Lenght of ship

[Rockin Robbins]

Where's all that rain I can drop on your parade? Oh, here it is, lurking above me!

First of all, determining target speed by timing target length by the wire is a technique that nobody used during the war. Why? Because we didn't know what the length of the target was. In SH4 our recognition manual has precise information about every single ship on the ocean. The real thing? Don't make me laugh. When it did have information it was often wrong. When it was right, the captain chose the wrong target anyway.

The majority of targets sunk during the war were misidentified. There was never any attempt to measure target speed by calculating from target length. It's a bogus technique that has for some reason, taken on a life of its own in Silent Hunter.

So using that is gaming the system, taking advantage of unrealistic information, just as those who know that by sonar you can hear screw sounds exactly two degrees to either side of the real bearing and then there is a sudden cutoff. They game the system to get an exact bearing to target by passive sonar when in real life the width would not only be wider, but the width would vary with conditions! Passive sonar bearings were about half as precise in real life as they are in SH4.

OK now that your parade is wetted down I'll let you get back to obtaining advice.

[razark]

Originally Posted by Rockin Robbins

...
When it was right, the captain chose the wrong target anyway.

The majority of targets sunk during the war were misidentified....

Some interesting statistics regarding that issue:

Unrestricted Warfare, Appendix 3, Page 1:

Unrestricted Warfare, Appendix 3, Page 2:

[I'm goin' down]

Who needs wily coyote? We have Rockin Robbins!

[CptChacal]

Originally Posted by razark

Some interesting statistics regarding that issue:

Unrestricted Warfare, Appendix 3, Page 1:

Unrestricted Warfare, Appendix 3, Page 2:

Wasn't JANAC controversial? I think O'Kane mentions at the end of his book that JANAC was discredited after checking with IJN records. Then new tonnage was credited.

[razark]

Originally Posted by CptChacal

Wasn't JANAC controversial? I think O'Kane mentions at the end of his book that JANAC was discredited after checking with IJN records. Then new tonnage was credited.

Yes, JANAC was not well received. I know there was at least one other list produced after the war that fell somewhat between the two. I had ready access to this particular table, and I think it shows the point.

If you'd like to ignore the tables, you can look at some other sources. I know I've read multiple times of task forces being reported with sightings of battleships, when in reality, there were only cruisers and destroyers present. Identification of targets with only quick looks through the periscope and out of date identification sources was simply not that accurate.

[TorpX]

The question of JANAC and IJN records reminds me of similer questions about German fighter plane production in WWII. The Germans claimed to have produced very large numbers of fighters, but when the losses, captures and such are added up, the numbers don't square. One author forwarded the theory, that planes sent back to the factory for repair, were counted as new production, and thus double or triple counted. Possibly, they were simply inflated because of political pressures.

The point I'm trying to make is JANAC was based largely on IJN records, and these records may not be accurate. Given the magnetude of their problems, it is easy to see why, keeping neat and tidy records, may not have been the highest priority.

[CapnScurvy]

With a new mod I'm about to release the Recognition Manual will have ship lengths added for every ship (see image below). I realize there are a lot of you that think the game uses accurate figures when giving mast height, ship length (no matter where you find the results), or draft depth etc. You're wrong. The game has a bunch of figures that could have been verified from the back of a cracker jack box.



These measurements mean nothing to a player who uses the automatic targeting method. The game happily calculates the targets position and speed (and why shouldn't it, the games the one that put the target in front of you in the first place!) and gives you a green light when its time to press the fire button.

Those of you who use manual targeting have to find range, speed, and Angle on Bow on your own to make a proper firing solution (or maneuver yourself soooooo close to the target, you can't miss). The point is the game didn't spend a lot of time putting in measurements that a manual targeting player could use. Nor, did it make the viewable game world correct to use any real world measurements. The Optical Targeting Correction mod will correct the game worlds view which was off by several degrees in width. In doing so, real world numbers may work as they should, I don't know, or care. The only factor I've every concerned myself about is what are the results of in-game play. If the games measurements read x amount high, x amount long and a correct range, speed or AoB can be attained with them, why do we need real world measurements added to a game that doesn't know how to use them correctly? As I said, the real world figures may work correctly with the optical changes to the game views after the OTC mod. What I've done is calibrated each height and length figure to provide as accurate a measurement as reasonably possible. The rest is up to the other factors in the game that make manual targeting the difficult process that it is (weather, lighting, detection, distance to target, movement of all factors involved).

[Rockin Robbins]

In other words, if the game is wrong about the length of the real ship, but uses that wrong length for in-game plotting and calculation, you'd better use the game's wrong number for calculations or you could miss your shot.

