The all seeing eye of Glen

[ChezDaJez]

ORIGINAL: el cid again

The formula for the theoretical visual horizon is: 1.23 X SQRT(altitude in feet). So a plane flying at 500 feet has a visual horizon of 27.5 nm. But that is the theoretical range. The actual practical range is probably half that.

This is incorrect - in the sense the formula cannot be right - it is a useful rule of thumb for close in ranges. The USN does not teach this in this way - they make you memorize points in the function - and how to know where these points are.

News flash: The Earth is almost a sphere (very little distortion). So a linear function of altitude will not yield range. In fact, as you gain altitude, you gain range much faster than at a linear rate.

As a radar and countermeasures guy I got to do this sort of thing a good deal - because radar signals are almost like light (they actually bend slightly in some cases - but we pretend they are like light even then).
Further, I would always track everything in my neighborhood, by every means possible. I would have radar plot a track and then see if I (or an operator) could track entirely WITHOUT radar - single station passive detection INCLUDING ranging. To do that I had to use a German formula (published in a US technical intelligence document) which permits you to calculate range for altitude of the emitter (= observer if visual). I got to the point I could track an aircraft WITHOUT using radar and be within 10% of its real range - doing the calculations in my head in an era before calculators or computers like we have now. So trust me on this: the function is wrong. The earth really is curved, and range is not a linear function of observer altitude.

NEWS FLASH! Reread my post. We're talking visual horizon here. You know! That point where an object can no longer be seen due to the curvature of the earth! What the formula defines is a visual or radar SURFACE footprint from a given point of altitude. I said that the formula applied to determing the theoretical visual horizon, not omnidirectional range. And yes, the USN does teach this. Its where I learned it. It also applies to the radar horizon with a slight midification. I still have many of my training materials (the unclassified ones) from my A school. The Line of sight and radar horizons are virtually the same, the difference being you use 1.23 for LOS and 1.5 for radar. A fairly insignificant diifference.

A one hundred foot altitude yields a theoretical visual horizon of 12.3 nm. A 1000 foot altitude yields a theoretical visual horizon of 38.9nm. In case you don't understand what a theoretical visual horizon is, it is the maximum theoretical distance that an observer can see an object floating on the surface of the sea. If that object has height, for example it has a 100 foot mast, then add the two visual horizons together. If both are at 100 foot altitude, the maximum theoretical visual detection range is 24.6nm. This formula obviously does not take into account the size of the object to be detected. Its going to be much easier to detect a battleship than a periscope at those ranges.

So trust me on this: the function is correct. Range to the horizon is most certainly a linear function of observer altitude and is only limited by the curvature of the earth.

"single station passive detection INCLUDING ranging"

I assume you are using ESM as you used the term emitter. Exactly how are you computing the altitude and range if angle above the horizon and emitter power levels aren't known? Even if they were known, a good airborne radar operator can spoof the techique by varying output power or varying antenna tilt. Seems to me it mustn't have been very effective as the Navy doesn't teach this "ESP technique" to its AW operators.

Read my credentials at the bottom. I was an Aviation Warfare Electronics Operator for 26 years and am intimately familiar with airborne passive and active acoustic systems, radar (traditional and ISAR), ESM, MAD, IFF and IRDS. BTW, we're also taught to compute doppler, AOB and TMA values in our heads. I've also spent many a flight hour with my head pressed against the bubble observer windows in the P-3 searching for air and surface contacts in all kinds of weather conditions throughout the world.

So trust me once again here, I'm on very solid ground with this one.

Chez

[spence]

Oh come on now Chez

Cid is quoting top secret data compiled by the Japanese in 1066BC and currently held under extremely heavy guard under a mountain in North Korea; right next to the stockpile of captured Japanese Thorium bombs I believe.

[ChezDaJez]

ORIGINAL: el cid again

An observer looking up sun may only have an effective visual range of 2-3 miles while the observer on the other side of the aircraft may be able to see 8-10 miles.

US Navy teaches a SURFACE observer (not even on the masthead) has 100% visibility for 8 nautical (not statute) miles. If you really only can see ships at 8-10 miles from an airplane - you are not doing as well as real observers can from the masthead.

