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Author Topic: Course lines, speed lines, where's Howland, and... where did she go?  (Read 85859 times)

Gary LaPook

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #105 on: December 18, 2011, 12:16:37 PM »

But, what do you think happened, Gary?

Again you have offered up another critique - fine, it's an open forum.  And you've offered more references to your website, which is very interesting - thanks for that, I find much of interest there and it is very generous of you.

But I (and perhaps others) STILL don't get a real sense of WHAT you think happened (cohesive hypothesis).

It occurs to me that we TIGHAR forum participants may fall roughly into three essential categories:
1 - Those who for whatever reasons believe in the TIGHAR-Niku hypothesis
2 - Those who are interested and are exploring - some with little or no comment, others who venture in
3 - Those who are committed to a belief in an outcome that is other that the TIGHAR-Niku hypothesis

Nothing wrong with any of that, and Ric and Marty, among others, have repeatedly assured us of an open forum.  That is productive - and takes courage of conviction, by the way.

It also means challenges are viewed as healthy - and I agree with that.  But vigorous challenges that so consistently seek to refute someone else's point ought to be backed by an equally firm conviction of a different belief.  Do you really search for NR16020, or do you simply believe that TIGHAR's hypothesis must be dismantled for some reason?  I don't have any real fear of that.  It's too solid for too many reasons, and there can be no meaningful search without some form of a compass on where to look and what to look for - and too many of us are devoted to learning the full story one day. 

So I would be a fool to not respect other opinions - but I find those opinions most useful when there is real conviction behind them.  Then where would you have us search, Gary?  To keep ruminating over your points gives little, if any, direction.  Lots of great information on your site, by the way - most enjoyable and what you offer is very generous.  But if you'd spend so much time and effort trying to impeach the Niku hypothesis, what is it that you believe so passionately that could lead someone to think in an equally productive direction if they want to find NR16020 and what happened to AE and FN?   

So, I for one would like to know what you really think if you can share it.  I promise to respect it, as I think others here would as well.  Granted, with many of us you would have a lot to overcome - lots of facts, reasonable observations and painstaking field work of many years by some very respectable people.  But your opinions are respected and appreciated. 

Maybe it's partly a 'tone' issue, but maybe it's also about substance: time and again ideas are posted here only to have you tear at them as if a barrister fighting to keep a prince from an appointment with the gallows.  A time or two I've even caught myself wondering "who (WHAT) IS Gary defending, that it's so important to 'defeat' TIGHAR's and other's ideas so often?"  That's kind of silly - or is it?  'Tone' may suggest many things to a perspiring mind.  :D  But you have said to me in a recent response: "it's a big ocean" and implied 'stay tuned' - so I am piqued - maybe you are trying to put a hypothesis together.  Maybe others would agree with me that it would be good to see what convictions lie behind your theme of 'discussion' here.  Then we can respectfully critique your own ideas too.

By this thread we've reviewed the take-off and ventured into much that went afterward, and why.  We can probably agree that the take-off and eastward progress toward Howland did happen.  So how about the rest of the flight and outcome?  When can we see what you really have in mind?  Do you think there is a significant-other theory, or do you think trying to rationally derive a working theory to eventually find NR16020 and realize AE's and FN's fate is just non-sense? 

Probably time for a new thread, folks...

LTM -
I'm working up to it, so I will post it soon. I'm not being coy, I just have some preliminary stuff to put together.
gl
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Gary LaPook

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #106 on: December 18, 2011, 01:50:46 PM »

Gary,

I was looking over your links and found this one:

https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxmcmVkaWVub29uYW58Z3g6M2I5OTVhMWZmMmI4ZDFiZA&pli=1

---

Landfalls - The safest way to get to destination

Landfalls are of two types: course line landfalls and speed line landfalls.

Course Line Landfall

The easiest landfall to fly and things being equal, the most accurate. is the course line landfall.

1. Observe a celestial body that gives a course line, line of position. Plot it on your Mercator chart

2. Advance the line of position through destination parallel to the one you just plotted.

3. Fly directly to the line of position through destination and turn toward destination.

4. Stay on this line of position until another line of position shows you to be off course.

5. Then repeat the process. But stay on a line of position through destinatiun.  There is no ETA in a landfall other than your best known ground speed.

Speed Line Landfall

Because a course line is at times the more difficult type of line of position to observe, and because sometimes only speed lines are available, you will also fly a speed line landíall.

