Trailing suction hopper dredger configuration (with bubbler or pressure sensors)
This document is a step-by-step tutorial on how to configure the Hydromagic Dredging software to monitor the dredge head of a trailing suction hopper dredger. In this example we assume bubbler sensors have been mounted to the suction tube and to the hull of the vessel. Hydromagic will also support hopper dredgers equipped with inclinometer sensors. When encountering any problems by following this document, please contact our support department for assistance.
An example of bubbler sensors installed on the vessel's hull and suction tube (* marks sensor location).
Loading plugins
First of all, you have to load the plugins which are going to be used to get data like vessel position, heading, suction tube angle and draft into the software. Which plugins to load depends entirely on the dredger type and the brand or type of sensors used. In any case you have to load a plugin to retrieve position data from your GNSS receiver. This is usually one of the generic NMEA0183 plugins.
When a plugin is providing data, there should be
a green check in front of the plugin's name.
Using the bubbler sensor simulator
It is possible to test this configuration without having the sensors installed (already). Hydromagic Dredging ships with a plugin which can simulate bubbler or pressure sensors, the "Hydromagic Bubbler Simulator". Using this simulator you can manually set the depth for each of the sensors in the configuration. When everything is working correctly, you can unload the simulator(s) and load plugins for the actual hardware.
Select the "Hydromagic Bubbler Simulator Plugin" from the plugins list.
To load this simulator, select the "Preferences..." option form the "Tools" menu and select the "Devices" tab. The devices page shows the plugins which are currently loaded, and allows you to add new plugins. To do so, click the "Add..." button, and select the "Hydromagic Bubbler Simulator Plugin" from the list of available plugins and click "OK". For this example we set the depth of the draft sensor (sensor mounted to the hull of the vessel) to 2.50 meter and the sensor on the suction tube to 7.50 meter. When you use the same settings as in this tutorial, the angle of the tube should be about forty-four degrees with a dredging depth of approx nine meters.
Use the bubbler simulator to
manually set the sensor depths.
Configuring the vessel
For this type of dredger we only need to configure the primary vessel. First we have to disable the secondary vessel by de-selecting it's data sources (if not already done). To do so, select "Preferences..." from the options menu and click the "Dredging" tab. Now click the "Secondary Vessel..." button, and remove the checks for all of the plugins listed.
De-select all data sources for the secondary vessel.
For the hopper, the primary vessel will be used. Go back to the dredging tab of the preferences window and click the "Primary Vessel..." button. Make sure that all plugins which are required are loaded at this point. In the data source section, check the boxes in front of all the plugins which provide position information for the vessel. In most cases, this means all the plugins providing vessel position, vessel heading and the vessel's dynamic draft (pressure sensor). Sensors attached to the suction tube do not have to be selected here, however, since the bubbler simulator also provides a draft measurement for the vessel, we have to select the "Hydromagic Bubbler Simulator Plugin" here anyway.
Select all data sources used to position the primary vessel.
To display the hopper dredge in the map and digging views, the shape file for the vessel needs to be set. You can create or alter vessel shapes in the Vessel Designer. This tool can also be used to scale one of the shapes shipped with the software (located in "C:\ProgramData\Hydromagic\Vessel") to the dimensions of your own vessel. It is important to use accurate dimensions for all shapes used in the dredging software (vessel and dredge equipment shapes).
To select a shape for the vessel, click the "Browse..."
button to locate a vessel XML file.
When the vessel is equipped with a sensor to measure draft (i.e. either a bubbler or pressure sensor), make sure that the Y position of the sensor in the drawing is at zero (on the X-axis). When the sensor is on the zero Y position, it should be at water line level when you set the draft sensor depth to 0.000 meter in the simulator. In the example below, the location of the bubbler sensor on the hull has been marked with a '*' (asterisk):
Make sure the bubbler sensor in the drawing is at y-position zero.
With draft set to zero, hull bubbler sensor should be at water surface level.
For information on the other vessel settings in this dialog (like heading sensors, distance rings and course line options), please refer to the "Configuring Vessels" manual page.
Configuring the dredging equipment
We will now configure the dredging equipment by defining the shapes, dimensions and sensors for the different parts that make up the suction tube. When the hopper dredger has been equipped with two suction tubes, we will have to perform this step for both tubes.
Go back to the "Dredging" tab in the preferences screen, and remove any dredger configurations which are already defined here. When the list is empty, click the "New..." button to create a new configuration.
To create a new configuration, click the "New..." button.
Configuring global dredger options
Set the dredger type to "Hopper Dredger" and select the "Primary Vessel" as vessel.
