jnmeade
Cleared for Takeoff
Nauticos' search of the 80% probability area terminated recently with nothing found. The area is mostly to the north and west of Howland Island. Of course, it is based on best estimates and assumptions.
For example, an analysis of Fred Noonan's habits in navigation concluded that he most likely flew to the north of the course line on the final miles so that when he hit the line of position through Howland the error would be offset to the North and the subsequent course change would be to the right, down the line of position to Howland. If that is not what he did, the search area should be offset somewhat. No one knows what he did in fact do.
The search was conducted this time using Remus 6000, an autonomous underwater vehicle with an estimated 18-24 hour mission duration based on Li-Ion battery life (they got it up to 25 hours late in the search). The AUV swam at about 80m above the seabed which was around 5400 meters deep. The sonar range was about 600 meters. After a 45-60 minute review of data and inspection, the AUV is ready for another trip.
Sonar based graphics of objects found included a wooden mast, a coil of cable and a metal boom of some kind. They were quite sharp and distinctive.
Unlike last time when the ship towed a sonar, this time the ship released AUV and waited for it to emerge about a day later.
The ship determined a position or waypoint by dropping a $50,000 transponder which took 2 hours to descend to the floor. The ship would then steam around it taking bearings on each 120° leg, locating it's position within 5m. The ship then moved to another location and dropped another transponder. This established a very accurate reference line for the AUV to follow. The transponder are tied to a releasable 150 pound weight and are buoyed by 2 glass balls. On command the weight is released and the balls float the device to the surface for reuse. Because of the pressure, the inside of the glass balls scales off and after enough trips down the glass has scaled off enough that it can't stand the pressure and implodes. There is $100,000 worth of transponders on the bottom of the Pacific off Howland Island.
Don't ask me, I don't know. 
I don't know how many times they had to drop transponders to set up a line or if each line could be used for a number of searches or swathes.
What's next? The briefing I heard didn't say. It was given by the 3 Rockwell Collins Radio Club members who were part of the search team.
This account is based on my notes and understanding so take it with a grain of salt.
Scroll down this URL for a few photos of the ship and crew.
http://nauticos.com/category/explorer-insights/
For example, an analysis of Fred Noonan's habits in navigation concluded that he most likely flew to the north of the course line on the final miles so that when he hit the line of position through Howland the error would be offset to the North and the subsequent course change would be to the right, down the line of position to Howland. If that is not what he did, the search area should be offset somewhat. No one knows what he did in fact do.
The search was conducted this time using Remus 6000, an autonomous underwater vehicle with an estimated 18-24 hour mission duration based on Li-Ion battery life (they got it up to 25 hours late in the search). The AUV swam at about 80m above the seabed which was around 5400 meters deep. The sonar range was about 600 meters. After a 45-60 minute review of data and inspection, the AUV is ready for another trip.
Sonar based graphics of objects found included a wooden mast, a coil of cable and a metal boom of some kind. They were quite sharp and distinctive.
Unlike last time when the ship towed a sonar, this time the ship released AUV and waited for it to emerge about a day later.
The ship determined a position or waypoint by dropping a $50,000 transponder which took 2 hours to descend to the floor. The ship would then steam around it taking bearings on each 120° leg, locating it's position within 5m. The ship then moved to another location and dropped another transponder. This established a very accurate reference line for the AUV to follow. The transponder are tied to a releasable 150 pound weight and are buoyed by 2 glass balls. On command the weight is released and the balls float the device to the surface for reuse. Because of the pressure, the inside of the glass balls scales off and after enough trips down the glass has scaled off enough that it can't stand the pressure and implodes. There is $100,000 worth of transponders on the bottom of the Pacific off Howland Island.
Don't ask me, I don't know. I don't know how many times they had to drop transponders to set up a line or if each line could be used for a number of searches or swathes.What's next? The briefing I heard didn't say. It was given by the 3 Rockwell Collins Radio Club members who were part of the search team.
This account is based on my notes and understanding so take it with a grain of salt.
Scroll down this URL for a few photos of the ship and crew.
http://nauticos.com/category/explorer-insights/