In this type of landfall fly definitely to one side of destination. When you reach the speed line through destination, turn and fly into destination.

---

It seems to me (with zero expertise in this area) that Course Line Landfall requires being able to measure some celestial body (Sun or stars). This would also imply (to me) that in order for Earhart to end up on the 337/157, they must have had a approach heading 90 degrees from the advanced line of position (Howland) and that they would have definitely had some celestial reference to use. Again, to me, this seems like a risky strategy in pre-dawn conditions, perhaps overcast, where you cannot be certain that you will find any reference. This approach only works assuming you have some reference correct?

The Speed Line Landfall on the other hand requires that you chose a point that is "definitely to one side of destination". This might be used when you may perhaps have only ground speed data that you have recorded since your last verified position correct?

So given the above advice, are we not just debating over the the degree of being "definitely to one side of destination" if a Speed Line Landfall was used?

Thanks in advance.
Good, I'm glad that you took the time to read that excerpt from the 1944 Navigator's Information File. You should also read the other references I posted such as Force Manual 51-40 (1951 and 1973) and Weems (1938) and other reference books available here. You can also read my analysis here. From your question I think a little more explanation might be helpful since that excerpt didn't cover some more basic stuff about celestial navigation.

A "course line" LOP is one that runs parallel to your course line (or nearly so) so when you plot it on your chart and compare it with the desired course line you can ascertain if you are on course or off to the left or to the right. Since LOPs plot at right angles to the azimuth to the celestial body, a course line LOP involves observing an object out on the wingtip (or nearly so) and after you do the computations the resulting LOP is parallel to your course line (or nearly so.)

A "speed line" LOP is one that plots across your course line at a ninety degree angle (or nearly so) and shows how much progress you have made towards your destination and this allows you to calculate your ground speed and estimate the time you should arrive at your destination. Or. more accurately, the time you will have flown far enough to reach your destination  since a "speed line" gives you  no information as to whether you are on the correct course to actually hit your destination, you may arrive at the correct distance but be far off to the side.

Since being on course is the most important part about finding the destination, and the exact time of arrival is less important, you must find a way to get on a "course line" that runs through the destination. If there is only one celestial object available for observation you must arrange it so that your final approach is on a course that puts the object out on the wingtip and so the resulting LOP is a "course line." This is the entire purpose of turning off to one side to then intercept an LOP that is a "course line" through the destination.

At night there are a myriad of celestial objects to observe so the "celestial landfall" procedure is used during the day when the only object available is the sun. From the time of sunrise until an hour later at Howland on July 2, 1937, the azimuth of the sun was 067° true. An LOP derived from observing the sun anytime within this one hour period results in the LOP running at right angles to that azimuth making the LOP run 157° and 337°. Noonan had no choice in the chosen course to use to approach Howland, it was dictated by the location of the sun, and they had no control over that. By turning off to the side of the direct course to Howland, when they determined that they had intercepted the LOP they then turned ninety degrees thereby putting the sun out on the wingtip and establishing themselves on the "course line" running through Howland. Noonan would then take additional observations of the sun to ensure they were staying on course to Howland.

Risky, sure, but that's all you've got before LORAN and GPS and this technique was the standard method used throughout WW2 for finding islands. But not as risky as a surface navigator might think, since you are usually on top of the clouds, and even if some clouds are above you they rarely prevent observations for long periods of time.
----------------------------------------------------------

Discussion continued on NR16020 end of the line - what happened? thread.
gl
« Last Edit: December 27, 2011, 10:39:13 PM by Gary LaPook »
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Gary LaPook

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #107 on: December 19, 2011, 11:19:06 PM »


Gary
5.  They flew the 200 or so miles on the LOP towards where they expected Howland to be, didn't spot it, radioed in "we must be on you...",  continued on the LOP for 20 to 30 minutes and still didn't spot it so they decided to return along the 337 to 157 course and after they travelled 20 to 30 minutes back to where they had expected Howland to be and still not spotting it radioed "running N and S on the line 157/337" and continued on to the Phoenix Island group (Gardiner?)

