Sentinel V SC and RT Operation Manual
September
2017
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Page 87
Figure 43.
Load Cage
Photo courtesy of Angela Cates, UNM.
Using an Over-the-Side Mount
The over-the-side mount is common when the ability to move the Sentinel V ADCP from one platform to
another is needed. The mount must be as rigid as possible to limit the amount of pitch and roll applied to
the ADCP. Although the tilt sensor can measure a ±90° influence, anything beyond 15° will cause bias to
the data that cannot be removed. No matter what mounting type used, the ADCP must be below the bub-
ble layer. Bubbles will cling to the urethane faces of the ADCP and reduce the range to almost nothing.
Usually a mount somewhere aft of amidship is used. A stern mount will cause all sorts of problems due to
propeller wake, bubbles and turbulent water conditions.
The most common over-the-side mounting method for ADCPs uses a Kentucky Mount style. For more in-
formation, see the following:
•
http://hydroacoustics.usgs.gov/movingboat/pdfs/KYMount.pdf
•
http://hydroacoustics.usgs.gov/movingboat/mbd_deployments.shtml
Our transducer assembly is sturdy, but TRDI did not design it to withstand collisions with all
floating objects. TRDI strongly suggests protecting the Sentinel V ADCP if this is a possibility.
Avoid using ferro-magnetic materials in the mounting fixtures or near the Sentinel V ADCP.
They affect the compass. Use titanium or 316 stainless steel hardware.
Over-the-Side Mounting Special Considerations
Use the following suggestions when mounting the Sentinel V ADCP to a platform.
•
It is desirable to rigidly mount the Sentinel V ADCP to the platform. Avoid the free spinning of
the ADCP in this application. The ADCP must stay in the water at all times.
•
The ADCP must be mounted deep enough so that turbulence caused by its movement through
the water does not allow air bubbles to be attached to the transducer faces.
•
Avoid mounting the ADCP near motors and thrusters. They cause air bubbles and will cause bias
to the internal compass.
•
Avoid mountings that will cause the ADCP to see severe accelerations.