When in Rome do as the Romans do!

What kind of length errors does the recognition have compared to the in-game lengths? Is the percentage ever consequential? I'd think the masthead height errors would have much worse effects on shooting.

[Pisces]

Originally Posted by Rockin Robbins

...It's a bogus technique that has for some reason, taken on a life of its own in Silent Hunter....

It's not bogus, it's scientifically sound. It's just historically unrealistic. Well, for US atleast. Since the intelligence about those ships could not be trusted, or the Officer using it. BTW, the Germans did have special functionality in some of their periscopes ('Feste Linie im Raum', tr.: 'fixed line in space') to keep a gyrocompass-synchronised vertical line in their view. (Link)

Ahum,

In another post (I think it was the recently resurrected 'Clear the Bridge! Dick O'kane method' thread, ... yup it's post 7) you said:

In order to run, you must first learn to walk. And it's great if while you're only walking you can do some interesting things, like blow up enemy shipping. Just please make an agreement with me. After you learn to run, don't make fun of the people who are still walking. Don't make fun of simpler methods as "unhistorical" or "shortcuts." There are plenty of runners who still use the Dick O'Kane and John P Cromwell techniques to their profit. And some of those walkers, like I'm goin' down, will be passing you in skills in a month or two!

It works, 'fairly' quick, at least usually quicker than 3 minutes , it's (can be) precisely defined how to, and it's simple. What more do you want?

[Sailor Steve]

Originally Posted by Pisces

BTW, the Germans did have special functionality in some of their periscopes ('Feste Linie im Raum', tr.: 'fixed line in space') to keep a gyrocompass-synchronised vertical line in their view. (Link)

Could somebody translate that please? This is the first time I've ever heard of a gyro-stabilized anything on a WW2 submarine, and I'd like to know exactly how this thing worked.

[Pisces]

Originally Posted by Sailor Steve

Could somebody translate that please? This is the first time I've ever heard of a gyro-stabilized anything on a WW2 submarine, and I'd like to know exactly how this thing worked.

How about the torpedoes you shoot. They are gyrostabilised as well

Sorry, my German is barely enough to understand it myself. Maybe Google ist in ein sprechen mood.

[Rockin Robbins]

Originally Posted by Pisces

It's not bogus, it's scientifically sound.

I looked up "bogus" in the Rockin Robbins unabridged dictionary and it said "historically unjustified procedure." My post wasn't to tell the OP not to use the technique, but that actual use of that technique was impossible during the war.

The Germans had the capability to use this technique. They were fighting open societies which did not restrict or falsify information about their merchant ships. A Liberty Ship, for instance, was a cookie cutter thing where each ship shared waterline length, overall length, masthead heights and cabin configurations. It wouldn't be difficult at all to determine the numbers by trial and terror and then apply those numbers to hundreds of available targets with devastating results. But I haven't seen evidence of much or any use of this technique, even by them.

Japan, however, was a closed society. Very little was known about their merchant fleet. We knew some things about their war fleet but much of that information was purposely misrepresented. The state of global communications just didn't allow us to use "timing by the wire" or to calculate target speed by prop turn count as we can today.

But don't confuse putting something in historical perspective with telling a new player not to learn the technique. I did not do that. In fact, I joked that now that I had rained on his parade he could continue collecting information.

[TorpX]

I had worked out the technique years ago when I was still playing SHCE. I thought, at the time, it was a brilliant idea and that it would be a great help to me. I soon stopped using it. Why? Not because it was ahistorical, but because I didn't see any advantage to it.

If the target is abeam, one must 'add' the sub's speed to the target's. If the target is ahead this is not neccessary, but then your already lost your window of opportunity. If the target is far away, it will be hull down and you can't use it. If the Aob is small, you can't really tell when the stern passes the wire. When you put your boat on a normal approach course, frequently, the target will be moving very little, relative to the wire, making the technique unusable. In any case, I would still have to make a plot to obtain the course and range, so I would use it for the speed also. The timing target length, or whatever you want to call it, will not give you any information that you can't get form a good plot.

That said, I don't see anything wrong with using it. It may be ahistorical, but it is not implausible. Certainly, at least some of the IJN warships were distinctive and would permit its use.

[gutted]

The ship lengths that were in the printed manual were off. I created a tool that will fetch all the data you'd possibly need about each ship from the actual game files:

http://www.subsim.com/radioroom/down...o=file&id=1602

It was made for SH5, but will work for SH4 as well.

enjoy.

[TorpX]

Good idea!