Re:We Need to Map the Ocean Floor
by pp19dd on Friday November 08, 2019 @10:32AM
(#21483081)
Here are "high frequency" sonar images of the Japanese WWII aircraft carrier Akagi, sunk in the Battle of Midway. They were supposedly taken by an AUV.
Best guess they used the Remus 6000 to find the ship. It looks like a torpedo.
- 3.8 meters long
- 9 km/h speed
- 22 hour 'charge'
- 6000 meter max. diving depth
- EdgeTech 2205 sidescan array (best guess)
The WWII ship is about 250 meters long, so the broad image captures about ... 1.5-2 km? Anyhow, take all that and apply it to roughly 360 million square kilometers (161 for the Pacific). Ignoring an average current here and marine traffic and conditions, just going by ideal specs, that's an imaging speed of about 13 - 18 square km per hour. It would take something like two - three thousand years to cover the oceans.
Logistical support alone for this AUV is incredible: crew of 20, four two thousand horsepower diesel engines eating 54 gallons of diesel per hour each at low throttle. Like 216 - 283 gallons of diesel per hour on average, and not counting electric generators on that vessel. The engines have to be overhauled every 4,000 hours. In other words, this effort would be a massive undertaking under current conditions, and there's not enough diesel on the planet to make it happen.
Low-resolution sonar: https://www.gannett-cdn.com/presto/2019/10/21/USAT/ecaf19d4-...
Enhanced with a manual pass: https://www.gannett-cdn.com/presto/2019/10/21/USAT/0a89e2ce-...
Best guess they used the Remus 6000 to find the ship. It looks like a torpedo.
The WWII ship is about 250 meters long, so the broad image captures about ... 1.5-2 km? Anyhow, take all that and apply it to roughly 360 million square kilometers (161 for the Pacific). Ignoring an average current here and marine traffic and conditions, just going by ideal specs, that's an imaging speed of about 13 - 18 square km per hour. It would take something like two - three thousand years to cover the oceans.Logistical support alone for this AUV is incredible: crew of 20, four two thousand horsepower diesel engines eating 54 gallons of diesel per hour each at low throttle. Like 216 - 283 gallons of diesel per hour on average, and not counting electric generators on that vessel. The engines have to be overhauled every 4,000 hours. In other words, this effort would be a massive undertaking under current conditions, and there's not enough diesel on the planet to make it happen.