Dear Friends.
I'm thinking on upgrading my instruments system .
I own a couple of B & G Triton displays and would like to have better information on the true wind direction.
I'm thinking on buying a Maretron SSC300-01 Gyro Compass.
Can anyone tell me if this compass seamlessly integrates with the B&G instruments or do I have to mandatory purchase the RC42N compass from B&G?
I would also like to use the compass with the Expedition software.
Another question is: for the calculation of TWD do I absolutely need a compass or may be sufficient with the COG information obtained from the GPS?
Any help, would be much appreciated.
Kind Regards
Román
Sail or powerboat?
If sailboat, wouldn't you want true wind relative to water?
Hi Dan.
Tanks for you answer.
It's for a racing Sailboat where the historical trend of the last few minutes of the true wind direction is relevant.
Regards
Román
Are you in an area where there are water currents?
Will you also use true wind to understand how your boat is performing, e.g. are your calculating target speed or are you steering to a recommended true wind direction off the port or starboard bow?
It will work. (Planning to do same with H5000 & Hercules to get better specs) How you get N2K data to Expedition to preserve the quality of sensors might be a thing to evaluate. With => 10 Hz sensors for heading, boatspeed, wind angle and wind speed you may find your PC & Network does not keep up.
If you are serious about racing, contemplate that the true wind calculation which can be done in expedition will be more accurate if you can estimate leeway as well. So think about a heel sensor. By the time you have all of those discrete inputs going to the PC, the H5000 Hercules processor and 3D motion sensor with masthead and boatspeed fed to it might be a better start to get calibration of your sensors and calculate a continuous True wind and target angle/vectors from polars. Use the Expedition for analysis, and tactical decisions, let a dedicated processor handle the instrument buffering and signal processing.
For purposes of my answer below, I am going to switch around the terms so I can be clear on which true wind we speak of
Ground Wind = TWD relative to ground, a compass heading as if the boat was anchored and stationary to the ground, is difficult to obtain even a +/- 10 degrees from a moving sailboat. It's hard to even just buy the precision, because what is also needed is a ton of calibration and experience.
Sailors Wind (Ben's term) = TWD relative to water, measured in degrees port or starboard of the bow. Best precision is obtained with a great apparent wind direction and well calibrated speedo, so the apparent wind can be properly calculated. A motion corrected apparent wind is best, using a motion sensor such as offered by B&G WTP3 stablizes the measurement for mast motion, and enables your existing triton displays to show TWS and TWA.
http://www.bandg.com/en-US/Product-Groups/WTP3/
For a lot less money you can obtain a Airmar WX200 weather station that provides really good apparent wind measurement that is stabilized by proprietary algorithms with the assistance of many sensors in the product. The resulting values will also appear on your existing triton displays as TWS and TWA.
https://www.panbo.com/archives/2009/02/sailing_with_an_airmar_pb200_-_part_ii_.html
In regards to SOG/COG, the SOG is entirely useless if there is any current (set & drift) in the water. When SOG > STW, the conversion of AWA to TWA is subject to larger errors. COG also has error, such as leeway.
(THIS CORRECTS MISTAKES IN THE ENTRY ABOVE)
For purposes of my answer below, I am going to switch around the terms so I can be clear on which true wind we speak of
Ground Wind = TWD relative to ground, a compass bearing to the wind as if the boat was anchored fast to the ground, is difficult to obtain even to a +/- 10 degree accuracy from a moving sailboat. To get down to a couple of degrees requires $$$$, a ton of calibration, and experience at the time of measurement to understand if its valid or not (e.g. wind shear).
Sailors Wind (Ben's term) = TWD relative to water the sailboat is moving on, measured in degrees port or starboard of the bow. Some good accuracy is achievable without much calibration or experience. Heading has nothing to do with this measurement. Good precision is obtained with a great AWA source with mast motion correction and well calibrated speedo, as the SAILORS WIND can be properly calculated with only AWA, AWS, and STW. A motion corrected apparent wind is best, using a motion sensor such as offered by B&G WTP3 stabilizes the AWA measurement for mast motion, and enables your existing triton displays to show a smooth TWS and TWA.
http://www.bandg.com/en-US/Product-Groups/WTP3/
For a lot less money you can purchase and Airmar Weatherstation that provides a AWA that is stabilized by proprietary algorithms with the assistance of many sensors in the product. The resulting values will appear on your existing triton displays as TWS and TWA.
https://www.panbo.com/archives/2009/02/sailing_with_an_airmar_pb200_-_part_ii_.html
Note, SOG is generally not a substitute for STW with Sailors Wind, especially if there is any water current (set & drift). When SOG > STW, the conversion of AWA to TWA is subject to larger errors.