Heading sensor and radar

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quantase

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Hi all, I am planning to install a Garmin fantom 24x with hinge mount on a 2022- GW235. I have read that having a heading sensor would be ideal to have overlay on chart. Where on the GW235 should I place the sensor? Does it have to go on the bow or can I place it in storage seating on either port or starboard side as long as it faces forward? Hesitant putting it on the bow since I may place a trolling motor in the future, which would have a magnet. If anyone have pics as well, that would be appreciated.
Thanks.
 
Garmin has several heading sensors that you can use. The SteadyCast sensor, a 9-axis heading sensor unit and a GPS 24xd. They will all provide magnetic compass heading to your chartplotter. SteadyCast is basic heading, 9-axis is top of the line used with autopilot but overkill, GPS 24xd provides heading with enhanced GPS positioning (additional satellite systems).

I have a GPS 24xd installed on my boat. It's installed on the hardtop like a GPS puck. Sensors do not need to be aligned with the physical boat. There are alignment procedures to correct.

Currently replacing my GMR18 with a GMR18 Fantom 40 watt.
 
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my Raymarine flux gate compass is in the first step up to the helm. iirc they have to be centreline and furthest away from as many electronics or ferrous items as possible
 
Fixit said:
my Raymarine flux gate compass is in the first step up to the helm. iirc they have to be centreline and furthest away from as many electronics or ferrous items as possible
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That is the correct placement for autopilot flux gate. They want them low and centerline. The simpler heading sensors have more flexibility where they are mounted. Hardtop or overhead electronic boxes are ok.
 
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I thought the heading sensor was to improve gps heading on the chart for optimal overlay performance.
I’ve had to do figure 8s to calibrate the radar to chart in the past as well.

maybe it is for the radar??? I just know the gyro/ heading sensor works. Get one.
 
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Hookup1 said:
Garmin has several heading sensors that you can use. The SteadyCast sensor, a 9-axis heading sensor unit and a GPS 24xd. They will all provide magnetic compass heading to your chartplotter. SteadyCast is basic heading, 9-axis is top of the line used with autopilot but overkill, GPS 24xd provides heading with enhanced GPS positioning (additional satellite systems).

I have a GPS 24xd installed on my boat. It's installed on the hardtop like a GPS puck. Sensors do not need to be aligned with the physical boat. There are alignment procedures to correct.

Currently replacing my GMR18 with a GMR18 Fantom 40 watt.
Click to expand...
The 24xd seems middle of the road and have flexibility to place on top of hardtop, on bow, or maybe even in locker as long as it’s not close to magnets. Have you used the steady cast prior to the 24xd and notice any major difference?
 
quantase said:
Hi all, I am planning to install a Garmin fantom 24x with hinge mount on a 2022- GW235. I have read that having a heading sensor would be ideal to have overlay on chart. Where on the GW235 should I place the sensor? Does it have to go on the bow or can I place it in storage seating on either port or starboard side as long as it faces forward? Hesitant putting it on the bow since I may place a trolling motor in the future, which would have a magnet. If anyone have pics as well, that would be appreciated.
Thanks.
Click to expand...
A typical GPS calculates heading(based on course over ground) based on movement. It cannot be accurate if you are not moving. It is not accurate enough at all speeds to ensure your radar is displaying the true heading. Your radar would also not be able to track MARPA targets. It can't overlay your chartplotter.

At a minimum you need a Steadycast heading sensor. They provide only heading to the NMEA2k bus. Your radar would also not be able to track MARPA targets. They can be mounted anywhere but must be away from magnets or ferrous metals.

The Garmin GPS24 is their newest N2k gps with a steadycast built in for magnetic heading. But, your new Fantom radar would also not be able to track MARPA targets because also needs your rate of turn in order to calculate target course and speed.

The Garmin 9axis Heading Sensor provides heading, Rate of turn, and roll & pitch(trim & heel). It is more accurate than a Steadycast. Your radar would be able to track MARPA targets.
These are also necessary for an autopilot. If you plan on getting autopilot, get this. But you would save money if you got an autopilot bundle that includes it.


The Garmin MSC10 is a very expensive gps system that can substitute for a 9 axis heading sensor. It is not effected by magnets. It appears that it uses multiple gps antennas spaced apart and calculates heading, roll & pitch from the difference in time between them.
 
