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NexSens Technology CB-75 User Manual

Data buoy
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CB-75 Data Buoy
User Guide
Last Revision: 27 December 2024
Date Generated: 10 January 2025
Copyright © 2025 NexSens Technology, Inc.

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Summary of Contents for NexSens Technology CB-75

  • Page 1 CB-75 Data Buoy User Guide Last Revision: 27 December 2024 Date Generated: 10 January 2025 Copyright © 2025 NexSens Technology, Inc.

  • Page 2: Table Of Contents

    Buoy sizing and power budget Buoy ballast Buoy mooring Electrical connections Safe deployment 2. Buoy Assembly Instrument Installation in CB-25 or CB-75 Data Buoy Cage Installation Sensor Cable Routing M550 Beacon for CB-Series Data Buoys Installation Operation Use of Sacrificial Anodes on CB-Series Data Buoys...
  • Page 3 Deployment 4. Warranty 5. Service Request Service Request...

  • Page 4: General

    1. General CB-75 Data Buoy Overview The CB-75 Data Buoy is a simple, compact platform that integrates the X3-SUB Submersible Data Logger for both water and atmospheric observations. The buoy features (3) 1.5″ sensor pass-through ports, an integrated solar tower with (3) 4-watt solar panels, and a topside plate supporting a solar marine light, weather stations, and other environmental sensors.
  • Page 5 Solar Panels: 3x 4-watts Weight: 28 lb. (12.70kg); 40 lb. (18.20kg) with X3-SUB Net Buoyancy: 75 lb. (34.00kg) Hull Material: Cross-linked polyethylene foam with polyurea coating & stainless steel deck Hardware Material: 316 stainless steel Mooring Attachments: 3x 3/8” eye nuts...

  • Page 6: Cb-Series Data Buoy Planning & Precautions

    CB-Series Data Buoy Planning & Precautions Buoy deployments are usually complex operations that involve many elements including sensors, data loggers, mounting hardware, and mooring equipment. Careful planning and precautions are essential to the success of a buoy project, not only for system operation and data collection but also to ensure the safety of project personnel and minimize the risk of damage to expensive system components.

  • Page 7: Safe Deployment

    CB-Series data buoys contain a waterproof data well constructed of stainless steel where batteries are mounted. Whenever installing or maintaining battery systems, use caution to avoid short-circuiting of battery poles to the metal walls of the data well. Gloves and tools with rubber grips are recommended, and any exposed connections should always be covered with electrical tape or other suitable coverings.

  • Page 8: Buoy Assembly

    2. Buoy Assembly Instrument Installation in CB-25 or CB-75 Data Buoy The CB-25 and CB-750 Data Buoy have a solar tower plate allowing the installation of top- side mounts for GPS units and weather stations. Three 1.5″ sensor pass-through ports and the optional purchase of an EXO cage for the EXO series of YSI EXO sondes allow for multiple platforms for deploying subsurface water quality sensors.
  • Page 9 2. Use a Philips head screwdriver to remove the internal screws on the solar tower. Solar tower removal. 3. Use a Philips head screwdriver to remove the outside screws holding down the X2- SDLMC. X2-SDLMC removal.
  • Page 10 4. Use the provided bolt, lock washer and castle nut to attach the cage to the buoy frame. a. Insert the bolt through the center hole within the buoy hull. b. Place the black ballast washer between the cage and the bottom buoy plate. Bolt installation and cage connection.

  • Page 11: Sensor Cable Routing

    Sensor Cable Routing 1. Route the sensor cables underneath the solar panel opposite the sensor ports. a. Ensure to insert enough cable within the solar tower to avoid tension on the connector. b. The connector should remain in a nearly vertical angle while connected. c.

  • Page 12: M550 Beacon For Cb-Series Data Buoys

    M550 Beacon for CB-Series Data Buoys NexSens M550 Solar Marine Light is a common accessory added to NexSens data buoys up to and including the CB-450. Depending on the configuration, it has a 1-3 nautical mile range and is normally delivered with flange mount hardware, yellow color, and default 15 flash/minute pattern (Model: M550-F-Y).