But what you are saying doesn't make any sense, You had then aim for a spot 200 miles south-southeast on the LOP on the assumption that the uncertainty, or possible error, in the DR approaches 200 miles. But, they could be off course either to the right or to the left of the the 200 mile offset position along the LOP that you aimed for, so they might actually have intercepted the LOP 200 miles further out to the south-southeast, a  total of 400 miles from Howland. You then have them turning left and flying 200 miles along the LOP to the spot where they expect Howland to be. You then have them flying only 44 to 66 miles further prior to turning around but they actually must fly an additional 200 miles to ensure that they have flown far enough to find Howland because of the possiblity that they actually intercepted 400 miles from Howland.
See: https://sites.google.com/site/fredienoonan/discussions/navigation-to-howland-island

gl
Harry, you never responded to my post.

gl
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Harry Howe, Jr.

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #108 on: December 20, 2011, 11:59:02 AM »


Gary
Sorry, my reply was the one that went off into the Aether.
Short version:
As they flew the course from Lae to the offset point, taking sightings, the potential drift error would get smaller as the distance remaining after each sighting was reduced.  Example, when they reached the halfway point (1200 miles) the error would be 120 miles as opposed to the 240 miles at the start.  I assumed that they had a sighting at 0300 hours Howland (1500 (GCT) when they were 400 miles (error 40miles) from the offset point.
They made their turn (Port) onto 157 to 337 and proceeded towards Howland expecting it to be 202 miles (90 minutes at 133 mph) on the LOP.  Arriving at the expected location of Howland and not spotting it, they continued on for 44 or 66 miles, covering the potential error.  Again not having spotted Howland they circled back and flew 337 to 157 towards the Phoenix Island Group.
The potential drift in that 202 miles could have been 20.2 miles and there might have been a 5 nm (5.75 sm) chart error so they might have been as much as 26sm to the west of Howland's true position.  Expecting to see Howland on their nose, it might have been as much as 26 sm off their starboard wing.  Could they have seen it?
No Worries Mates
LTM   Harry (TIGHAR #3244R)
 
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Gary LaPook

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #109 on: December 20, 2011, 06:47:05 PM »


Gary
My 0600 time (1800 GCT) was based on an estimate of 2400 sm from Lae to the midpoint of the distance between Howland and Gardiner on the 157/337 line at an estimated "ground" speed of 133.33 mph (400 miles in 3 hours), i.e. 18 hours for the trip to that point.

I'm not sure what time that would have been in the radio room, o530 I suppose.
In a prior post you said:
 "The 0614 radio transmission referring to "Am  200 miles out..." was AE reporting her 0600 position on her regularly scheduled 15 minutes after the hour contact."

You have also said that this was when they intercepted the LOP, 200 miles out. But the 0614 Itasca time log of the radio reception of "200 miles out" occurred at 1744 Z, 16 minutes prior to the time you say that they intercepted the LOP 200 miles south-southeast of Howland so it doesn't appear that your theory that they were reporting that interception can be correct.

gl
« Last Edit: December 20, 2011, 06:52:11 PM by Gary LaPook »
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Harry Howe, Jr.

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #110 on: December 20, 2011, 10:33:56 PM »


Gary
Yes, a good point and one that bothered me and for which I have no explanation.  I can only say that the 1800 GCT time was based on an assumption of distance and speed.  They might have arrived at 1730 GCT and reported it at 1744 GCT, 0614 Itasca, but that is just a guess.
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Gary LaPook

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #111 on: December 21, 2011, 12:54:21 AM »


Gary
Yes, a good point and one that bothered me and for which I have no explanation.  I can only say that the 1800 GCT time was based on an assumption of distance and speed.  They might have arrived at 1730 GCT and reported it at 1744 GCT, 0614 Itasca, but that is just a guess.
There are two problems with that. The first is that to go the 2400 SM that you estimated the distance to the 202 SM point on the LOP south-southeast of Howland in only 17.5 hours would have required a ground speed of 137 mph and, taking into account the 25 mph headwind component probably existing at the time, would have required an airspeed of 162 mph.

The second problem is one I pointed out to you a long time ago back in September.

See: https://tighar.org/smf/index.php/topic,452.msg5640.html#msg5640

and: https://tighar.org/smf/index.php/topic,452.msg5646.html#msg5646

Intercepting south-southeast of Howland adds extra distance to the flight. 202 SM out on the LOP where you think they intercepted is at 1° 53' south, 175° 28' west. According to Google Earth, the distance from Lae, located at 6° 44' south, 147° 00' east, to your interception spot is 2609 SM, not the 2400 miles that you calculated. If you work it with the law of cosines your get 2602 SM and if you use the normal navigators spherical trig formula, that I posted before, you get the most accurate distance, 2603 SM, 48 SM longer than the direct distance to Howland and 203 miles more than you figured. To cover 2603 SM in only 17.5 hours requires a ground speed of 149 mph and an airspeed 174 mph. To do it in 18 hours (missing the time to make the "200 miles out" report) would still require a ground speed of 145 mph and an airspeed of 170 mph. All of these values are very unlikely as are the numbers even using your inaccurate 2400 SM distance.

