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Author Topic: The Dole Derby  (Read 121982 times)

Harry Howe, Jr.

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Re: The Dole Derby
« Reply #180 on: March 25, 2012, 02:30:07 PM »


In common speech the term reductio ad absurdum refers to anything pushed to absurd extremes.

Nuff said.
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Harry Howe, Jr.

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Re: The Dole Derby
« Reply #181 on: March 25, 2012, 04:21:52 PM »


Gary
"Now you follow the same procedure, you continue a bit further, turn around and then paddle in the opposite direction against the current. What will the time be on this up current leg to pass the bobber?"

3mph - 1mph=2 mph(2.93 ft/sec)   18 ft/2.93=6.14 seconds.

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Gary LaPook

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Re: The Dole Derby
« Reply #182 on: March 26, 2012, 12:59:11 AM »


Gary
"Now you follow the same procedure, you continue a bit further, turn around and then paddle in the opposite direction against the current. What will the time be on this up current leg to pass the bobber?"

3mph - 1mph=2 mph(2.93 ft/sec)   18 ft/2.93=6.14 seconds.

I was expecting, Harry, that the example I gave would get you to recognize the error in this computation but you missed the opportunity. I wrote before:

"Now let's consider a case where there is a current. Same 18 foot canoe and procedure, only this time you have a 1 mph current moving in the direction of the first test run, you are traveling with the current on the first pass by the bobber. Since you are traveling with the current your speed is now 4 mph, 6 feet per second, so you pass the bobber in 3 seconds. Now you follow the same procedure, you continue a bit further, turn around and then paddle in the opposite direction against the current. What will the time be on this up current leg to pass the bobber?"

You have been doing the math as though the bobber were fixed to the bottom and not free to move with the current or using a landmark on shore as your reference point. But the method you gave to determine the current, that started this discussion, was to time the movement of the raft past a piece of jetsam that certainly was not fixed to the bottom of the ocean so was free to move with any current. Using my canoe example, with the canoe going with a 1 mph current, its speed over the bottom would be 4 mph. But the bobber would also be moving with the current and so was also moving with the current at 1 mph over the bottom so the relative speed between the canoe and  the bobber is still only 3 mph, the speed that you are paddling the canoe through the water so the time would have been the same as in the example given with no current, 4 seconds not the 3 seconds I gave in the current example that I thought would tip you off to the problem in your original statement.

The answer to the test question "What will the time be on this up current leg to pass the bobber?" is the same 4 seconds because the relative speed between the canoe and the bobber will still be 3 mph. It works out like this, the canoe is going at 3 mph through the water against the 1 mph current so its speed over the bottom is only 2 mph in the upstream direction. The bobber is still moving downstream with the current at 1 mph over the bottom in the downstream direction. Putting these two speeds over the bottom together you find that the relative speed between the bobber and the canoe is still 3 mph so the time will still be 4 secends.

You can work out other examples for yourself and draw diagrams if necessary and you will find that the time to pass the bobber remains exactly the same no matter what the current is so it is impossible to determine the current using the method you gave.

gl
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Erik

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Re: The Dole Derby
« Reply #183 on: March 26, 2012, 08:17:20 AM »


Found this today in the news, Tsunami-tossed boat spotted off western Canada.

Although not related to the topic, I thought it was interesting none the less.

Interesting....

Here's another article I found.  It certainly adds to this thread's whole point that the Pacific ocean was not as desolate as we might think.

The Meriden Daily Journal; Oct 7, 1937
WASHING ASHORE OF RAFT REOPENS EARHART PUZZLE
"Deflated Rubber Life Boat Tossed up On Hawaii Island"

It's also curious to note that the article indicates Air Cruisers, Inc. of Hommondsport, N.Y. constructe the life raft for Amelia Earhart.  Interesting.... Any truth to that?
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Harry Howe, Jr.

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Re: The Dole Derby
« Reply #184 on: March 26, 2012, 05:35:01 PM »


Gary
Yeh, I didn't have my brain plugged in.  Was treating the bobber as a fixed frame of reference and of course it was moving with whatever current was flowing.   Shall I grovel?  LOL

Grovel, grovel, grovel.
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Gary LaPook

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Re: The Dole Derby
« Reply #185 on: March 26, 2012, 06:24:31 PM »


Gary
Yeh, I didn't have my brain plugged in.  Was treating the bobber as a fixed frame of reference and of course it was moving with whatever current was flowing.   Shall I grovel?  LOL

Grovel, grovel, grovel.