  • Page 13: Operation

    Figure 2: M550 beacon mounted on top of the Figure 3: Pole-mounted beacon on the XB-200 CB-450 data buoy. data buoy. Operation The M550 is controlled using an IR programmer that is normally provided with the beacon. Figure 4: IR remote...
  • Page 14 The IR programmer can be used to perform the following functions: Turn beacon on and off Check the battery pack charge status Change the flash pattern Change the flash intensity...

  • Page 15: Use Of Sacrificial Anodes On Cb-Series Data Buoys

    Use of Sacrificial Anodes on CB-Series Data Buoys Sacrificial zinc anodes are recommended for use on CB-Series data buoys any time they will be used in saltwater environments. This helps to prevent corrosion on the stainless steel frame, as zinc is a more active metal that will be consumed while protecting the stainless steel.
  • Page 16 frequent inspection and replacement of anodes as needed can extend the life of a data buoy significantly in saltwater. Sacrificial anodes are normally not necessary for buoys used in freshwater except in special circumstances. It is therefore generally recommended only to order anodes with buoys intended for use in brackish or saltwater.

  • Page 17: Deployment

    3. Deployment CB-Series Data Buoy Ballast Weight & Stability Ballast weight may be needed to prevent overturning a CB-series buoy system and ensure stability in the water. The center of gravity of NexSens CB-Series buoys is near the water surface without instruments connected. Therefore, any top-side weight added above the water’s surface (e.g., sensors, sensor mounts) must be appropriately counterbalanced by ballast weight below the surface (e.g., instrument cage, chain, anchors, etc.).

  • Page 18: Top-Side Weight

    Top-Side Weight Top-side weight is any weight mounted on the buoy above the water surface or the buoy’s center of gravity. Weight located further from the buoy’s center of gravity will cause greater instability of the buoy. For example, suppose a weather sensor is mounted 36″ above the water surface (Figure 2).

  • Page 19: Ballast Weight

    Ballast Weight Ballast weight is any weight mounted on the buoy below the water surface or the buoy’s center of gravity. Contrary to top-side weight, a ballast weight added further below the surface (Figure 4) will provide a more significant stabilizing effect than the same size weight mounted closer to the surface (Figure 5).

  • Page 20: Mooring Nexsens Data Buoy Platforms

    Additionally, the weight associated with biofouling growth can impact the buoy buoyancy and mooring performance. Minimum recommended ballast weights for NexSens Technology data buoys can be reviewed at the link below. NexSens Technology Buoy Ballast Weights More information on buoy ballast can also be found at the link below.
  • Page 21 1. Catenary Moorings For shallow deployments with minimal wind, wave and current loading, most data buoys utilize catenary moorings. Shallow deployments can be designed with all chain or a combination of heavy bottom chain and light water column chain. Deeper water moorings may need to use a combination of chain and rope.
  • Page 22 Small-buoy catenary moorings Additional surface or subsurface floatation may be required for smaller buoyancy buoy applications where the floatation may not be adequate to support the mooring weight. Extra floatation can also free motion for wave measurement applications or offer additional resistance to horizontal loading.
  • Page 23 Horizontal Loading As wind, wave and current loads increase, the buoy is driven away from the anchor and mooring can be pulled taut resulting in the buoy listing to one side. Damage can result with topside equipment and solar panels becoming submerged. Additional surface or subsurface floatation may be required.
  • Page 24 2. Semi-taut two point moorings For calm, shallow water with limited horizontal loading, semi-taut two point moorings can be utilized. These moorings are useful for suspending sensor lines by pulling the mooring lines free and clear. Rough water, shifting bottom or horizontal loads can tangle two point moorings and lead to chafing and cable failure.
  • Page 25 3. Inverse-catenary (S-shape) moorings Inverse-catenary moorings are often referred to as S-shaped moorings. Floats and weights on the mooring lines create an S-shape, which provides spring action in the water column. Waves and water level changes are easily managed. This mooring type is most common on deep water deployments but has utility in shallow rough water applications.

  • Page 26: Cb-Series Data Buoy Deployment Tips

    CB-Series Data Buoy Deployment Tips NexSens Technology supplies mooring hardware to support user-designed systems but does not endorse any particular mooring strategy for any specific application and does not take responsibility for mooring performance or damage resulting from mooring failure.

  • Page 27: Buoy Deployments

    Note: Shackle sizes are dependent on the thickness of the bottom chain. Shackles shown in the images below are used for 1/2″ galvanized chain, which is standard in most applications. Figure 2: Shackle connections between the Figure 3: Shackle connections between the buoy tether line and marker buoy.

