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I could have sworn it was in, 'Clear The Bridge', however I have read so many books - it could have been a different Skipper.
Whomever it was wrote that upon reaching his assigned area, he tried 'All Stop' and performed high-scope & radar searches at that location all day. The next day he would move 20 nm, and conduct the high-scope search at the new location all day, sail 20 nm the next day, and repeat the procedure until he found a contact. Sadly, unlike SH1, SH4 doesn't model the larger horizon gained by using 'high-scope' searches, although in real life many patrolled using the high-scope farther horizon advantage. What SH4 does correctly is model the almost daily position reports the Japanese (and Germans) were required to report. These reports would be intercepted and decoded becoming the ULTRA reports our Commanders received, and that We receive in-game as the red boxes with directional tails on our chart/map screen, along with the position report messages. This is why it doesn't bother me that those position reports are on the Nav map, although of course there are too many in Stock... (as was the case in SH1) Unlike the Axis, US boats did as little communicating as possible - mostly none - because they were the 'silent service'. The few US wolfpack missions required some communication between the boats, and a small handful of boats reported that they were under attack, however most did not even report that. After a period of time they would be declared overdue and lost at sea. This topic, "The mathematics of roving searches" is very interesting and is interesting to compare with the above static search method that conserves some fuel. I've been a fan since the excellent tutorial on how to make a torpedo attack without the use of a TDC (S-boats didn't have a TDC) written by someone whose initials are, 'Frank Kulick'. Happy Hunting! |
I base my theories on those of Admiral Eugene Fluckey, who with the USS Barb found targets when nobody else did. He didn't know the shipping lanes because he couldn't open his game box and dig one up or do a Google search. In Thunder Below he goes into great detail explaining exactly what I've laid out. All things being equal, your number of contacts developed is proportional to the number of square miles of ocean surface you search in a day.
Of course that has to be modified by the length of the cruise, the amount of fuel you have and having enough torpedoes to cruise the distance without running out. Fluckey, starting his career when boats routinely returned to base without finding a single target, set the world on fire simply by staying on the surface, covering the most ground per day and using the longest range sensors he had (unlike SH4, radars broke painfully often). He pioneered using the scope on the surface, extended to its highest position to extend the horizon enough that he could double his visual search area. So in real life they had to use raindrop theory at best to search for targets. Because of hindsight, we might come up with better methods but they would be bogus, based on assumptions real sub skippers couldn't make. |
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I've started putting together a simple computer model to help out and give us some actual hard data to think on. I should have it done in a day or two. |
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Let's quote Admiral Eugene Fluckey, quoting himself on page 65 of Thunder Below, in a conversation with Admiral Lockwood, who Fluckey would replace later. Quote:
This was the most successful sub captain in WWII for innovation, turning a slow part of the war into a bonanza. Heck, he sank a train. |
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Sensor range (maybe patrolling works better with SJ-1 while lookouts work better stationary?) Target speed (maybe patrolling gives better odds of finding ships under a certain speed while having little or no effect on targets above a certain speed. Patrol speed (maybe patrolling at 10 knots doesn't significantly change your odds from patrolling at 3 knots?) The easiest way to get useful info that I see is just to write a computer program to try them all like 500,000,000 times. Oh, and I wasn't talking about radio stuff specifically. More along the lines of something as simple as taking a map and putting a pin in it for every contact report. You know where all the ports are, and often logical deductions can be made just by connecting the dots. Other efforts will provide more data to work with, but the basic concept remains the same really. In other words, if you never look anything up in your sh carreer, you get the amount on intel you personally generate (and probably don't store it all that well), whereas a sub skipper in ww2 was additionally getting intel from other sources. That being said, I don't tend to look up things very often as the information revealed can be way too precise. |
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That's a pretty good analogy there. Quote:
I consider this the beauty of my solution. I've used vector addition to subtract the target ships' speed. (This sort of thing was done with a 'maneuvering board' for various problems.) Working the problem this way, the ships in diagram 2 (if there are any) do not move. We need not make any assumptions of how many, or where the ships are located. All that need to be done is compare the respective areas cut out, of the moving sub and the stationary one. Quote:
Yes, thank-you. It's on page 54. I'm glad I'm not the only one who remembers that. I think O'Kane did a good job of explaining it. Quote:
Yeah, Ubisoft sure could have done better. Quote:
Not to criticize Fluckey, but iirc, he did run short of fuel on one patrol, and had to go home empty handed; the point being that roaming doesn't guarantee results, and may leave you low on fuel. Quote:
Not sure what you mean here. None of the math I've used requires quantum mechanics, string theory, or black magic. |
IIRC, there is no gain in efficiency below 10-11kts. So you won't gain any distance by going slower than that, but you will remain on station for more time. I guess the moral may be that efficiently patrolling a barrier longer than ~35nm will allow an increasingly large fraction of shipping to escape detection. However, a barrier shorter than 35nm allows you to spot anything transitting while moving slower and staying on station longer.
