[Acoustics] Through the Hull Mount

[Victor A Levesque]

Hello Brian,

I would not recommend mounting the ADCP recessed from the hull. The 
highest part of the transducers need to be at least flush with the hull. 
There is also the chance for bubble entrainment from the hull moving 
through the water. There is also a good chance of flow disturbance from 
the hull extending a considerable distance down into the water column. I 
would recommend two mounting locations; one from the bow for calm water 
conditions, and a second mount approximately mid-ships for rougher/choppy 
conditions. The ADCPs will have to be mounted so that no beams have a 
chance to strike the hull, which means the side mount could extend down 
past the bottom of the boat. The front mount may allow the ADCP to be 
shallower, but depends on the exact location and the hull shape. I have 
two mounting locations on a 21 foot ocean-going catamaran that have served 
me well.

Keep us all informed, as I once thought I wanted to through-hull mount our 
ADCP.


Victor Levesque

U.S. Geological Survey
Center for Coastal and Watershed Studies
10500 University Center Drive, Suite 215
Tampa, FL 33612-6490
813-975-8620 extension 167
FAX: 813-975-0839



"Magee,Brian [Burlington]" <Brian.Magee at ec.gc.ca> 
Sent by: acoustics-bounces at simon.er.usgs.gov
02/07/2006 11:50 AM

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Subject
[Acoustics] Through the Hull Mount






Before a hole is cut in the hull of a new 25' aluminium survey vessel to 
accommodate a Rio Grande ADCP, I would appreciate any feed back on 
operational problems that may be encountered while collecting discharge 
data. The plan is to be able to insert the ADCP down a shaft through the 
cabin floor to a point where the head is about 1" recessed from the hull. 
The top of the shaft will be water tight at the cabin floor. We understand 
the importance of a vibration free mount, beam clearance and beam 
orientation. We are concerned about possible turbulence at the transducer 
head when encountering high combined water and boat speeds. 
Any suggestions or experiences you can provide will be greatly 
appreciated. 
Brian Magee 
Environment Canada 
Water Survey Division 
Burlington ON CAN 
brian.magee at ec.gc.ca _______________________________________________
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