For a sense of actual line of sight distances, go look at a very high frequency surface search radar. For practial purposes, its beams travel line of sight. You will spot every ship within 16 nautical miles, and probably even periscopes and rafts within 8, unless it is rough weather.
You will spot large ships well in excess of 30 nautical miles - and I have seen islands with mountains at 75. IF surface search radar can see it - I can take you outside and put glasses on that bearing - and you will see it too - unless inhibited by fog or haze. If you are trained in diligent human visual search technique, you will spot the target without knowing it was there, from the radar. This mattered to me - I like to sail with radar OFF - because a smart enemy listens for radar signals. And even with it on - I wanted backup detection: the radar can go down - or be a casualty - or not be able to see a small target - like a missile head on. I trained observers to spot the missile too small for radar detection - and I expect observers so trained to report. I don't leave it to change - I make them practice.

Why do you keep referring to radar? My point is visual search! Looking up sun on a very bright day is a good way to fry your eyeballs even with the best set of polarizing sunglasses (which of course the navy doesn't provide) in an extremely short time. Even looking down sun on a bright day from altitude can lead to glare blindness in all but the calmest of seas from sun reflections off wave action. There is a huge difference in the amount of reflected glare received by a ship at sea level and an aircraft flying at 3000-5000 feet (optimum search altitude).

In the P-3, we seldom used radar. The majority of our missions were covert, EMCON Alpha, so we had to maintain a visual lookout. We rotated observers every 15-20 minutes to keep a fresh set of eyeballs in the windows.

As far as visually spotting a missile headon, all that does is give a lookout a chance to duck. Its already too late to engage with manual systems. Maximum radar detection range (radar @ 100 ft alt, missile at 6 ft) is about 18nm for a sea skimmer. Assuming a velocity of 600kts, that's about 1.8 minutes until impact. Maximum visual detection range for an observer at 60 feet is about 12.5nm. That's about 75 seconds until impact. Real life experience (Stark and Sheffield) tells us the actual detection range is considerably less, more on the order of 4nm or so. I don't care how well trained a lookout out is, there is a human limit to detecting a small object. Spotting a 13-14 inch diameter missile is a near impossible task at maximum theoretical visual range.

Look at the real life examples we have. How much time did the Stark have? 10-20 seconds or so? And this was with a fully alerted ship with all systems operational and in use (except CIWS which was in standby) and an AWACS overhead to boot.
What about HMS Sheffield? She had about the same amount of time to react. Detecting a missile visually is basically giving someone enough time to say, "At least I know what hit me!"

Chez

[ChezDaJez]

Oh come on now Chez

Cid is quoting top secret data compiled by the Japanese in 1066BC and currently held under extremely heavy guard under a mountain in North Korea; right next to the stockpile of captured Japanese Thorium bombs I believe.

Damn, I gotta go lock the door. The FBI might be coming for me![:D][:D]

Chez

[Kwik E Mart]

ooooh! mathematical-theory-versus-real-versus-approximation cat fight! *hiss, hiss, spit, reowwwww!!!*

this is why us pilots never argued with the jezebels in the P-3...jezebel starts spewing formulas...the pilot's ears start bleeding...pilot looks over to co-pilot and rolls his eyes...TACCO and navigator start yelling at each other over which search pattern will work best...pilot tells the TACCO to relax, it's a clear day...fly another 5 miles in a random zig-zag pattern and flight engineer spots the contact over the rim of his coffee cup...pilot tells jezebel to go back to sleep until we need to do the next RIG...[;)]

[el cid again]

We're talking visual horizon here. You know! That point where an object can no longer be seen due to the curvature of the earth! What the formula defines is a visual or radar SURFACE footprint from a given point of altitude.

That is indeed what you advertised. And I said it isn't correct. It is false. The function is not linear. Because it isn't.

[el cid again]

A one hundred foot altitude yields a theoretical visual horizon of 12.3 nm.

Do you know what you are saying? You are saying you can see a thing on the surface - or the entire hull of a ship - at about that range. You can see mastheads three times as far. So how come you only see ships at "8-10 miles" from an airplane in the opposite direction of the sun?

[el cid again]

I assume you are using ESM as you used the term emitter. Exactly how are you computing the altitude and range if angle above the horizon and emitter power levels aren't known?

Ah! A techie guy. Well - seems those Germans were pretty clever. They had rules - and the rules still work today. It requires you know a bit about the emitter: even if you never saw it before you need to be able to say "that is a surface search radar" - something like that. If you have intel catalogs (we do) it works very well indeed - "that is the surface search radar used by Russian navy ships". Once you do that, you use logic! If it is a periscope radar, you assume the altitude is zero feet (logically enough). If it is a surface search radar on a ship you assume 100 feet (or whatever you believe the masthead to be - if signals indicate this is a really big warship - or even ID the class - you might know exactly). If it is an aircraft emitter, you guess - in the context of where you are - who it is or might be - and what is SOP. ["That is a P-3 Orion. It usually patrols at x,000 feet. We assume x,000 feet.] And so on.

