Settings / Vessel Display
Vessel Display (Own-Ship & AIS)
These control how your vessel and other vessels (AIS targets) are depicted on the Navigation display. Most settings apply equally to your vessel and to AIS targets. Note that your vessel will only be depicted if its location is known from the devices integrated GPS or from GPS information supplied from external NMEA.
- Course Vectors: The speed vector controls how long of a course vector to display for all vessels. You can disable course vectors entirely or select 1, 3, 6, 12, or 60 minutes. A final option is to use a vector corresponding to 1 day. The vector will be displayed so it shows where the vessel will travel in the given amount time if it maintains current course, speed, and rate-of-turn. If a 1 day course length is selected, then the vector will be straight.
- Variable Course Predictor: (Only SEAiq Pilot) When enabled, a panel at the bottom of the navigation display can be used to adjust the length of the predicted courses, measured in minutes.
- Use Straight Course Vectors: (Only SEAiq Pilot) When enabled, course vectors for all vessels will be straight (no turning). Note that this setting only affects course vectors and not other similar item such as swept path, docking paths, etc. This is intended to be used in situations where incorporating rate-of-turn into course vectors may be confusing, such as when there is strong drift and slow vessel speed.
- Show Course from Bow & Stern: (Only SEAiq Pilot) When enabled, course vectors for all vessels will be shown from both bow and stern, instead of center or conning position. The dual vectors are only shown if sufficient information is available, such as as ROT and HDG, for the two vectors to be useful. This does not affect Trial ROT, which is only shown from center/conning.
- One Minute Ticks: Enable to display tick symbols on course vectors at positions corresponding to every minute.
- Six Minute Ticks: Enable to display tick symbols on course vectors at positions corresponding to every 6 minutes.
- Show Vessel Heading: (Only SEAiq Pilot) When enabled, heading lines are displayed.
- Show Beam Lines: (Only SEAiq Pilot) When enabled, beam lines are drawn amidships perpendicular to the vessel's heading.
- Use Fill for Vessels: When enabled, vessel (Own-Ship and AIS) use fill in addition to outlines. This can make them easier to identify. Use with care because this may obscure features beneath the vessels.
- Use True-scale When Small: (Only SEAiq Pilot) Vessels are normally only displayed in in True-scale when the scaled vessel on the display is at least 6mm long. When enabled, the threshold is reduced to 1.5mm, which means True-scale will be used at much smaller sizes.
- Use Course When Heading Unavailable: Normally, True-scale will only be used if the vessel's heading is known. When this setting is enabled, the vessel's course will be used if the heading is not known. In many cases a vessel's course may not match its heading; this will result in inaccurate display.
- Use Recreational Outline for Own-Ship: (All but SEAiq Pilot) When enabled, a different outline is used for Own-Ship.
- Show Predicted Position: (Only SEAiq Pilot) Show predicted position of Own-Ship.
- Buffer Around Own-Ship: (Only SEAiq Pilot) When enabled, a buffer is drawn around Own-Ship.
- True-scale History: (Only SEAiq Pilot) When enabled, a recent history of Own-Ship True-scale positions is displayed.
- Show Side-Heading Lines: (Only SEAiq Pilot) When enabled, additional heading lines are displayed on either side of Own-Ship's heading, extending 2NM from the center of the vessel. You can choose relative bearings of 3, 5, or 10 degrees.
- Show Swept Path: (Only SEAiq Pilot) When enabled, shows swept path of Own-Ship. The swept path is indicated by lines that begin from the current outermost extremities of the vessel to port and starboard from the current course of the vessel. This is useful primarily when the vessel is drifting due to current or wind and the effective beam may be significantly higher than the beam. The length of the swept path is same as the predicted course length, but at most 6 minutes.
When Swept Path is enabled the vertical status bar will include a panel with Own-Ship's beam width, drift (crab) angle, and effective beam width at the current time.
Finally, when n Electronic Bearing Line (EBL) is selected which is between Own-Ship beam and length, the EBL panel in the status bar will show the maximum drift possible for Own-Ship's effective beam to be at-most the length of the EBL. This is the maximum angle and assumes the vessels COG approaching the EBL is a right angle.
Please keep the following caveats in mind:
- The calculations used assume the vessel is rectangular.