  • Page 28: Single-Point Mooring Buoy Deployments

    equipment (e.g., workboat, lifting rig for heavier systems, gloves, safety footwear, etc.) is essential to deploy any buoy system safely. Buoy systems are heavy, and personnel can quickly become entangled with mooring lines and anchors. Safety and flotation gear should be worn at all times when working on or near the water. Remember to perform a complete system test onshore before buoy deployments.

  • Page 29: Two-Point And Three-Point Mooring Buoy Deployments

    Figure 7: Single-point mooring system on CB- 450 data buoy. Two-Point and Three-Point Mooring Buoy Deployments 1. Connect all mooring components inside the boat. Stage the components so that they can be lifted over the side of the boat and laid out without becoming entangled. 2.

  • Page 30: Planning A Medium-Deep Water Mooring For Small Data Buoys

    Planning a Medium-Deep Water Mooring for Small Data Buoys Note: NexSens Technology supplies mooring hardware to support user-designed systems but does not endorse any particular mooring strategy for any specific application and does not take responsibility for mooring performance or damage resulting from mooring failure.
  • Page 31 Mooring Line Length and Drift Radius In order to determine the appropriate mooring line length, it is first necessary to have a fairly accurate water depth measurement at the deployment site and overview of the expected water level changes. In most applications, mooring line lengths should be ~50% greater than the median water depth to account for water level fluctuations.
  • Page 32 Figure 2: Depiction of horizontal loading Figure 3: Force diagram representing external resulting in buoy listing to one side. forces acting on buoys in natural environments. Chains for Controlled Movement vs. Ballast Weight One strategy to provide an adequate potential mooring line length but provide some limitation on the buoy’s free movement is to use a heavy bottom chain as a part of the mooring system.
  • Page 33 Figure 4: Mooring system overview with trawl float supporting bottom chain. System Maintenance A secondary consideration in calculation of mooring line length is serviceability of the instruments deployed. For practicality, it may be desirable to be able to access sensors mounted along the mooring line without having to lift the entire anchor system from its placement.

  • Page 34: Mooring Hardware Materials

    Mooring Hardware Materials Mooring Lines A wide range of hardware options are available, and these can largely be selected based on site conditions, but there are a few critical points which should be considered. Sensors suspended below the buoy frame can optionally be mounted onto NexSens-issued stainless steel mooring lines.
  • Page 35 Figure 5: S-shaped mooring with weight applied to avoid mooring rope coming into contact with sensors. Mooring Connections To connect mooring components together, various shackle types may be used. Here, it is important to consider the materials of construction. The internal frame of CB-Series buoys is constructed of Type 316 stainless steel.
  • Page 36 suspended below the depth of the buoy’s internal frame. Deployment Due to the size and total weight of medium-deep water moorings, it is strongly recommended to deploy using an appropriately-sized vessel equipped with a crane and winch for controlled lifting and release of the mooring system and buoy. The following describes the process for a typical deployment.
  • Page 37 Figure 8: Figure 7: Anchor being Anchor lowered into supported by water with off-load hook. crane. 3. After drawing the wire of the crane back to its original parked position, begin slowly paying out the mooring line using the winch. Before the anchor touches the seafloor, there is the possibility to make fine adjustments to the mooring location by carefully navigating the vessel, being sure to avoid tangling of the mooring line with the motor.
  • Page 38 and off-load hook as with the anchor, or by placing it into the water through a bow gate if the vessel is equipped with one. Once deployed, observe the buoy’s movement to ensure it appears to be stable. If the buoy is equipped with a GPS device, track the coordinates for a few days to ensure it is staying within the desired drift radius, and consider configuring a geofence alarm to provide notice if the buoy moves outside the desired boundaries.

  • Page 39: Warranty

    Limitation of Warranty This warranty is not applicable to any NexSens Technology, Inc. product damage or failure caused by failure to install, operate or use the product in accordance with NexSens Technology, Inc.

  • Page 40: Service Request

    5. Service Request Service Request To return equipment for evaluation and repair, request Return Authorization (RA) at the following link: NexSens Return Authorization An email authorization receipt with a reference number will be sent to print and include with your shipment. Products within the warranty period will be fixed at no charge.

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