Configuring dredger segments
In Hydromagic Dredging, dredging equipment is configured by combining so called "Segments" to form a complete dredging system. General information on how this works, and which type of "segments" are supported can be found in the "Configuring Dredger Segments" manual entry. A hopper dredger is configured by combining a "Trunnion", "Ladder" and "Dredge Head" segment as we will explain in the following paragraphs. For each segment you add, you have to select the type ( "Trunnion", "Ladder" or "Dredge Head" ), and an optional "friendly name".
Trunnion Offset
On a trailing suction hopper dredger, the suction tube is connected to the vessel via a so called "Trunnion". This trunnion can be above the water line, like in this example, or a "Sliding Trunnion" could be used, which means the suction tube will slide downwards through the "Sliding Trunnion". In the latter case the trunnion is located under the water surface. From the trunnion, the suction tube makes a ninety degrees angle causing an extra horizontal offset. To calculate this offset, we start with adding a "Trunnion Segment".
Add a "Trunnion" segment to specify a horizontal offset
between trunnion and dredge head.
When configuring a "Trunnion Segment", only the exact distance from the hull till the center of the dredge head is entered in the "Segment Length" field. A shape or data source can not be entered here.
The trunnion offset equals the distance between
dredge head center and the hull of the vessel.
Suction Tube
This is the most important segment of the dredging system. You can select it by changing the "Type" selection box to "Ladder (Bubble Sensor)". Make sure your shapes have the correct dimensions and the "Segment Length" is measured as accurate as possible. You have to measure the tube length from the trunnion center to the end of the dredge head. When drawing a shape of the suction tube in the "Vessel Designer", make sure the shape originates at coordinates (0,0):
Dredger shapes should originate from the (0,0) coordinate in the Vessel Designer.
Depending on which views are required, you can draw the vessel and dredge segments for the various views. The "TOP" view will be used in the map display and is mandatory! For the top view, you draw the suction tube parallel to the Y-axis starting at (0,0) and facing upwards. For the side view you start at (0.0) and the shape will be parallel to the X-axis as shown in the examples below:
 |  |
| Example of TOP view shapes for a suction tube | Example of RIGHT view shapes for a suction tube |
You also have to select which sensor is providing position information for this segment. For a suction tube, this should be an inclinometer sensor or pressure (bubbler) sensor. Make sure all plugins have been loaded as explained in the first paragraph, and click the "Add..." button to select the device. When a plugin interfaces with more then one sensor, you can select the sensor from the second drop-down box. In most cases, only one data source will be used (except when using two bubbler sensors on the suction tube). In this example we will configure one bubbler sensor which is going to be simulated by the "Hydromagic Bubbler Simulator".
Click the "Add..." button to select the plugin and sensor.
IMPORTANT: The most important setting is the "Segment Length". as soon as this is measured correctly (or look up the dimensions using a CAD drawing), your dredging depth will be correct. Incorrect dimensions in the shapes only result in a top or side view drawing which is less accurate, but it will affect your depth reading !
Add a "Ladder" segment to define the shape and length of the suction tube itself.
Bubbler Settings
When using one or two bubbler sensors on the suction tube, we have to set the location of the sensor to calculate the angle of the tube. This angle is calculated by forming a triangle with the bubbler depth as one side and the distance between the sensor and the trunnion for the other side. The image below illustrates this principle:
The angle of the tube is calculated by trigonometry. In this example the resulting angle is 44 degrees.
To enter the positions of the sensors on the suction tube, click the "Settings..." button in the "Configure Dredge Segment" dialog for the "Ladder" section (see previous paragraph). In this dialog you can choose between two configuration, a one-sensor configuration or a two sensor configuration. When you have installed a draft sensor on the hull and a single sensor on the tube, select the first option. When you have installed two sensors on the suction tube, and you are using RTK to calculate draft, use the second option.
In the distance edit boxes, you have to enter the absolute distance between the sensor and the center of the trunnion. Please measure this distance as accurately as possible! In our example (see drawing above), the bubbler is placed at 12.50 meter from the trunnion, and only one bubbler has been installed on the tube:
Enter sensor positions (offsets) in the 'Bubbler Sensor Configuration' dialog.
Dredge Head
The dredge head segment is used only to configure the dimensions of the dredge head. Only when the dredge head moves independent from the suction tube, it should be configured with its own shape and data source (plugin). When we finished adding the trunnion and one or more suction tubes, we add the "Dredge Head" segment. Just click the "Add..." button from the "Dredge Equipment Configuration" dialog, and set the "Type" setting to "Dredge Head". You will notice a "Settings..." button will become visible. Click this button and add the dredge head width and height.
Dredge head dimensions are used to calculate
which matrix cells need to be updated.
The dredge head dimensions are used to calculate the footprint size of the dredge head, so the matrix can be updated accordingly.
Add a "Dredge Head" segment to define the dimensions of the dredge head.