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Oh, been meaning to tell you that your link to table.txt above is broken. Quote:
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It's an exercise in relativity. The reason to use the ship's frame of reference is to visually display the area searched by the sub and the areas to which the sub is blind. Fig3 demonstrates that, as the speed of the sub increases relative to the speed of the ship, the gaps in its search pattern shrink until there is noplace to hide |
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We can make reasoned generalizations about the traffic direction in an area. We can also generalize speeds by saying that almost all merchants are doing 10 knots or less. This isn't black magic. Not unless you consider understanding the probabilities of your tactical situation such anyways. |
No, you're right. We have to simultaneously prepare for the sensible and for chaos. Most of the time we have mutually exclusive choices with advantages and disadvantages for each choice. Running a submarine is hell. So many ways to make wrong choices while trying to manipulate the odds in your favor. It's like fishing where science, superstition and guesswork play equal and often indistinguishable roles.
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Yes. This is exactly right. Quote:
Yes, he did very well, but O'Kane also did very well. Flucky's success was also due to his willingness to hunt in shoal waters, that other skippers avoided. Quote:
This is also correct. Quote:
You know, you're right. They had to know this. Perhaps they didn't put it in all the usual manuals because they considered it elementary. |
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First, it's not really a particularly romantic subject. Sure, everyone likes looking at battle tactics, but the mundane details of how to steer the ship aren't particularly sought after information in general. Second, it's not particularly useful information outside of a martial context. In the civil world, rendezvouses at sea aren't really commonly done and when they are both parties are probably willing to openly communicate with each other. The closest common concern that I can think of in the civil world would be potential search and rescue operations and buoys and such. The theory there is pretty different though, since in that case you're trying to find something that's either stationary or drifting. |
Interesting reading...
The most enjoyable part, so far, was...
"Gotta agree here. The actual math on this sort of thing was probably worked out a *long* time ago due to how pertinent this thinking is to every navy on the planet. The thing is that I have no idea where to find the information. I can most likely find the answer for myself more easily than I can research it." Quite right…WRT the real world, the math in this thread isn’t entirely complete, but it is very much on target, since the solutions in real life are based on vector analysis. None of the naval commanders in the USN during WWII (including O'Kane and Fluckey) had to make things up entirely on their own; there was a large knowledge base available from the pre-war "Battle Problems", in which the submarine force was used almost exclusively for scouting, searching and patrolling large open ocean areas. Following the war, specific methods for search, patrol and detection, became part of the tactical doctrine for USN and NATO navies that is (or at least was) in ATP-1 (Allied Tactical Publication) and other ATP series books, as well as NTP (Naval Tactical Publication) series books. Of course, they are all classified; at least CONFIDENTIAL and most at SECRET level. Another problem is that almost all of the doctrine used since WWII is based on using aircraft to conduct large open ocean area searches. Oh, well... The fundamentals are all part of the science of Operational Research/Operations Analysis, going back at least as far as the late 19th/early 20th Century. OR/OA became a recognized science during and after WWII and is an essential element of Military Science today. If you want a more thorough discussion of the real world math and real world sensors, much of the fundamental theories and math is openly available. You might consider getting and studying “Naval Operations Analysis” and “Principles of Naval Weapons Systems”, both from U.S. Naval Institute Press. I rummaged through an old Cruise Box ("Sea Chest" to some) of mine and found a copy of OEG Report 56, "Search and Screening" and some big 3-ring binders with hand-outs and class notes from Sub School, Destroyer School and War College. So, from the “real world” I offer the following… The problems you are looking to solve are mostly dealt with by “Area Searches” and “Barrier Patrols”. The latter is more commonly used because the subject(s) of most searches is/are operating in one of three specific cases: 1. the target’s intention is to traverse a fairly straight “channel”, which may be a wide portion of the ocean (such as a known or suspected shipping lane), or; 2. the target is proceeding from a known point on the ocean (typically an island or harbor), or; 3. the target is proceeding toward a known point on the ocean (a mission objective area or an island or harbor). In case 1, the target vector velocities at all points are parallel and equal, a translational vector field, as shown in the OP. In case 2, the target vector velocities are all equal but are all directed away from that specific point, a centrifugal radial vector field. In case 3, the target vector velocities are all equal but are all directed inward toward that specific point, a centripetal radial vector field. In each case the problem is solved using either crossover patrols (when aircraft are searching for ships) or linear patrols (when ships are searching for ships). Let’s call the speed of the target “u” and the speed of the search vehicle “v”. There are many variables that we don't have in the game, such as multiple sensors with different detection probabilities for different types (sizes) of targets under various weather (signal propagation) conditions. So, ignoring all of the variables that are not present in both the game and in real life, the simplest crossover patrol solution, gives us the geographic path, or course of the patrolling vehicle, across the width of the area being searched, to be done at an angle “a” from a line perpendicular to the axis of the search area, such that sin a = u/v. In real life, the width of the search area is based on the "sweep width" (sensor range) and desired probability of detection, applying the Inverse Cube Law of Detection and the normal probability tables (found in OEG Report 56), not "black magic" but requiring either a computer or good calculus skills...too much for any other than the hard-core fans here...yes? You’ll note that solving for the angle "a" is essentially pointless as u and v get closer to the same value. The crossover patrol for ships searching for ships then becomes a linear patrol instead. The solution is to convert the angle from sin a = u/v into tan a = u/v, which commonly produces a recommended course line 45deg off the axis of the search area. The usual assumption is that surface ships will proceed at approximately the same speed; if Intelligence tells you otherwise, act on it. BTW, it works both ways, giving us either an Advancing Barrier Patrol or a Retiring Barrier Patrol...and it can be stationary as well, useful for "choke points". You'll also note that none of the real world solutions offers a 100% probability of detection; the goal is to do just as others have stated here...cover the maximum search area possible in the amount of time available, with the highest detection probability possible. BTW, you might be surprised to know that the search patterns in stock SH4 (and SH3) are almost right out of ATP-1 and the OA (Operations Analysis) books; they include the “Ladder Search” the "Crossover Barrier Patrol" and the "Expanding Square Search" (which the developers got completely backwards!!!). Unfortunately, none of them can be rotated; they are all fixed with a search axis along straight N-S/E-W lines and course lines of fixed length...oh well, again. |
So my computer simulation is almost done. Ships and subs are moving and subs are detecting ships. And data is being stored. All that needs to be done now is making it spit out usable statistical data. I'll get to that in the next couple of days.
