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    Re: Fw: Grounding of cruiser PORT ROYAL
    From: Lu Abel
    Date: 2009 Jul 22, 13:49 -0700
    Great detective work, Frank!

    Out of curiosity, what is the source of the chartlet you included?   Reason for my question is that the official NOAA chart of the region has slightly different hydrography (http://www.charts.noaa.gov/OnLineViewer/19369.shtml).    Not enough to have made a difference in the grounding (looks like the Port Royal just turned way too soon), but I did notice some differences.

    Lu

    frankreed{at}HistoricalAtlas.com wrote:
    I'm attaching my solution for the position of the Port Royal on the reef. The position is based primarily on composite2 which I posted in message 9144 (www.fer3.com/arc/m2.aspx?i=109144). It is also based on a photo taken from the airport. Originally, I didn't think the airport photos would be useful since there are so few identifiable features but after some poking around, I found one that showed some long buildings that I was able to identify in the general aviation area of the fiel. I've attached that photo here. There is another at the airport with some palm trees in the immediate foreground that suggested a location, but I wasn't sure until I figured out the second airport photo.
    
    Greg R. and I have been exchanging messages off-list about various possibilities for the vantage point of the photo showing the Matson container lot in the foreground. We were all over the place. Both of us independently thought that it must have been taken from up in the hills well to the east of downtown, but eventually after carefully checking small details in the immediate foreground of the image (a USCG station apparently), I was able to find the building and its approximate height, close to 300 feet above sea level. This photo and the sunset photo, combined in the composites of the earlier message, were taken from the same apartment building. The Sun was, as expected, extremely useful since it provided an excellent angular scale. Later, I found the "smoking gun" --the photos were taken by one professional photographer, Marco Garcia, who perhaps lives in that building and has taken at least one other shot looking northeast from the same rooftop. 
    
    The better photo from the airport has a very useful clue in addition to the long buildings. The Hawaiian Airlines plane taking off in the foreground is a Boeing 717 (Hawaiian does not fly any other aircraft in this family which originally goes back to the DC-9). That aircraft is about 125 feet long while the USS Port Royal is just about 4.5 times longer. In the photo, they have the same apparent size. Therefore, necessarily, the photographer was 4.5 times farther away from the P.R. than the 717. After figuring out which runway the aircraft is on/above and knowing already roughly where the P.R. was located, it was a straight-forward matter to deduce this photographer's location atop the parking garage to the north of the terminal. Those structures in the near foreground that look like roof dormers confused me for a long time. They appear to be quite close to the photographer, but it's an illusion. They're on the terminal building about halfway between the photographer's locat
    ion and the 717.
    
    All of the these photos are excellent examples of the compression of distance in telephoto images. The vessel "appears" much closer to us than it actually is. 
    
    My best position estimate for the tall radar mast on the P.R. is 21d 27' 50.0" N, 157d 55' 24.3" W. The tip of the bow was about 2.5" east of there while the stern was about 3.5" west of that point. The vessel was aligned nearly east-west possibly headed a few degrees south of east.
    
    In the attached map named "final-chart" there are two sets of three lines radiating from each photographer's location. The radiating lines extending from north to south show the direction to the P.R. and the extreme left and right edges of the image. The location of the Hawaiian Airlines 717 is also shown. There is a single line showing the location of the palm trees for the other airport photo (by the way, you can zoom right in on these and see the trees quite clearly in Google Maps/Google Earth). 
    
    The second set of radiating lines starts at the apartment building in downtown Honolulu. The center line, towards azimuth 256.4, passes through the center of the P.R. while the other two are the limits of the daylight image section in composite2. In the closest foreground of that image you can see a US Coast Guard station with the bridge of a vessel just visible in the lower left. That may be a buoy tender and it appears the same vessel is moored there in the current images available on Google Maps. Behind it there's a "fixed" trailer with two doors and steps leading up to them which is also clearly visible in Google Maps (there's a helipad just in front of it). Behind that is the Matson container lot. The long building has changed since the last Google Map images. There are a number of large waste water treatment basins beyond that (the most prominent was under construction when the last Google Maps imagery was acquired --you can see the beginnings of its circular outline t
    here). The white "pipes" behind the basins and in front of a small building are also clearly visible in the Google Maps imagery and in the sunset portion of the composite. The vertical portion of the pipes is aligned nicely with the center of the P.R. This alignment was critical to determining the vessel's position. Finally, just offshore you can see a buoy. This is visible on the standard charts. It marks the east side of the "Kalihi Channel". I've marked its approximate location on the image.
    
    The last line indicates the approximate azimuth of the Sun in the sunset side of the composite. Since the dip of the horizon from a 300 foot tall building is just about 16 minutes of arc, the Sun would have been sitting right on the horizon at that moment as seen from sea level. It appears that the sunset photo was taken on February 7 (local date).
    
    I'm also attaching a marked-up portion of the nautical chart for this area (chart 19364, 1996). Notice the large number of navigational aids marking the Kalihi Channel which would presumably have been plainly visible dead ahead from the bridge of the Port Royal on the night they ran her up on the reef.
    
    -FER
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