AR10 Knobles-Wilson "Seabed Acoustics"

Ship

Cruise Party

Departure: Mar 2, 2017

Arrival: Apr 10, 2017

Operations Area

Science Objectives

The overall scientific objective is to preform and conduct acoustic measurements in a 330 square km area known as the “mudpatch” about 60 miles south of Martha’s Vineyard in about 75 meters of water.  A nominal position in the mudpatch is about 40.47731 N   70.603934 W (see Figure 1).   The measurements and analysis of the acoustic data are planned such that they will reveal information about the properties of the upper 100 meters of the seabed.   David Knobles of KSA,LLC and Preston Wilson of University of Texas at Austin are co-chief scientists 

Science Activities

Cruise 1 of the Armstrong will occur at WHOI. Mobilization is March 01 2016.  It will proceed to the area of operations on March 02.   Its mission is to deploy (1) oceanography mooring equipment with Glen Gawarkiewicz WHOI as the PI, (2) a 1 km bottom moored horizontal line array (HLA) with Dag Tollefson of FFI Norway as the the PI, and (3) an L-array that has a vertical component of about 60 meters and a 280 meter horizontal component on the seafloor with Preston Wilson of ARL:UT as the PI.  An A-frame and supporting cranes are necessary for deployment.  ARL:UT and FFI Norway will have their winches to deploy the hydrophone cables , bottom moored measurement systems, supporting cables, floats, etc.   Likely ARL:UT will have a 20x20 foot container for command and control, and support engineering. 

Once the oceanography measurements the Neil Armstrong will transit back to WHOI to demob the Cruise 1 and Mobilize for Cruise 2 starting March 12.  There is some uncertainty as there is a plan to have NUWC personal with their small explosive devices loaded onto the ship, which would occur at NUWC.   The mission of CRUISE 2 is to deploy broadband sources, such as the NUWC devices and a Combustive Sound Source operated by ARL:UT with Preston Wilson as PI.  Andrew McNeese of ARL:UT will be the lead engineer of the deployment with assistance from David Knobles KSA, LLC as needed.  About 350-450 events are planned to be deployed throughout the Area of Operations.  On March 21 the Neil Armstrong will go back to WHOI to demob and mob for Cruise 3.

 The mission of Cruise 3 is to deploy and operate the ARL:Penn State Five Octave Research Array(FORA) array with Charles Holland and Chad Smith from ARL:PS as PIs.   The FORA array is towed from the Armstrong with a high frequency source that will record sound signals after they have reflected from the seabed.

Cruise 4 will occur after Cruise 3 and its mission is to recover all the equipment (moored sources and arrays). 

Additional Info

Stations:

Supporting documentation:

Shipboard Equipment

Shipboard Communication

CTD/Water Sampling

Critical CTD Sensors

CTD-Related Equipment

Hydrographic Analysis Equipment

MET Sensors

Navigation

Navigation

Winches

Notes on discussion about winches.  

Three groups of the joint experiment, including ARL-UT, the Norwegian Defense Research Establishment (Forsvarets forskningsinstitutt – FFI) and WHOI, led by Chief Scientists David Knobles and Preston Wilson  have suggested that we can all utilize the TSE SD-70 winch  in the Seabed Characterization Experiment from 03/01/2017 to 04/15/2017.  So, we definitely want to reserve one during the time.  FFI is also bringing a Capstan. 

 the FFI Capstan is still a 1200 lb equipment (4.3’x 7’) that on our ship is welded onto deck for use.   Our suggestion is that this work is done in port and that it is left in place once mounted.  We will require additional deck space for array cable storage and layout - Preston and David have more details on the Capstan and our other requirements.  

ARL:PS plan to use the NA winch underneath the main deck 

Standard Oceanographic Cables

Checklist

Checklist