If you have any particular patrol patterns you would like to see tested, I would be happy to run them. just format them like this for me: All waypoints should be a pair of coordinates, listed in nautical miles. The origin is the southwest corner of a hypothetical north-south running shipping lane with dimensions of 55 miles east/west X 500 miles north/south. The sub will loop through the waypoints if it finishes its path. The program will run the patrol at all speeds from 1 to 20 knots. For example, the below is a 28 X 28 mile square roughly centered in the north/south axis. 41.5, 213.5 13.5, 213.5 13.5, 241.5 41.5, 241.5 |
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Well, that explains why we don't see the these at hnsa.org. Quote:
Not surprised; I mean about the getting it backwards part. :03: |
Hello TorpX...
You're right..."overclassification" was a real concern during the 60's, 70's and 80's. At one point someone had the bright idea that we would be better off declassifying everything but a very very few documents. The theory behind that was that classifying information just told the "enemy" what to look for and what was good information worth getting and keeping; we were just making his job easier for him. One could imagine what it would take for some "enemy" or potential enemy to have to collect EVERYTHING and then wade through it to figure out what was good and worth keeping. Of course that was then and this is now...the computing power available today would make that "sorting" job much easier. Yeah, the volume of dry, boring text and mind-numbing graphs, charts, tables, etc. is enough to make just about anyone put those books down and walk away. The 3-ring binders I have are each 3-4 inch "D" ring binders and are overflowing with that stuff (all stamped SECRET, but there is a letter taped to the inside of each front cover that identifies all of them as being past their respective "automatic downgrade/declassification" dates). Not to mention more than 350 pages in OEG Rpt 56; it's published title was "Search and Screening", certainly something you'd grab off the bookshelf if you saw it there!!! Glad you enjoyed reading it. BTW, if you (or anyone else) knows how to rewrite the "Expanding Square" search to make it work correctly, please let me know...I would use it in both SH4 TMO and OM. P.S. I asked Gene Fluckey once about his "daring-do" in risking his boat in shallow, poorly charted and/or ASW infested waters...he laughed and said nobody else was "stupid enough" to try it. Then again, you gotta' admire someone who said he'd pass up the chance to sink an enemy ship in exchange for rescuing some of our downed fliers. |
So here's some preliminary results and a few notes:
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sub 1 finished patrolI ran the simulation a few times and compared results. Maximum deviation seems to be 1% with about 0.5% being more typical. I will increase the number of tests by a couple of orders of magnitude when I'm fully happy with all of it to reduce error. That will take a while to run though. There was a general trend for detection odds to go up with sub speed (multiple subspeeds not shown here) in a nonlinear fashion. For example, going from speed 0 to speed 1 might yield a 0.75% increase, but going from 15 to 16 might yield a 3% increase. There is certainly a point where decreased loiter time, causing a reduction in total targets to detect, will cut into total number of detection. I haven't done any math on this yet, but soon. With shipping going both ways, adding a north/south component to the patrol has decreased odds of detection in all cases with one unusual exception. The upright hourglass pattern has better odds of detecting targets with some of the games more close range sensors. I ran it 3 times to be sure it wasn't some kind of statistical anomaly. With the exception of a stationary submarine, Slower target speeds increase the odds of detection while faster target speeds decrease the odds of detection. Movment perpendicular to the targets course seems to increase the odds of detection up to a point. Past this point, such movement seems to decrease odds of detection. I need to do more data sifting to be sure, but I suspect that each sensor and sub speed combination has an optimum distance that this occurs. Without diagraming it, it would seem to have something to do with the rate at which a target can traverse an area you have just searched. (I.E. knowing where targets cannot be, as mentioned above) Quote:
Good posts though. |
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Doubt it can be fixed.
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