- The swept path uses the beam and length information supplied by AIS or the values in the Own-Ship settings. Typically, correspond to the LOA and the molded beam. If you instead want to have the LWL and the beam (at waterline), you can adjust the Own-Ship settings.
- The effective beam width is for the current moment in time. It may change if the vessel's HDG or COG changes.
- The predicted swept path assumes ROT has a similar effect on course as heading. However, as a vessel turns in the presence of current or wind, the course and heading will normally not be affected the same.
- Trial Rate-of-Turn: (Only SEAiq Pilot) When enabled, a slider appears below the main navigation panel. You can use this to set a Trial ROT of up to 30 degrees per minute in either direction. An orange-colored course vector is then displayed (in addition to the normal black one) that shows the vessel's predicted course at that rate-of-turn. The Trial ROT is displayed above the slider along with the turning radius at the current SOG (if the vessel speed is moving at least 1kn).
Similarly, if following a route, the goal waypoint will be shown with an additional turning radius corresponding to the current SOG.
You can zero the Trial ROT by pressing the O button above the slider. You can disable it by pressing the X button.
A switch labeled CHL (Curved Heading Line) is also available. CHL controls the behavior of the course vector when approaching waypoints/turns. When CHL is enabled and Own-Ship is within 3NM of a turn, the predicted course will straighten when it reaches the bearing for the next course leg. CHL is automatically disabled when Use Drift in Course Predictions is enabled.
- Trial Speed: (Only SEAiq Pilot) When enabled, a slider appears below the main navigation panel. You can use this to set a Trial SOG of up to 25kn. The slider value is used for all calculations related to Own-Ship speed. Because of the pervasive effect of this setting, the panel for the slider has a magenta background.
Example uses include testing for effects of changing on ETA, CPA, or meeting points with other vessels.
As opposed to Trial ROT, this does not create a new predicted course vector. However, the Trial SOG will be used in both the normal predicted course vector and in the Trial ROT course vector (if enabled).
This mode is disabled by pressing the X button in the panel.
- True-scale Status: Shows current status of True-scale for Own-Ship. This is used for trouble-shooting why Own-Ship may not be displayed in true-scale. See above for the list of conditions that are required for True-scale display of a vessel. Similar information is available in "True-scale Outline" diagnostic for an AIS target.
- Show Own-Ship Wind & Drift: When enabled (and appropriate sensor data is available from NMEA), vectors are shown for apparent wind, true wind, and drift. The vectors originate from the center of Own-Ship. The apparent wind has one set of "tails"; the true wind has two sets of tails. The drift has an arrow head pointing away from Own-Ship. The vectors only indicate direction, not speed. In some cases, not all vectors may be shown.
Important: normally the sensor data required for this feature is not available from the AIS Pilot Plug that pilots use, so turning this on will have no effect.
- Use Ship Shape for Unscaled Own-Ship: (Only SEAiq Pilot) When enabled, a ship image will be used for unscaled Own-Ship. This is used instead of the concentric circles specified by IHO S-52 standard.
- Use Green Fill for Own-Ship: (Only SEAiq Pilot) When enabled, the True-scale image for Own-Ship will have green fill instead of the normal IHO S-52 black color. See Settings / Raster for other options that can affect Own-Ship coloring.
- Use Red for Targets: When enabled, AIS targets are drawn using a red color that some people find contrasts better than the standard blue color.
- Target Labels: Setings for control of labels on AIS targets.
- Flag AIS Targets by Type: When enabled, each AIS target with is shown with a flag that has color according to its type:
- Blue: Passenger vessels
- Green: Cargo ships
- Red: Tankers
- Yellow: High-speed vessels
- Medium Blue: Tugs, Pilot boats, etc
- Magenta: Yachts, Other
- Brown: Fishing boats
- Hide Course Vectors for Tugs: (Only SEAiq Pilot) When enabled, course vectors for AIS targets marked as tugs are not displayed. This can be helpful when tugboats are surrounding Own-Ship and their course vectors clutter the display.
