Target speed calculation made easy

[Daniel Prates]

Originally Posted by Rockin Robbins

I know! Let's decree that the ratio between the diameter and circumference of a circle must be 10 for ease of calculation! Since when is ease of calculation justification for the destruction of natural truth?

You clearly feel very strongly about this, eh?

I think that anything we're used to, will do just fine. Being from a metric-country myself, I can tell you that since we all grow up knowing it, it seems very natural and intuitive - and that the anglo-american system seems very unnatural and basically weird. The problem with "natural truth" is that nowadays it is impraticable to have mearurements based on the size of the arm of some long-ago dead king or something.

Now, it is obvios that some things can't be tampered with. Did you know that the french, during the early ears of the revolution, decided to convert the HOURS OF THE DAY to a metric-sort-of system? There would be 10 hours in the day or something like that. I think that they went a bit too far on that.

[TorpX]

Let's decree that the ratio between the diameter and circumference of a circle must be 10 for ease of calculation!

RR makes a good point.

In many cases, one system is as good as another. I learned the metric system in school and liked it at the time, but don't see any advantage to it now. There are many physical constants which do not fit well in any system. Like the acceleration of gravity, g, or the speed of light, c, or Avagodro's number, etc. Civilization does not collapse because there are 24 hours in a day, months are not equally long, or there are 365.25 days in a year. (One of the things I like about the English system, for example, is that in physics, a foot-pound is easier to visualize than a Joule.)

BTW, I always thought it curious that the KM used metric-meters and English knots. Can anyone explain this?

[Daniel Prates]

Originally Posted by TorpX

BTW, I always thought it curious that the KM used metric-meters and English knots. Can anyone explain this?

Up until WW2, germany used metric values for everything, but I suppose "knots" was mantained for naval purposes since it was so traditional. It's not the same for instance in aviation, where airplanes would use kilometeres for both range and altitude, and km/h for speed.

Russia used this same system up until the fall of comunism.

[Rockin Robbins]

The use of knots exposes the Achilles Heel of the metric system. The numbers don't mean anything. They are all in the wrong ratios to each other to conveniently describe the relationships of natural objects, which perversely cling to proportions like 1/3 or 1/5, how many sides on a snowflake? Bet it isn't ten.

But the knot is a great unit because it has a relationship to a degree of longitude anywhere or a degree of latitude at the equator. There are 60 nautical miles to a degree. It is no coincidence that there are 60 minutes in a degree as well, is it? This has connections with our measurement of time, distance and angles. Now toss a metric measurement in there and all those obvious relationships just get entirely covered up in nonsensical decimal places of numbers in the power of 10. Nice even, obvious proportions hidden by the use of inappropriate units.

For instance, let's pick on the famous three minute rule we use in targeting. The number of hundred yards traversed by the target in three minutes is its speed in knots. Why? Because we have chosen to define the units to all have even relationships as shown above! The units make sense.

Of course we can do the same thing with the metric system in meters, we just have to pick the units to show the result, so we end up with the number of hundred meters traversed in three minutes and fifteen seconds is the speed in knots. Why the odd number, 3:15? Because the units have no relationship to each other. We've concealed a very important relationship between distance, time and angles. How many people have had to ask the question "Why 3:15?" They can't see the relationship. Inappropriate units hinder understanding of reality.

Even the Germans had the sense to use knots. There's a message there. (I'll bet the French aren't smart enough to use knots. They're the prime sponsors of the metric system.)

As much as anything else, the metric system is a proclamation of the political system of Revolutionary France in the first decade of the 19th century. Yes, they tried to make 10 hours per day, 10 days per week and have a metric year redefining the month and wiping out the relationships between lunar and solar movement in telling time. After all, man's stupidity is the measure of the universe. Be damned with real relationships, ease of calculation will be king even if the resulting numbers no longer calculate anything.

From now on all families are required to have ten children. Triangles must have ten sides.

You know I did find just one just about perfect decimal relationship. When a mixture of gas and air ignites in the engine of your car it expands almost exactly 1000 times. All together now: Metric System! This is too much fun! I hope I'm being entertaining as well as thought provoking. This kind of contention should be fun.

Actually the gist of my argument in favor of the appropriateness of the English system of measurements with all its charmingly archaic units is that they, like the natural world, tend to be proportioned by the ratios of small prime numbers or the products of small prime numbers, 1, 2, 3, 4, 6, 8, 12. Isn't it interesting that the number 5 rarely occurs? 1/5 is also a rare relationship in the natural world. Of course these relationships weren't chosen purposely in the way we think of selection. They came from simple observation of the proportions primarily of the human body. Of course the proportions of the human body are echoed in the rest of creation as well, but they had no way of knowing that. They just did what worked. There's an honesty to that. And a potential tragedy if in the name of ease of calculation we obliterate the wisdom contained in those units.