I was just hoping you would catch my hint. LOL

gl
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Jeff Victor Hayden

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Re: The Dole Derby
« Reply #186 on: March 27, 2012, 10:52:25 AM »

Gary, I understand you're the chap to speak to regarding navigation etc... If they did ditch and sink, in which general area would you expect it to have occurred in your opinion?

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Jeff Palshook

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Re: The Dole Derby
« Reply #187 on: March 29, 2012, 07:32:12 PM »

Jeff Hayden,

I don't mean to take away Gary LaPook's opportunity to respond in his own way to your question, should he choose to do so.  However, I note that Gary answered basically the same question you asked above in one of his posts several months ago.  Look at "Celestial Choir" section, "Noonan Navigation Error" thread, Reply #95.  Look in the second paragraph after the image Gary posted in that reply.

Gary took considerable flak here on the forum around Christmas time for declining to post his version of how he believes the Lae-Howland flight ended.  You can see from the referenced posting that Gary really had posted his "theory" in the recent past.
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Gary LaPook

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Re: The Dole Derby
« Reply #188 on: March 29, 2012, 10:00:43 PM »

Jeff Hayden,

I don't mean to take away Gary LaPook's opportunity to respond in his own way to your question, should he choose to do so.  However, I note that Gary answered basically the same question you asked above in one of his posts several months ago.  Look at "Celestial Choir" section, "Noonan Navigation Error" thread, Reply #95.  Look in the second paragraph after the image Gary posted in that reply.

Gary took considerable flak here on the forum around Christmas time for declining to post his version of how he believes the Lae-Howland flight ended.  You can see from the referenced posting that Gary really had posted his "theory" in the recent past.
Here is a link to that prior post of mine. When you read what I had written there then you will see that I was not real satisfied with that explanation and only settled on it as the "least bad" explanation. It's hard to believe, since I have been working on this problem for more than ten years, but I think I have come up with a better explanation in just the last day. I have to do some more computations and plotting to see if it works out, as I expect it will, before I put it out there for some more ridicule. :P I will also have to draw a number of diagrams and explain some more aspects of celestial navigation to make it understandable so it will take me a bit of time to put it together.

gl
« Last Edit: March 29, 2012, 10:30:50 PM by Gary LaPook »
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Heath Smith

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Re: The Dole Derby
« Reply #189 on: March 30, 2012, 03:51:55 AM »


I am looking forward to seeing your new theory Gary. When might we expect to see it?
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Jeff Victor Hayden

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Re: The Dole Derby
« Reply #190 on: March 30, 2012, 05:19:41 AM »

Not being an 'expert' in navigation I read all the posts you guys put up here in complete amazement. Having always been 'self loading cargo' as the RAF called us we always left the drop zone finding to the guys sitting sitting up front and, just jumped when they told us we were there.
Having read Garys possible explanations re: crash and sink in the vicinity of Howland there seems to be a lot of logic and common sense involved in this possibility. There's also many 'what ifs' but, that doesn't mean it isn't plausible. For example even if FN did manage to get a fix in the clear area to the south of Howland they might not have had enough fuel left to be able to make use of their newly found position.
Interesting to note though is that one of the two 'possible' contacts discovered by the Waitt Institute in 2009 was in fact to the south of Howland. Dismissed as being airplane but, hey, it's their money.
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Jeff Victor Hayden

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Re: The Dole Derby
« Reply #191 on: April 03, 2012, 05:14:09 AM »

Quote
It's hard to believe, since I have been working on this problem for more than ten years, but I think I have come up with a better explanation in just the last day. I have to do some more computations and plotting to see if it works out, as I expect it will, before I put it out there for some more ridicule. I will also have to draw a number of diagrams and explain some more aspects of celestial navigation to make it understandable so it will take me a bit of time to put it together.

