. Mobo is the most incredible program in the forum. It will knock your socks off.

Just so you know, RSRDC is a mod that mirrors Japanese convoy and task force traffic in the war. So, for example, if you want to fight in the battle of Midway, the enemy fleet will be at that location in June '42. Same for Coral Sea, the Marianas Turkey Shoot, etc.

[ReallyDedPoet]

Great job here RR

[Rockin Robbins]

Thanks RDP. I just have to find a home for my longer videos. You Tube has me chopped off after 8 minutes and other homes have been too temporary. Still working on it!

[MattM1121]

Originally Posted by Rockin Robbins

Thanks RDP. I just have to find a home for my longer videos. You Tube has me chopped off after 8 minutes and other homes have been too temporary. Still working on it!

Before RL got in the way I managed to DL some of your videos. I was looking at them last night and thought I might be able to run them through an AVI compressor to get them down to a more manageable size. Unless or course you've already done that.

Does SubSim have a place to upload them? If so is there a size limit?

[fright52]

Is there any basic tutorial that shows how to use navigation tools for plotting course, finding bearings etc. Tired of zig-zagging and making "donuts" in the pacific. Ubisoft manual leaves a lot to be desired for beginners.
SH4 is fantastic! Just tired of dying and not knowing why. Help greatly appreciated.

[magic452]

Welcome to the boat mate.

It's pretty easy. Go to the navigation map, that's the second button in from the left on the top row. Double click this button. That opens the navigation map.

On the lower row of buttons the third on in from the left will say "Plot course". Just click this and a line will show on the map. One end of the line is anchored to your sub. The other end is at your mouse pointer. Just move the mouse to where you want to go and left click, that will place the end of the line where you click and the sub will follow that line, it's your course. You can click on the second point and start another line to a different place on the map and click there and a second line will be locked. You can set way points in your course to take you any place you need to go.

At any time you can click on any way point and drag it to a different place. You can also click on any way point and release the mouse button and draw a new course from that point and any way points after the one you clicked on will be erased.

If you turn off the plotted course using the compass you will head where the compass is clicked. If you click the E you will change course to the east. To return to your original course there is a button in the bottom row that says "Return to course" Click that and you will head to your next way point. If you have a way point set anywhere you will see a line from your sub and it will go to the next way point.

The three dials on the lower right are for speed, course and depth.
there are tabs under each and clicking the tabs will bring up different dials that will do the same things.

Read the sticky post at the top of the main page and there is a ton of information there.
try this one
http://www.subsim.com/radioroom/showthread.php?t=107783

And this one.
http://www.subsim.com/radioroom/showthread.php?t=146795

Magic