True Wind Speed and Apparent Wind Speed are Showing the Same Speed While the Vessel is Moving

Basic Troubleshooting

If the True Wind Speed (TWS) and Apparent Wind Speed (AWS) are displaying the same speed while the vessel is moving.  It is very likely that the speed sources are not set correctly, have changed, or a device/system is not functioning properly.

• Complete the following items before changing any settings

• If a user changes the settings without ensuring the devices and systems are functioning properly, the original problem may/will still be present

1. 1. Ensure the gWind transducer is not damaged and is moving freely and responding correctly to wind conditions

   2. Ensure the Operational Software is current

   3. If the GND 10 is not showing up in the NMEA 2000 device list

      • Troubleshoot the GND 10

   4. If the GND 10 is showing up in the NMEA 2000 device list, but there is no wind data (AWA / TWA / AWS / TWS)

      • Troubleshoot the NEXUS mast cable and gWind transducer

   5. If the gWind Wireless is not communicating

      • Troubleshoot the gWind wireless wireless connection

   6. If the GST 10 or DST800 / 810 is not on the NMEA 2000 device list

      • Troubleshoot the transducer and NMEA 2000 network

   7. If all devices are present and wind data is present

      • Check and set the "Speed Source" settings

      • See "Speed Source Settings" below

NOTE: The GST 43 is the "Speed and Temperature" transducer (paddlewheel), but the NMEA 2000 will show it as a GST 10.  Because, the GST 10 is the NMEA 2000 gateway between the GST 43 transducer and NMEA 2000 network.

Speed Source Settings

• If the vessels velocity (Speed Source) is not correct, the True wind values and Apparent wind values will be the same on the display

• If the speed sources are set-up wrong, then the speed vector (BSP or SOG) in the formula is not present and the TWS and AWS will show as the same

• A vessel needs at least ONE of these values SOG or (BSP / STW)  for the formula to be complete, allowing the True Wind values to be displayed

• The vessel must select the "Preferred Speed Source" as either a function of SOG or (BSP / STW)  

What is the source that is currently selected?  BSP, STW or SOG

1. If the vessel has a paddle wheel

   • Select the (BSP / STW) as a Speeds Source

   • Set the Preferred source as WIND rather than GPS

2. If the vessel does not have a paddle wheel

   • Select SOG (GPS) as the Speed source

   • Set the Preferred source as SOG (GPS)

• If the vessel does not have a paddle wheel the GPS (SOG) will be the only speed source available

NOTE:  If the vessel has an Autopilot system, do not change the speed sources settings for the Autopilot system.

Definitions and Example

• True Wind Direction (TWD) - The true direction of the wind relative to North

• Apparent Wind Angle (AWA) - The angle of the wind relative to the bow of the vessel

• True Wind Speed (TWS) - The true wind speed relative to the vessel

• Apparent Wind Speed (AWS) - The measured speed of the wind as it is approaching the vessel

• Speed Over Ground (SOG) - This is derived from GPS.  The actual speed of travel, regardless of the power source (wind or motor) or the course steered and any  temporary variations in heading

• Boat Speed (BSP) / Speed Through Water (STW) - This is generally derived from a "Paddle Wheel" transducer.  BSP / STW is the speed of the vessel relative to the vessel travelling through water

• Speed Source - Is a functional setting to allow the system to use either "Speed Over Ground" (SOG) or "Speed Through Water" (STW) to compute the wind values.  Users must decided if they want the speed source computation to be derived from, either the SOG or STW device. Choosing the actual device the user wants to get the information from is found in the "Preferred Sources" page

• Preferred Source - Its a specific "data source"  that supplies information to the display.  Users will select the device the data source is coming from

NOTE: TWS is a calculated value and would give a wind value as if the vessel was not moving. If the vessel is stationary the Apparent Wind and True Wind values are the same.

Example of BSP vs SOG: 

The vessels engine is off and is drifting in the water with a three knot current.

• The vessel will have zero knots BSP / STW, but will have three knots SOG

  • Because the "BSP/STW" source is a Paddle Wheel and the Paddle Wheel is not spinning/moving

  • Conversely, the "SOG" source is GPS and the boat is moving with the three knot current across the face of the Earth

NOTE:  When in the Speed Source is in "Auto" the display will choose the speed source to calculate the True Wind Formula.  The display will first look for a BSP / STW option on the NMEA 2000 data sources as defined in the "Preferred Sources" option.  If no BSP / STW option is found/available, the display will choose and display the "Speed Over Ground" (SOG) for that display.