TIGHAR

Amelia Earhart Search Forum => The Islands: Expeditions, Facts, Castaway, Finds and Environs => Topic started by: Ingo Prangenberg on May 30, 2012, 10:00:17 AM

Title: Side-Scan Sonar on AUV and Underwater Avalanches
Post by: Ingo Prangenberg on May 30, 2012, 10:00:17 AM
Does the Side-Scan Sonar have any penetrating capabilities or does it only skim the surface making a topographical map?

Due to the steep angle of the Drop-Off Zone, avalanches or slides of coral debree are bound to happen over time, due to natural erosion patterns, possibly covering two Pratt & Whitney “Wasp” engines at the bottom of the shelf.

I looked at the descriptions of the AUV and ROV, but didn't see anything indicating penetrating capabilities. Would be a shame to be so close and just miss it.

Title: Re: Side-Scan Sonar on AUV and Underwater Avalanches
Post by: Tom Swearengen on May 30, 2012, 10:11:18 AM
Ingo, I would think that Ric & Co, have that thought covered. I'm sure alot of planning has gone into this expedition, especially with the assets onboard the KOK, and the consultants helping out.
We can find out more Friday.
Title: Re: Side-Scan Sonar on AUV and Underwater Avalanches
Post by: Jeff Victor Hayden on May 30, 2012, 01:00:31 PM
Ingo, this site has a side scan sonar image plus images of the actual aircraf wreckage. It's a Chance Vaught Corsair. They mention that the wreckage was not subject to damage from wave action, looks pretty damaged ??? Notice the cylinder pistons but no cylinders, the nuts and bolts that hold engines together rust away and the engine literally falls apart.
http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html (http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html)
Title: Re: Side-Scan Sonar on AUV and Underwater Avalanches
Post by: Tom Swearengen on May 30, 2012, 01:20:31 PM
maybe the water is clearer, like in Hawaii where a Corsair is at 115 feet.
Title: Re: Side-Scan Sonar on AUV and Underwater Avalanches
Post by: Ingo Prangenberg on May 30, 2012, 03:44:45 PM
Very interesting footage and an eye-opener in regards to what could be found and what the possible remains of an aircraft may look like.

The application of Side-Scan Sonar in this instance had the fortune element of being on relative flat sea bottom. An anomaly would stick out like a sore thumb.

In the case that TIGHAR is investigating, I'm worried that the remains of an engine may be overlooked, because coral rubble may have cascaded on top and over it, give little or no topographical indication of what lies underneath.

Although, who is to say any wreckage (or all), has reached the bottom of the Drop-Off Zone? As previous ROV images show, this area is rather craggy and not smooth.
Title: Re: Side-Scan Sonar on AUV and Underwater Avalanches
Post by: Jeff Victor Hayden on May 30, 2012, 04:43:34 PM
Yes Ingo, the Niku reef wreck isn't one of the tourist wrecks you see on the internet, a very different place to the seabed indeed. Seamounts have quite steep reef faces which doesn't help and, as you mentioned it's a very long way down to the bottom. The spurs and grooves would tend to funnel wreckage but also, debris from the reef, sediment, coral etc... would all get piled up in the grooves and spurs.
Title: Re: Side-Scan Sonar on AUV and Underwater Avalanches
Post by: Tom Swearengen on May 30, 2012, 05:55:25 PM
WE'll know more in July