I must confess to some astonishment and disappointment at where this thread has gone since my posting (#156) two days ago. I had some other things I needed to do and hadn't looked at the forum. This morning, I looked at this thread and saw so many falsehoods, misconceptions, and ridiculous insinuations posted that I hardly know where to begin.

Let me start by trying once again to correct Gary's utter misconception of the whole tidal issue (which many seem to have swallowed hook, line and sinker).

In Post #158 Gary asked,

"*Thank you for the reef survey map, it is very illuminating. This brings up two questions, what is the height of point "a" compared to the tidal datum at Hull island and what is the relative height of the plane's location compared to point "a"?"*

The answer to the first part of Gary's question is - it doesn't matter.

As Bob has explained:

"The Hull Island tidal datum -- per se -- is irrelevant. What matters is how the tide height at a given point on the western reef of Niku varies with respect to the predicted/hindcast Hull Island tide.

There are two ways of approaching that problem.

(1) Put a tide gauge at every point of interest in the Electra landing area, and collect tide measurements at each gauge, then run a linear regression for each gauge against the Hull Tide corresponding to the time of each landing area gauge observation, to get the tide correction to be applied to a given Hull prediction/hindcast, to get the corresponding tide at the Niku location. That approach is obviously impractical because of the sheer on-reef labor involved, not to mention the personnel hazard involved in walking on the reef when the water depth is more than about 18 inches.

(2) Install a single gauge at a safe and convenient location -- the boat landing channel was chosen -- and read the tides there twice daily from the expedition ship's boat, then run a linear regression to get the conversion factor to find the landing channel gauge site height for any given Hull tide. To get the corresponding tide height at a point of interest in the Electra landing area, it would be necessary to know the height difference between the reef surface at the landing area and the reef surface at the boat landing channel gauge site. That was accomplished by your leveling survey, which had to be done in two phases, since the landing channel gauge site is not visible from the Electra landing area. Phase 1 -- with the SRX on the southwestern shoreline at a point with sight lines to both the NC wreckage and the landing channel gauge site -- measured the reef height difference between the landing channel gauge site and point A -- at the large tank in the NC wreckage. Phase 2 -- with the SRX on the shoreline east of the NC wreckage -- measured the reef surface heights of 18 points in the landing area relative to the height of point A.

Given the results, we can find the tide level at any of the surveyed points in the landing area for a given date/time by: (1) applying the regression correction factor to the Hull Island tide, to get the tide level at the landing channel gauge site; (2) applying the point A reef height differential relative to the channel gauge site height to get the tide height at point A; (3) applying the reef height differential for the landing area point of interest relative to the point A tide, to get the tide height at the point of interest. Of course, steps (2) and (3) are combined in practice.

We found that the reef surface height at point A is 0.21m lower than the at the channel gauge site, hence the tide level at point A is 0.21m higher than at the channel gauge site."

The answer to the second part of Gary's question is - we don't know because we don't know exactly where the plane was parked. If the plane was washed over the reef edge at or near the location of the Bevington Object, the plane was probably parked on the reef surface roughly 15 meters north and east of there. Bob Brandenburg has calculated the reef height in that area to be +.12 meters of Point A.

In Post #161 Gary said,

"*If TIGHAR no longer considers the Brandenburg study to be accurate then there should be another research paper on the site stating that the Brandenburg paper is no longer to be considered to be accurate, and why, and providing the new, more accurate, information. I haven't been able to find such a paper on the site, have you?"*

There is always tension between taking the time to do the work and finding the time to write up reports of the work. We think the former should take priority over the latter, consequently our research is typically months, and in some cases years, behind the published papers and bulletins. The Post-Loss Signals Catalog took twelve years to complete. Bob has been working for many months on a comprehensive paper on the whole issue of water levels on the reef and how they constrain what could and could not have happened. As soon as it’s finished I’ll review it and, after Bob and I have discussed any questions I have, we’ll put it up on the TIGHAR website.

In Post #163 Gary said,

*"Yep, that's what I am asking for, the new number that Ric is now using for the height of the reef. Ric's and Brandenburg's explanations in 2007 of how the height of the reef was determined made it appear that the new, 2007, data had been incorporated into the Brandenburg paper, there was certainly no indication given, at that time by either of them that it hadn't been. Now, five years later, it is claimed that Brandenburg's definitive study, that has been on the site for five years, is not accurate. I think you can see my point."*

The "definitive study" Gary refers to was written in 2006 (as it clearly says right at the top of the page - see for yourself) - so it obviously could not have incorporated the data from the reef survey done in 2007. Neither Bob Brandenburg nor I ever implied that it did. I pointed this error out to Gary in a previous posting but he persists in perpetrating fiction.

BTW, calling the 2006 computations of water level on the reef a "definitive study" is meaningless. Any study can do no more than present the situation as it appears, based upon the best available evidence at that time. No study can be definitive.

The reef height calculations used in Brandenburg's 2006 study were based on a preliminary survey done in 2003 by TIGHAR member Howard Alldred. Howard was a geologist from New Zealand who had considerable familiarity with coral reefs. He participated in the 2003 expedition which spent only a few days at the island and had minimal equipment, so Howard was only able to measure the angle at which the reef slopes toward the ocean in the vicinity of Norwich City. Sadly, Howard died of brain cancer a couple years later. Bob Brandenburg used Howard's slope angle to calculate water depth at the then-presumed landing location on the assumption that the slope was uniform all along the reef. That’s where the figures in the 2006 paper came from. The detailed reef survey done in 2007 showed the assumption that the slope was uniform to be incorrect and gave us much better information about the reef height in various places around and north of Norwich City.

On this thread, Gary’s persistently mistaken allegation that the 2006 study was based on the 2007 survey led to the bizarre notion that I had somehow come up with “new numbers” that I preferred to Bob’s numbers and had used them to make the tidal graph that was attached to Post #143. The graph was made by Bob, not me. It’s the latest in an evolving set of graphics we use to evaluate and illustrate the results of our research into water levels on the reef. We’ve had to change the graphs several times as our understanding of where the plane probably was has changed based on new information. I don’t want to publish the full set until we’re as sure as we can be that we have it right.

What I find most disturbing is the ease with which Gary’s transparently misinformed attack caused some to not only doubt the entire Niku hypothesis but to question my ethics as well.