[el cid again]

I've also spent many a flight hour with my head pressed against the bubble observer windows in the P-3 searching for air and surface contacts in all kinds of weather conditions throughout the world.

I believe you. And I salute you - I like P-3s and all other friendly patrol planes - and I am upset we have got rid of so many - and given the others so little patrol time no one may remember how do to it?

And I believe you are reporting correctly you cannot see at great ranges. But I did not train you. Meet me at an observatory (the fast way is to use the dome slit to help you - crib you - once you get the hang of it you can do it anywhere - and once it is a habit you do it easily).

This is not just theory: I train to WWII JAPANESE standards. It may not be quite as true for other navies, but we were much more diligent then than we are now. Today you really have a hard time getting a lookout to actually look, for four hours, doing a proper sector search.

[el cid again]

Why do you keep referring to radar? My point is visual search!

To quote you - they are near enough the same. In my day we got an extra 10% in certain bands - and Norman Friedman published this year they figure 15% with current surface search radars - but it is pretty nearly the same. At extreme range you have a hard time saying more than "I have something over there" anyway - you have to close the range or use signals or ask over the radio to ID it. Except if you have a really fancy toy - a side looking radar and a good back up set of data - you might be able to get a radar picture and computer ID - not a topic for my era - never mind WWII. But radar line of sight approximately equals visual line of sight. In practice theoretical radar detection range is often overstated by 5% anyway - so they are pretty close.

[el cid again]

How much time did the Stark have? 10-20 seconds or so? And this was with a fully alerted ship with all systems operational and in use (except CIWS which was in standby) and an AWACS overhead to boot.

1) In those days, AWACS could not talk to a USN ship. An old problem, it was not fixed until 1991 - and nearly was not fixed then. When USN and RAN ships (including USS Boston and HMAS Hobart) were attacked by USAF in June, 1968, there was no way to tell the planes "we are on your side." They "communicated" that by firing 5 inch guns!

2) Every system on USS Stark was down. Not one was even on standby or manned. Nor could ANY of the three different weapons bear on the primary threat axis. The ship had been in a hot (shooting) war zone - a war in which 80% of the missiles fired hit bouys - a clue they had no idea what they were shooting at - but the captain did not follow any reaonable policy at all. He even had allowed an engineering test illegal except far in the open ocean - that is against regulations - so he was not able to maneuver at full capability.

3) WITHOUT the fine systems on board Stark we defeated every ASCM attack from 1968 to 1972. But we did not do it by not manning our systems. And we did believe that visual detection could work if we faced non-radar guided missiles (which of course broadcast "I am coming from this direction").

[el cid again]

As far as visually spotting a missile headon, all that does is give a lookout a chance to duck. Its already too late to engage with manual systems.

Except it isn't. Probably the best real world example is a 1973 war with Israel in which 54 out of 54 ASCMs were detected and engaged. Not one vessel in IDF had SAMs - they got them every one with countermeasures or guns (mainly the very fine 76mm Compact - which we eventually adopted in spite of "not invented here" Pentagon politics). There were several cases where lookouts spotted the threat first. In such a case you are better off than not having a few more seconds.

And there is something else: often all you have is enough time to broadcast a warning over the 1MC (announcing system for non USN types). That matters. It GREATLY reduces injury if sailors are braced for a shock and not doing something that can turn out badly when it comes. But if you have a fully manned and ready countermeasures station, it should be enough time to launch countermeasures rockets, and to turn on a jammer. Without saying too much - a USN jammer does not need to be set on a frequency - it takes the hostile signal and amplifies it - sending it back - whatever it may be - so it is always on frequency - instantly - faster than you could ever set it. All you do is turn it on. Now I don't know about you - but I hear "missile inbound" I turn on the jammer. I know it is against international law - that only the captain can authorize jamming in peacetime - but

1) If we are under fire I consider it a technical state of war
2) I had a deal - and I always insist on it - "If I 'recommend' jamming you have to 'approve' - because I already have turned the jammer on."
If the captain does not agree, I won't take the watch.

[ChezDaJez]

this is why us pilots never argued with the jezebels in the P-3...jezebel starts spewing formulas...the pilot's ears start bleeding...pilot looks over to co-pilot and rolls his eyes...TACCO and navigator start yelling at each other over which search pattern will work best...pilot tells the TACCO to relax, it's a clear day...fly another 5 miles in a random zig-zag pattern and flight engineer spots the contact over the rim of his coffee cup...pilot tells jezebel to go back to sleep until we need to do the next RIG...

