Trailing suction hopper dredger configuration (with inclinometer 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 an angle sensor (inclinometer sensor) has been mounted to the suction tube. Hydromagic will also support hopper dredgers equipped with pressure or bubble sensors. When encountering any problems by following this document, please contact our support department for assistance.

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.

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.

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.

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". Make sure your shapes have the correct dimensions and the "Segment Length" is measured as accurately 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 separate sensors and plugins to monitor horizontal movement as well).

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 lookup 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.

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 it's 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.