[TorpX]

One of the things I like about the english system is the degree-minute-second measure. One can devide 360 into 2,3,4,5,6,8,9,10,12,15,18,20,24,30,36,40,45,60,72, 90,120,180 parts (did I miss any?). Of course one can use decimal degrees or minutes instead.

I remember in trig, radians were used a lot, but outside of this I don't see too much use for them. I wonder what a carpender would say if you asked him to build a staircase with a slope of pi/4 radians?

[Dogfish40]

Originally Posted by RedHammer

I missed the Nagato battleship I was aiming at and instead hit a carrier far behind.

Sorry, It seems that none of us newbies can elaborate exactly how much we need the Auto Speed Determination of the chronometre to even get started using a manual tdc. Because the issue is this simple: We cannot hit anything of what we are aiming at. As in, nothing, maybe by luck, if I crazily enough manage to determine the speed, by a wild guess, then maybe I hit once or twice.

Right now, It would be easier for me to put everything on Zero on the TDC, and just aim ahead of the enemy ship I`m shooting at, and simply develop a feel for how many clicks in the periscope, ahead, of the enemy ship, I have to shoot, to get a hit.
But for real.. Who had time and resources enough to practice that.. that person would not be a sub captain for long..


S! to all


SK

Ahoy RedHammer
After reading and rereading some of the the patrol reports of the Fleet boats from the war, You are not far off in your feelings on the matter. In the early part of the war especially, the skippers were frustrated by the very same thing (Apart from the fact that the fish were faulty). I have read too many instances to count of perfect setups at 1000 yrds, 90 degree or comparable AOB, firing 4 fish and ALL MISS!. This is with all the personal assisting the Skipper! Most all torpedos fired at enemy ships in the first year of the war were misses. I've noticed in the game that ship's are taking evasive manuvers as soon as the fish reaches some visable distance, particularly in daylight and it doesn't take the ship much to adjust it's course and have the fish miss. So when you take your calculation, best fire a spread if you attacking during the day.
Point is, don't be frustrated. This is what the Fleet boats in WW2 are all about.
Good Hunting

[Rockin Robbins]

When you're first starting out I recommend that you leave map contacts on. Then with your pencil, plot a target position, then another position after 3 minutes. Measure the distance between the two points with your compass. The number of hundred yards between the two points is the speed in knots.

Now you can extend a line between the two points and forward in the direction of travel. With your protractor you can measure the target's course.

This is MUCH more accurate than the stadimeter auto speed and course thing, which is ALWAYS wrong.

If you wish, you can transition to finding the two positions with stadimeter and plotting them manually with map contacts off. Or you can find the 2 positions by active sonar and manually plot them.

I find that map contacts on is just as historically accurate so long as you are equipped with radar. Real radar gave more accurate measurements than our game with map contacts on anyway because the radar was analog and the game has binning from its digital nature.

They also had an entire crew assisting them, a whole collections of tools we don't have a clue about in the game and binocular vision with peripheral capability giving them a much fuller perception of their environment than we have. At best, SH4 lets you experience some of the experience, make some of the decisions and experience some of the dilemmas real submariners did.

But getting all nitpicky about realism is kinda foolish in a game where realism isn't on the menu. You can't even get cold and wet for 4 hours standing watch in freezing rain!

So play in a way that can teach you the concepts of torpedo targeting. That's about the extent of possible realism here anyway. Leave the map contacts on, especially at first. And consult the fun meter once in awhile. If it isn't at 75% or better, change the way you're playing.

[Dogfish40]

Damn Robbins,
If I had teachers like you when I was in school I would have been there a lot more! A compliment. Never stop your posts, I learn every time I read 'em.
Rock On
D40

[Jax von May]

Originally Posted by Shigawire

I want the nomograph in SH4 asap. Is there any way to get it in?

Loved it in SH3..

This is Wazoo's nomograph mod for SH3




The 3 lines at the bottom is the nomograph. If you know any 2 values of the 3, you can discover the 3rd unknown value. If you know time travelled, and distance travelled, you can find speed. If you know speed and time travelled, you can find distance. All you need to do is make a line between the 2 known points, and the line will cross the 3rd line where you will find the value you were looking for.
Quite ingenious.