That is the great paradox of the P-3 Navy. The one guy whose eyeballs are supposed to be focused on round dials INSIDE the cockpit is the one who always spots the target first! It must be the bloodshot eyes of the FE that filters out all that glare!

And what do you mean sleep? What Jez guy ever slept on a P-3? Don't answer that!

"What's that? Set 4? Come on SS2, hurry it up! Damn, when's flight gonna Set 3? Cool! 3's set, now I can smoke while we check the gear. Condition 3 check complete, Tacco. Kilo Alpha. Hey, SS2, wake me when we're onstation. Don't forget the coffee. ZZZzzzZZZzzz." [:D][:D][:D]

Chez

[barbarrossa]

ORIGINAL: el cid again



2) Every system on USS Stark was down. Not one was even on standby or manned. Nor could ANY of the three different weapons bear on the primary threat axis. The ship had been in a hot (shooting) war zone - a war in which 80% of the missiles fired hit bouys - a clue they had no idea what they were shooting at - but the captain did not follow any reaonable policy at all. He even had allowed an engineering test illegal except far in the open ocean - that is against regulations - so he was not able to maneuver at full capability.

During Desert Storm our engineers were practicing for EMAT that was going to be performed on the way home.

This included dropping the load and bringing everything including all radars down. As any electronic tech knows -- stuff is more likely to break turning it off and turning it on.

It used to drive me crazy as an FC. Here we are in a shooting war practicing for a cheeseball damn eval. I used to ask......hey, shouldn't we like survive the war then worry about the b.s. later?[X(]

[Brady]

Aparently the I-8 made great use of her Glen to spot Merchant shiping, and did some prety ruthless things to the merchantmen.:

http://www.combinedfleet.com/I-8.htm

[Charles2222]

ORIGINAL: Mike Scholl

ORIGINAL: Charles_22

ORIGINAL: Grotius

Thanks for those TROMs, Brady. They do show pretty active Glen recon missions -- but maybe not so much "Naval Search" as it's modeled in WITP. I mean, mostly the logs show Glens dispatched to recon particular targets: PH, Noumea, Santa Cruz Island, etc. Obviously a Glen would report any enemy vessel it saw on the way to the target, but you don't see many instances of a Glen reporting a contact in the open ocean, do you?

The point of contention here isn't that the Glen should have it's powers limited, but that they weren't hardly used and unreliable, or that they could only be used in the calmest seas. The issue of 'no search' only comes up not because they can't do it IRL, but because it gives them lots of power they shouldn't have in the game, because of the bias against their being used beyond the slightest degree because of alleged lack of use. If a plane can recon a port, something often more imminently dangerous than spotting ships at sea, then surely it can spot fleets. Whether the IJN used them very much in that role is immaterial, as the new commander should have that basic option. Of course there's always the possibility of getting a toggle option for these who quiver at the sight of the mighty plane spotting fleets. Any plane that can recon a port, and was used int hat role, should surely be able to search for a fleet.

I hope I'm not opening up on you Grotius when I say this, but it really does make me ill that it seems that virtually every capability of IJ in this game in being called into question that such-and-such capability shouldn't be granted to them because we don't have extensive documentation of it's being done. Besides that point, since we already know that the IJN was often using it's subs, even non-Glen ones for reconnning the sea, just why would they not use the Glen for navy searches when they're just as capable of that as a float plane?

Good point Charles. I would really like to see those who speak in favor of the Glen produce some real life examples where it was used to hunt down shipping at sea. (And no, one or two times in 4 years doesn't count.) If it's to be a usable "game mechanic", it needs to have been used IRL on a regular basis as well. As far as I can tell, sub-launched floatplanes were used almost exclusively for "niusance raids". Even in the period before Midway, the Japanese didn't try to arrainge for some of their subs to launch floatplanes to scout PH for the US CV's. Instead they tried to use one to refuel a Flying Boat for the mission. The game makes the Glen into a useful weapon, but the Japanese could not.

Try reading those documents which I think it was Brady provided. While you may only respect regularity in using weapons in this game, then that damns you to gutting the A-bombs too. There is no need for only things that are regular in the game, rather that all things, irregular or not, are treated as they should. From what you write, I'm beginning to think that you think people are attacking ships with those things. If so, I haven't seen that in this thread, and considering how any plane can carry an ordinance of some sort, even if just MG's, then certainly people should be able to use them. I just don't see why the big, bad Allied side can't put up with some sort of IJ intelligence, as reconning a base isn't much different from reconning a set amount of ocean, and, like I said, all subs could do recon anyway. Even if the Glen wasn't used to search fleets out so well, then since the game denies subs the ability of doing any recon (apart from attacking them), which anyone who has spent any time reading up on IJN subs would know they did, this use of Glens shouldn't be so hard felt.