Gary, I always have great respect for your navigational abilities and flight endurance knowledge so, look forward to seeing what you will come up with. Myself, I don't like to put all my eggs in one basket so therefore have an open mind as to what actually happened. There are 2 likely scenarios, the crash/ditch and sink versus the reef landing from what I can gather. Exclude Japanese prisoners,spys, gold runners etc... as pure Hollywood fantasy you are left with the 2 scenarios.
At this point I would say that BOTH scenarios have possible targets worth a second look. Now we know the general location of one of these possible targets, the Niku reef. The other possible target, within 60 Nm +/- 10 of Howland  will hopefully will sit somewhere in the area that you are working on.
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Gary LaPook

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Re: The Dole Derby
« Reply #192 on: April 04, 2012, 05:11:39 AM »


Dunno.  But the Colorado's logs include hourly postings throughtout the 2000 mile journey.  Most of the logs indicate ranges from NNE to SSE, all 'westerly'.  There are no readings that indicate 'easterly' flow.

Here is a sample.

What method did they use to measure the current every hour while underway? Did they have some device on the ship that could read out current? 

gl
« Last Edit: April 05, 2012, 02:57:00 AM by Gary LaPook »
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JNev

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Re: The Dole Derby
« Reply #193 on: April 06, 2012, 04:57:51 PM »


Dunno.  But the Colorado's logs include hourly postings throughtout the 2000 mile journey.  Most of the logs indicate ranges from NNE to SSE, all 'westerly'.  There are no readings that indicate 'easterly' flow.

Here is a sample.

What method did they use to measure the current every hour while underway? Did they have some device on the ship that could read out current? 

gl

The human navigator - but what he would have had to derive it from would be wanting, IMHO.

The log recorded sea state - height and direction of swells - which are of course surface observations; the log also captured surface speed in the form of 'revs' and 'log' - some inference could be made from that and drift, I suppose, but that's a bit sporty unless in a steady, strong current.  I believe truly measuring 'current' per se is much more subtly intricate than that and not particularly part of ship navigation in the open sea, but if anyone knows otherwise I'll be glad to know it. 

I don't think Colorado would have had a particular way to truly estimate currents except in a gross sense if drift was obviously contrary to winds and ship's way was noticeably hampered or aided, etc.  Current would have to be an obvious factor for there to be much measurement - otherwise it's probably mostly lost in the wash of normal surface navigation. 

We have ships going up and down the Savannah River here constantly - close to to a 20 mile passage to the sea - and currents are obvious there, for example.  Likely not so much on the open ocean in most places of the world unless well known to mariners already, like the Gulf Stream, a northerly coastal flow that is well offshore here.

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Gary LaPook

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Re: The Dole Derby
« Reply #194 on: April 06, 2012, 08:32:46 PM »


Dunno.  But the Colorado's logs include hourly postings throughtout the 2000 mile journey.  Most of the logs indicate ranges from NNE to SSE, all 'westerly'.  There are no readings that indicate 'easterly' flow.

Here is a sample.


Sorry Eric, but you are reading the Colorado log wrong. The last two columns refer to "swells" or "sea condition" not to current. Read the headings of those last two columns, at the very top is says "Sea" then the left one is "Condition" and the right one is "Swells from." The numbers you find in the left column code the shape of the swells and the second column shows the direction from which the swells are coming. None of this provides any information about the actual movement of the water, the current. I have attached the page from the weather code book which relates to sea condition. The numbers that you interpreted in your attached excerpt of the Colorado log as  currents of two or three knots are actually a description of the swells observed from the deck of the Colorado. You are never going to find a current of three knots in the center of an ocean basin. The only place you find such current speeds is along a coast line, such as the gulf stream.

Current at sea has always been the "great unknown" in navigation and it was not possible to have continuous knowledge of the current until the advent of computerized LORAN C in the 1980s and now with GPS. To determine current you need to know your course and speed "over the bottom" which you compare with your course and speed through the water, and the difference is the current. This is the same problem that Harry was having in prior posts on this thread. Prior to LORAN and GPS, navigators could only get two fixes a day, at morning twilight and again at evening twilight. Any coordinates given for other times are by dead reckoning and you cannot determine current from a DR position. So twice a day the navigator can plot a fix and measure the distance and course between those two fixes and determine his speed over the bottom. From the log of courses steered and revolutions, or "turns," of the propeller (giving speed through the water) the navigator can plot a DR position. Measuring the direction from the DR to the last fix gives you the direction that the current is flowing and the distance between the DR and the fix, divided by the time between the two fixes, produces the speed of the current.

Flight navigators use the same method to determine the winds experienced in flight, see example of this here and Noonan mentioned using this method himself, see attached. (The "no wind position" is the same as the DR position.)

gl
« Last Edit: April 06, 2012, 09:00:56 PM by Gary LaPook »
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