To illustrate again why the interception would have been made to the northwest, assuming the same 202 SM offset, the distance from Lae would have been only 2525 SM, 31 SM less than the direct course to Howland and 79 SM shorter than your route and saving more than a half hour of flying time.

gl
« Last Edit: December 21, 2011, 12:56:38 AM by Gary LaPook »
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richie conroy

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #112 on: December 21, 2011, 09:10:30 AM »



if they are on "157 337 LOP" N ES S

could this mean they are on the  LOP 157 337  headed E by S

like i have marked on this compass

We are an echo of the past


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Heath Smith

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #113 on: December 21, 2011, 09:31:34 AM »

Quote
To cover 2603 SM in only 17.5 hours requires a ground speed of 149 mph and an airspeed 174 mph.

Gary, could you please expound on the 25 mph difference between ground speed and air speed?

A few other questions if you do not mind:

Were accurate wind aloft measurements taken that day from the Itasca?

Did Earhart receive a report of the winds aloft before she departed Lae?

How did they take these measurements back in the day? Weather balloons?

Thank you in advance.
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Martin X. Moleski, SJ

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #114 on: December 21, 2011, 10:50:39 AM »



could this mean they are on the  LOP 157 337  headed E by S

Besides the explanation that John gave you ("ES" is shorthand for "AND"--sending only the "dits" from the Morse Code for "and"), it is impossible both to "run on the line" 157 337 AND also leave the line in an East by South direction. 

Randy Jacobson explains some details of the message in "Log Jam."

This is my effort to break all of the pieces apart and re-assemble them in a meaningful fashion:

"We are on the line 157 337. XX Will repeat message.  We will repeat this on 6210 kcs.  Wait."
 
 Received on 3105 kcs, voice quality A3, signal strength S5.
 
 "(?/ KHAQQ transmission: We are running on XX line."
 
 The "North ES South" phrase could be dropped in before or after the word "line."
 
 "We are running on [North and South] line."
 
 The alternative is better English and makes more sense: "We are running on [the] line, North and South."
 
 "Line" appears twice in the log.  First it is identified as "line 157 337."  Then Earhart says that they are "running on [the] line."

The Itasca operator listens on 6210 kcs, then transmits on 7500 kcs--in code that AE and FN could not understand!--"Heard you on 3105 kcs."
LTM,

           Marty
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Harry Howe, Jr.

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #115 on: December 21, 2011, 12:28:16 PM »


Gary
Thanks for the critique, two things:
1. Why would they fly a NNW offset? There's nothing up there (unless you include the Japanese mandated islands.

2. Let the leg from Lae to a NNW offset point be A, a leg of a triangle, and B the sffset distance be another leg of the triangle, and C the direct distance Lae to Howland be the hypotenuse.  How can the distance A plus B be less than C?

The speed difference between 159 and 162 is less than 2%.  A time increase of one-half hour in a trip of 22 hours is about 2.3%.  The Electra had a cruising speed capability of 190 mph and a never exceed speed of 202mph so they had plenty of margin to adjust their speed as they progressed along their course, taking sightings and comparing their progress with what they wanted in order to arrive at a LOP around sunrise , which I believe was 0547 Howland.
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Gary LaPook

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #116 on: December 21, 2011, 07:07:22 PM »


Gary
Thanks for the critique, two things:
1. Why would they fly a NNW offset? There's nothing up there (unless you include the Japanese mandated islands.

2. Let the leg from Lae to a NNW offset point be A, a leg of a triangle, and B the sffset distance be another leg of the triangle, and C the direct distance Lae to Howland be the hypotenuse.  How can the distance A plus B be less than C?