[Charles2222]

ORIGINAL: Grotius

ORIGINAL: Charles_22
I hope I'm not opening up on you Grotius when I say this, but it really does make me ill that it seems that virtually every capability of IJ in this game in being called into question that such-and-such capability shouldn't be granted to them because we don't have extensive documentation of it's being done.

No worries, I enjoy reasoned and civilized discussion of an issue, and your post certainly qualifies as that. For what it's worth, I've played the IJN four or five times in PBEM, and the Allies once, and I've often posted on what I see as the ahistorical massing of Allied air power very early in the game. So I hardly "have it in" for the IJN. But it was striking to me that the logs Brady posted described recon missions only, and not once reported that a Glen spotted such-and-such vessel in the open sea. Sure, that doesn't mean that Glens weren't used in the air-search role -- but it might well suggest that Glens weren't very effective in that role. Why would the logs tell us the Glen spotted a vessel in such-and-such harbor but would omit telling us about the Glen sotting a vessel in the open sea? Then again, my concern may be a broader one -- that air search is still too effective in WITP, even after having been toned down as compared to Uncommon Valor.

As for the Pete, there's nothing to complain about -- it's pretty useless, isn't it?

Yes, I did think you were with the good guys at one time[:D] That's alright, if I ever get around to even playing 50% of the campaign as the IJN, I will one day become a turncoat too. I wasn't so much pointing out anything in you in particular, but just this rampant wave that seems to be going on where the IJN has weapons to use as we want, but then somebody keeps coming along and wants great documentation on them using something in that way. I made an earlier comment that if regularity is the basis of being able to use systems then surely the A-bombs must not be able to be used either (although it has slight [:D] documentation).

[el cid again]

Good point Charles. I would really like to see those who speak in favor of the Glen produce some real life examples where it was used to hunt down shipping at sea.

Try reading Advance Force Pearl Harbor.

Advance Force is the formal IJN term for the main body of the 6th Fleet (submarines) - which was to be the advance scouts for the Kiddo Butai - and also which was to follow up and sink cripples. [This actually happened at Midway - a place where not much went right for IJN doctrine: the USS Yorktown was ordered sunk by a single submarine - and she did just that.] Anyway, the Advance Force history is very detailed, and does include Glen use in the wide body of the Pacific between the US and Hawaii - in addition to the successful recon of Pearl itself both before and after the raid (complete with photographys). It is not well understood - because of the date of the attack - but the advance force is the only part of the Pearl Harbor striking force which hit a primary target - an aircraft carrier. Burl (Burlingame) doesn't miss it though - he is curator of the aviation museum on Oahu and used to thinking about history.

[Kwik E Mart]

ORIGINAL: ChezDaJez

this is why us pilots never argued with the jezebels in the P-3...jezebel starts spewing formulas...the pilot's ears start bleeding...pilot looks over to co-pilot and rolls his eyes...TACCO and navigator start yelling at each other over which search pattern will work best...pilot tells the TACCO to relax, it's a clear day...fly another 5 miles in a random zig-zag pattern and flight engineer spots the contact over the rim of his coffee cup...pilot tells jezebel to go back to sleep until we need to do the next RIG...

That is the great paradox of the P-3 Navy. The one guy whose eyeballs are supposed to be focused on round dials INSIDE the cockpit is the one who always spots the target first! It must be the bloodshot eyes of the FE that filters out all that glare!

And what do you mean sleep? What Jez guy ever slept on a P-3? Don't answer that!

"What's that? Set 4? Come on SS2, hurry it up! Damn, when's flight gonna Set 3? Cool! 3's set, now I can smoke while we check the gear. Condition 3 check complete, Tacco. Kilo Alpha. Hey, SS2, wake me when we're onstation. Don't forget the coffee. ZZZzzzZZZzzz." [:D][:D][:D]

Chez

you picked on the poor SS2 for coffee? my jez always yelled at the AO or the IFT for coffee...maybe because sensor 2 was always putting on his poopy suit for "practice" for the crusty sensor 1 [:D]

[ChezDaJez]

you picked on the poor SS2 for coffee? my jez always yelled at the AO or the IFT for coffee...maybe because sensor 2 was always putting on his poopy suit for "practice" for the crusty sensor 1

What else were SS2s good for besides carrying tapes? Besides both my Ord and IFT were bigger than me![:D]

Chez