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Heading Sensor Recommendation for use with Garmin Chartplotters | Garmin Customer Support

Garmin Support Center is where you will find answers to frequently asked questions and resources to help with all of your Garmin products.
support.garmin.com support.garmin.com

Heading Sensor Recommendation for use with Garmin Chartplotters​

Garmin recommends that customers use a heading sensor with a Garmin chartplotter. Garmin offers a few different options for heading sensors to be connected to the chartplotter over a NMEA 2000 network. Click on the link below for information about each specific heading sensor:
By adding a heading sensor, the chartplotter will have the ability to provide a true heading at all times. Without a heading sensor, the chartplotter will rely on a GPS heading (COG) which will only be accurate when the boat is moving. With GPS heading only and while the boat is not moving, the chartplotter will be unable to determine its true heading.
If a Garmin Radar is being used with the chartplotter, and the heading sensor is added, the chartplotter can now use MARPA (mini-automatic radar plotting aid), which helps to avoid collisions.
 
One further option, if you have an auto pilot system with a heading sensor such as a flux gate magnetic compass, on a NMEA 0183 bus, it will also provide heading information to your radar and allow for the use of MARPA. My older Raymarine autopilot has a fluxgate compass, speaks to my dual 1243xsv MFDs via NMEA 0183 and allows my Fantom Garmin radar to provide MARPA info.
 
quantase said:
The 24xd seems middle of the road and have flexibility to place on top of hardtop, on bow, or maybe even in locker as long as it’s not close to magnets. Have you used the steady cast prior to the 24xd and notice any major difference?
Click to expand...
SteadyCast and the GPS24xd use the same heading sensor internals. I bought a SteadyCast but returned it before installing it. I put the 24xd in instead. I wanted the better GPS and I preferred mounting the heading sensor on the hardtop. It’s good enough for MARPA use.
 
Hookup1 said:
SteadyCast and the GPS24xd use the same heading sensor internals. I bought a SteadyCast but returned it before installing it. I put the 24xd in instead. I wanted the better GPS and I preferred mounting the heading sensor on the hardtop. It’s good enough for MARPA use.
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I saw conflicting information on Garmin site in descriptions of Steadycast vs the full blown 9 axis heading sensor (AP heading sensor)
SteadyCast
  • Ensures bow orientation on your chartplotter matches your heading
  • Heading accuracy of plus or minus 3 degrees
  • Easy NMEA 2000® plug-and-play interface
  • Simple 2-step calibration process
  • 9-axis MEMS technology allows installation in any orientation located away from magnetic interference
SteadyCast heading sensor is a simple, easy-to-install solution that provides fast calibration and premium heading accuracy. It aligns your boat bow to its actual orientation so you know where you are casting according to your chartplotter screen.
it doesn't specify that it does or doesn't work with MARPA.

The more expensive 9 axis Heading Sensor;

Premium Solution for Exceptional Heading Accuracy​

  • Provides exceptional heading accuracy, even at lower speeds or when bow is pitching, rolling or heeling over
  • Heading accuracy of plus or minus 2 degrees
  • Heading and rate-of-turn output at 10 Hz; trim and heel output at 1 Hz
  • Simple 2-step calibration process
  • 9-axis MEMS technology allows installation in any orientation located away from magnetic interference
The 9-axis heading sensor is our premium solution that is easy to install and provides fast calibration and exceptional heading accuracy.

Accurate Heading Even at Low Speed​

Its heading output at 10 Hz and accuracy of plus or minus 2 degrees ensures your chart orientation and boat heading line match up with reality, even at lower speeds. It also allows for MARPA tracking and improves radar overlay experience.

I have one of these as part of my AP and it works fully with my Fantom radar
 
MARPA probably works with GPS generated heading as long as you are moving (don't trust though). I'm not sure that MARPA needs any more information than heading. MARPA targets are further out. Nice to have but stopped close quarters maneuvering is more important to me.

I have been in situations around a bridge in the fog with commercial fishing traffic and significant current without even a simple heading sensor. Couldn't see the bridge, channel or the traffic. The current would spin you around in an instant and you had no idea it happened. Very dangerous.

