CB-Series Data Buoy Instrument Cage Installation

The NexSens buoy instrument cage attaches to the bottom of CB-Series buoys for water sensor deployments while simultaneously lowering the center of gravity and increasing stability.

Model number CAGE is 39″ (99 cm) in length and is normally used with the CB-50, CB-150, CB-250, and CB-450 buoys. It is an optional accessory for the CB-50 and comes standard with the others.

Model number CAGE-L is 44″ (112 cm) in length and has a wider profile. It comes standard with CB-650, CB-950, and CB-1250 buoys.

Model CAGE instrument cage product page

Figure 1: Model CAGE instrument cage.

Model CAGE-L instrument cage product page

Figure 2: Model CAGE-L instrument cage.


The cage is a critical component of the ballast weight of a data buoy and provides a mounting location for additional ballast weight to be added as needed.

Attachment to the internal frame of a data buoy is simple using the provided hardware.

  1. Use the provided bolt, lock washer and castle nut to attach the cage to the buoy frame.

Figure 3: Bolt installation and cage connection.


  1. Tighten firmly with a pair of 1-1/8” wrenches such that the lock washer is flattened and the bolt hole is aligned with a notch on the castle nut.

Figure 4: Secured cage.


  1. Place the cotter pin through the bolt hole and bend the long leg of the pin.

Figure 5: Cotter pin with bent leg for security.


CB-CCA Anti-Rotation Collar

The single bolt connection is sufficient for small buoys in calm waters. However, a CB-CCA Buoy Cage Anti-Rotation Collar may be used for added security in rough waters or when suspending sensor strings from the cage. It is included standard and should always be used with buoy models CB-650 and larger that come with the CAGE-L. For installation instructions, see the CB-CCA installation guide.

NexSens CB-CCA collar product page

Figure 6: CB-CCA collar.