CB-250 Data Buoy Overview

The CB-250 data buoy strikes a balance between compact and easy to deploy, yet buoyant and powerful enough to be deployed in larger water bodies including lakes, rivers, coastal waters, harbors, estuaries and other freshwater or marine environments. Like all solar-powered NexSens CB-Series data buoys, it is a highly customizable platform that may be configured with NexSens or user-supplied electronics. It supports a wide variety of topside and subsurface sensors and measurement instruments.

 CB-250 data buoy product page

Figure 1: CB-250 data buoy.


Key Components and Definitions

Buoy Hull

Constructed of cross-linked polyethylene foam with a durable polymer outer layer and rugged stainless steel frame providing a net buoyancy of 250 lb (114 kg). Three 2” pass-through holes with female NPT bottom threads allow for quick connection of instrument deployment pipes and custom sensor mounts.

Data Well

The waterproof compartment located in the center of the buoy hull for placement of system electronics such as batteries and data loggers. On the CB-250 model, the data well has a 10.3” (26.2 cm) diameter and 19.5″ (49.5 cm) height.

For complete NexSens systems, the data well is fitted with a CB-A01-2 or CB-A05 battery harness and the X2-CB data logger, which has (5) waterproof UW sensor ports supporting common standards such as SDI-12, RS-232 and RS-485. Waterproof sensor connection is achieved by factory installation of sealed UW connectors on sensor cables.

For users supplying their own electronics, the CB-250 is delivered as an open platform with empty data well or with battery only. A data well top plate can be supplied in many configurations, for example:

  1. A standard CB-PTL Pass Through Lid for passing of instrument cables through gland fittings
  2. A CB-PTL lid with UW8-BULK sensor bulkhead cable assemblies
  3. A CB-MCL Wet-Mate Lid for use with marine-grade bulkhead connectors
  4. A blank lid with only UW6-BULK power cable assembly and vent that users may drill their own holes and install connectors into
  5. No lid, only a drawing showing bolt hole locations for users who want to machine their own lid

Figure 2: Buoy data well and pass-through holes.

Figure 3: Data well top plate.


Solar Tower

Three 15W solar panels capture sunlight from any direction and charge batteries located inside the data well. The tower also supports the mounting of an M550 solar marine light for nighttime visibility. Aside from regular cleaning to ensure solar panels are unobstructed from receiving maximum sunlight, there is little to no maintenance required. However, solar assemblies may be function tested if any performance issue is suspected by placing in the sun and measuring output on the UW-6 (6-pin) port plug.

Figure 4: CB-250 solar tower.


Buoy Frame

The skeleton of the buoy is comprised of 316 stainless steel with topside lifting eyes and subsurface mooring eyes for single and multi-point moorings. The frame supports attachment of an instrument cage for secure connection of subsurface sensors and additional ballast weight for stability.

Figure 5: CB-250 buoy frame with instrument cage installed.


Key Specifications

The key specifications of the CB-250 buoy are given below:

  • Hull Outer Diameter: 30.0” (76.2cm)
  • Hull Height: 20.0” (50.8cm)
  • Data Well Inner Diameter: 10.3” (26.2cm)
  • Data Well Height: 19.5″ (49.5cm)
  • Pass-Through Hole Diameter: 2.0″ (5.1cm)
  • Tower Height: 20.0” (50.80cm)
  • Solar Panels: 3x 15-watts
  • Weight: 115 lb (52kg)
  • Net Buoyancy: 250 lb (114kg)
  • Hull Material: Cross-linked polyethylene foam with polyurea coating & stainless steel deck
  • Hardware Material: 316 stainless steel
  • Mooring Attachments: 3x 3/4” eyenuts