- Show AIS CPA: When you select an AIS target, an information box appears with information about the Closest Point of Approach (CPA) with Own-Ship. This information is also displayed on the vertical status bar. You can also enable Show AIS CPA in order to have the CPA positions displayed visually. The positions of the AIS target and Own-Ship when they are at the estimated CPA are marked with magenta circles. Dotted magenta lines will show the path of vessels to the CPA and connect the positions. This can be helpful to understand the relative positions of the vessels when they are at the CPA.
CPA gives distances based on center of Own-Ship and target. This assumes vessels maintain course (COG & SOG), regardless of current ROT.
- Show AIS BCR: (Only SEAiq Pilot) When you select an AIS target, an information box appears with information about the Bow Crossing Range (BCR) with Own-Ship. This information is also displayed on the vertical status bar. You can also enable Show AIS BCR in order to have the BCR positions displayed visually. The positions of the AIS target and Own-Ship at the estimated point are marked with orange circles. Dotted orange lines will show the path of vessels to the BCR and connect the positions. This can be helpful to understand the relative positions of the vessels.
BCR gives distances for centers of Own-Ship and target, not their bow or stern. The calculation assumes vessels maintain (COG & SOG), regardless of the current ROT.
- Hide AIS Aids-to-Navigation: (Only SEAiq Pilot) When enabled, AIS Aid-to-Navigation (ATON) are not displayed. This does not affect chart symbols, only symbols resulting from AIS. Some mariners find AIS ATON to not be very useful.
- Hide Recreational Vessels: (Only SEAiq Pilot) When enabled, AIS targets identified as recreational vessels are not displayed. This capability relies on the vessel type information reported by AIS. Recreational vessels include the following types (again, as identified by AIS): Diving, Sailing, and Pleasure vessels.
Recreational vessels at least Settings / Meeting Points / Small Vessel Length will be displayed, regardless of this setting.
- Hide Fishing Vessels: (Only SEAiq Pilot) When enabled, AIS targets identified as fishing vessels are not displayed. This capability relies on the vessel type information reported by AIS.
Fishing vessels at least Settings / Meeting Points / Small Vessel Length will be displayed, regardless of this settings.
True-scale Vessel Display
When zoomed in sufficiently far, SEAiq will display vessels (both Own-Ship and AIS targets) scaled and positioned to their approximate shape. This can be useful in many situations, such as when navigating in small areas.
In order for True-scale display to be used for a given vessel, the following conditions must all be met.
- The current position of the vessel must be known.
- The vessel's heading (HDG) must be known. Alternatively, if the setting Use course if heading is not available is ON, the vessel's course over ground (COG) will be used when HDG is not available. IMPORTANT: course may not match the heading and this may result in an incorrect representation.
- The size of the vessel must be known. This size information includes the relative location on the vessel of the GPS antenna.
- The display must be zoomed in sufficiently far for the displayed vessel to be at least 8mm in size. This threshold is 2.0mm when Show True-scale when small is ON,
The size of Own-Ship may come from the local AIS feed (in "AIVDO" sentences) or may be set manually by the user. The settings in the AIS feed are given preferrence, unless Override AIS for Own-Ship Size is set to ON (in which case the manual settings will always be used).
For AIS targets, the size information is reported less frequently than the vessel's position so there may be a delay after a vessel is first displayed before the shape is available. SEAiq saves this information to prevent the delay when the same vessel is encountered again.
Frequently Asked Questions
- Why is my vessel not being displayed in True-scale? See the condition listed above that need to be met for True-scale display of a vessel. See the Status field under the Own-Ship settings for the current status of True-scale for your vessel. This will explain why or why not True-scale is being used.
- Why is an AIS target not being displayed in True-scale? See above and the "True-scale Outline" diagnostic field for the AIS target.
- Why are some vessels displayed in True-scale and some not? It may be the case that some vessels meet the conditions required for True-scale display and some do not. For instance, a large vessel may large enough to meet the 6mm size requirement at the current zoom, while a small vessel does not.
- Why is a vessel being shown in the incorrect position? SEAiq requires accurate information to display vessels correctly. It is unfortunately common for AIS information, especially the size and location of GPS antenna, to be incorrectly configured in the AIS transponder. You can see the information that is being reported by looking in the Diagnostics information for an AIS target. Another source of error can occur if the Use course if heading is not available is ON: if course is used due to lack of heading data a vessel may be being shown with an inaccurate orientation. If you still feel the display is incorrect, please let us know.