The speed difference between 159 and 162 is less than 2%.  A time increase of one-half hour in a trip of 22 hours is about 2.3%.  The Electra had a cruising speed capability of 190 mph and a never exceed speed of 202mph so they had plenty of margin to adjust their speed as they progressed along their course, taking sightings and comparing their progress with what they wanted in order to arrive at a LOP around sunrise , which I believe was 0547 Howland.
Harry, back in September I invited you do draw a diagram so that you would be able see that an intercept to the north-northwest was shorter than an intercept to the south-southeast but you apparently have not done so. See:

See: https://tighar.org/smf/index.php/topic,452.msg5640.html#msg5640

and: https://tighar.org/smf/index.php/topic,452.msg5646.html#msg5646

So to make it easy for you to see this, I am attaching two diagrams that I have drawn for you. Diagram "A" shows the course from Lae to Howland, 2556 SM long, and the courses to intercept points 202 SM out, both to the north-northwest and to the south-southeast. I exaggerated the angles between the course from Lae to Howland and the LOP for clarity. You should be able to see the answer to your question that the distance to the offset point to the north-northwest is shorter than the direct course to Howland and the distance to the other offset point is longer.

Diagram "B" is drawn to scale and you should still be able to see the difference in the two distances.

The reason to fly an offset to the north-northwest is to be able to find Howland, they have no interest in going anywhere else.

No they can't just go a lot faster just to meet your idea that they should intercept the LOP at sunrise, 202 SM out to the right. To go faster requires much more power, it increases as the cube of the airspeed, which then requires full rich mixture (you should know this) so the BSFC goes way up and the specific range goes way down. This means that you get much fewer miles per gallon so you can run out of fuel before you get to your destination.
There is no reason to try to keep to your schedule because you cannot take an accurate sextant reading from an airplane at the time of sunrise because the sun's altitude is actually below zero and the Pioneer octant does not have a scale below zero. Even if it did, Noonan still would not be able to take an accurate sextant observation until the sun was six degrees above horizontal because the tables Noonan was using did not provide correction factors for lower altitudes. It took about one-half hour for the sun to climb above six degrees. The optimum time to reach the LOP was about an hour after sunrise as this would allow about a half-hour period when the sun was high enough for observations so that Noonan could work out his ground speed and the ETA at the LOP.
See: https://sites.google.com/site/fredienoonan/discussions/the-myth-of-the-sunrise-lop

You can also work it out using the law of cosines.
Intercepting to the NNW:

C^2 = A^2 + B^2 -(2 AB cos c)
C^ = 2556^2 + 202 ^2 - ( 2 x 2556 x 202 x cos 79°)
C^ = 2556^2 + 202 ^2 - ( 2 x 2556 x 202 x 0.1908)
C^ = 6533136 + 40804 - ( 197033.948)
C^2 = 6376906.052
C = 2525.254

Intercepting to the SSE:

C^2 = A^2 + B^2 -(2 AB cos c)
C^ = 2556^2 + 202 ^2 - ( 2 x 2556 x 202 x cos 101°)
C^ = 2556^2 + 202 ^2 - ( 2 x 2556 x 202 x -0.1908)
C^ = 6533136 + 40804 + ( 197033.948)
C^2 = 6770973.948
C = 2602.11

The cosine of 101 degrees is a negative .1908 so the second term ends up being a plus which is why this intercept is longer.


gl
« Last Edit: December 21, 2011, 07:27:24 PM by Gary LaPook »
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Harry Howe, Jr.

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #117 on: December 21, 2011, 09:17:13 PM »


Gary
How nuch of an offset to the NNW do you think they flew to be sure of their turn direction when they arrived at the offset point? 
Whar do you think was the reason they missed Howland?
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Gary LaPook

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #118 on: December 21, 2011, 11:23:23 PM »

Quote
To cover 2603 SM in only 17.5 hours requires a ground speed of 149 mph and an airspeed 174 mph.

Gary, could you please expound on the 25 mph difference between ground speed and air speed?

A few other questions if you do not mind:

Were accurate wind aloft measurements taken that day from the Itasca?

Did Earhart receive a report of the winds aloft before she departed Lae?

How did they take these measurements back in the day? Weather balloons?

Thank you in advance.
Forcast:

"Winds east south east about twenty-five knots to Ontario then east to east north east about 20 knots to Howland."

See:

http://tighar.org/Projects/Earhart/Archives/Research/ResearchPapers/Worldflight/2ndattemptweather.html


See attached photos. The radiogram is the coded measured weather from Itasca mentioned in in the Tighar document.
Noonan measured 23 knots and it was reported by radio to Lae.
gl

« Last Edit: December 21, 2011, 11:30:38 PM by Gary LaPook »
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Heath Smith

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Re: Course lines, speed lines, where's Howland, and... where did she go?
« Reply #119 on: December 22, 2011, 08:22:09 AM »


Gary, Thank you for the detailed weather report information.
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