Picture of Three Acoustic Doppler Velocity Meters

Three acoustic doppler Velocity meters (ADVMs) that have different frequencies. The ADVMs are raised out of the water for servicing. 

This picture shows three acoustic doppler Velocity meters (ADVMs). The ADVMs are positioned like a triangle with one ADVM on top and the two others below and side by side. These ADVMS are on an aluminum mount which is currently out of the water and being held in place by some pliers attached to rail below the bottom left part of the mount.  The mount is attached to a rail, so the mount and attached ADVMs can be moved up and down through the water column and out of the water column to be serviced which this picture is illustrating. The aluminum rail that the ADVMs are mounted to is attached to a pier structure. There are black cables coming out from the top of the ADVMs, and the loose cables on the left side of the ADVMs. There is a boat below the ADVMs, and rope attached to a cleat and the same is wrapped around a pier structure.