I think simple heading sensors are a big safety improvement for a stopped or slow moving boat. As long as the chartplotter sync's with the front of the boat I'm happy - particularly if I'm slow or stopped.
 
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Hookup1 said:
MARPA probably works with GPS generated heading as long as you are moving (don't trust though). No, it won't.I'm not sure that MARPA needs any more information than heading. Yes, it does. It is calculating (and displaying) target position(range and bearing), speed and course by comparing it to your own. It needs to know your speed and COG and Heading and know if you are turning. MARPA targets are further out. Nice to have but stopped close quarters maneuvering is more important to me. MARPA isn't very useful to a small boat with the helmsman operating the boat and also trying to operate the radar and chartplotter...in the dark or fog... or when bobbing in the waves.... MARPA is really for "ships" to track potential crossing targets. I've tried to use it and it isn't easy to pay attention and manipulate the menus while driving the boat. Without Autopilot forget it. You are better off taking a glimpse at the radar and then using your eyes out front. Of course, once you have a MARPA track on, it keeps a symbol on it and makes it easier to see.

I have been in situations around a bridge in the fog with commercial fishing traffic and significant current without even a simple heading sensor. Couldn't see the bridge, channel or the traffic. The current would spin you around in an instant and you had no idea it happened. Very dangerous.

I think simple heading sensors are a big safety improvement for a stopped or slow moving boat. As long as the chartplotter sync's with the front of the boat I'm happy - particularly if I'm slow or stopped. AGREE
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I was a Firecontrolman in the Navy in the 1980s. MK86 5" gun system. I spent 4 years staring at tracks in all hours of the day & night in places 99.9% of all human beings living or dead have never been. Our equipment filled rooms and cost million$.. It is amazing what today's consumer electronics can do.
 
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SkunkBoat said:
I was a Firecontrolman in the Navy in the 1980s. MK86 5" gun system. I spent 4 years staring at tracks in all hours of the day & night in places 99.9% of all human beings living or dead have never been. Our equipment filled rooms and cost million$.. It is amazing what today's consumer electronics can do.
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Military stuff is really cool. Eventually that technology leaks out into the recreational market.

For my use case MARPA is best for long runs offshore. I Don't do that on my boat. I do that kind of fishing on larger boats. But the new unit has it. It is truly amazing what has happened in the recreational boater segment of the market. In 1995 when I started saltwater fishing I had a PC for navigation (NavTrek). I traveled all over with it and people were blown away. We would fish reef edges in the Bahamas alongside experienced captains who couldn't understand how we could stay on the edge (Dutch Bar, Eleuthera) with no experience there. Same with Chubb Cay in the Pocket. Or crossing the bank.

The issue today is over reliance on technology. When I bought my boat in 1995 I went t a USCG boating safety course with my 2 boys. We learned to navigate with paper charts. Set and drift. Rules of the road, navigation markers and forward and reverse ranges. Too many people are lost without electronics.

I'm waiting for the Omni scanning sonar technology to find its way into the recreational market. $250k is a little more than I can afford by at least 2 zero's.
 
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Great info! So it sounds like if I want to utilize MARPA, go with MSC10. Anyone have a pic where they mounted their MSC10? If MARPA is not a concern but want good heading, go with the 24xd instead of 9axis.
 
I'm not sure you need the 9 axis heading sensor. Read Garmin's response in my post above. I do not have my boat in the water right now so I can't confirm that you will get MARPA with SteadyCast or GPS 24xd but Garmin says you will.
 
9 axis - wow. In my inertial navigation days it was three roll, pitch and yaw. I guess I'm getting old!
 
Hookup1 said:
My guess is the autopilot needs more realtime information...
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Technically, its an Inertial Measurement Unit. By "9" axis they mean its a combination gyroscope,accelerometer, and magnetometer.
So it doesn't just sense the angles it senses the rate of change also. Its all on a chip. You have the same type of thing in your phone and Fitbit
The steadycast is acting as a magnetometer
I suspect, not sure, that the steadycast and the AP sensor have the same "sensor" but the AP version adds circuitry to calculate more things and put them out on N2k in the proper "words".

I suspect they are terribly overpriced because they are sold to boat owners. Pretty sure about that....
 
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