SAILMON MAX

5X-MOANA

Member
212
8
SF no more
Love my Sailmon MAX!
... but it could be so much more than a fancy display. Two ideas which would use its WiFi and BT capabilities:

1) Support BT connection to Smartwatches which can then be used as remote (many mounting locations in dinghies do not allow pressing any buttons on the MAX)

2) Add coach&voice mode by programming a BT - WiFi audio bridge: Sailor has waterproof BT earset, audio comes via BT from MAX which receives it via WiFi from the coach boat which has a similar setup. Bonus points for a nice UI on the coach boat, so coach can choose which boats hear his communication.
Coach also receives live GNSS/IMU data from the boats and can compare it live between two boats he is coaching. Not to be used while racing, of course.
Not sure if this is really possible with the current HW (WiFi RF/antenna my be to poor, battery too small), but something to consider for MAX2.

 
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Roleur

Super Anarchist
2,910
601
Orcas Island
Am I missing something?  For starting, is there no way to add the GPS offset from the bow?  If there is, bugger me, if I can figure it out.

 

flyinggorilla

New member
44
42
Austria


I was always wondering how accurate the TWS calculation of the Sailmon Max and Calypso Ultrasonic Anemometer is. So far the live VMG calculations seems still odd, especially upwind. I am wondering if anyone has figure out or found a documentation on how to best set the correction values if those help at all. (the documentation doesnt reveal how to best set correction values: UPWIND TWA CORRECTION: enter a value in degrees between -90 and 90. DOWNWIND TWA CORRECTION: enter a value in degrees between -90 and 90. DOWNWIND TWS CORRECTION: enter a percentage between 0 and 120. )

So as to my test run, ....

I could make good use of a broken carbon tiller extension (I broke it here https://youtu.be/ekj2gHQPFg4) to create a mount for the Calypso Ultrasonic Anemometer in approx 2m height at the forestays. This should provide better reading than with the previous mount at approx 1m given wind-sheer has biggest impact first 2m from water surface. I still think there is some calibration/correction needed and wonder what's your thought and experience is about TWS and VMG accuracy from Sailmon Max + Calypso Utrasonic. The goal is to create polars and better VMG information, once the data can be deemed as accurate enough. Btw. this gave me an opportunity to mount the GoPro at 2m height as well, providing a new perspective and a better view for reviewing the dos and dont's.

Ultimately the goal of this setup is to train for optimizing VMG. Also I plan to create polar diagrams as input for an updated version of the sail trim simulator that lacks forces and speed suggestions based on real-world polars. 

About the Calypso / GoPro mount: Except for the carbon rod, the mount is 3D printed (model is here: https://a360.co/3yKjw8c). The electronics and software for the Weather buoy are open source and can be found here: https://github.com/flyinggorilla/weat...

20210829_120229685_iOS (2).jpg

 
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JonRowe

Super Anarchist
1,804
961
Offshore.
I'm keen to add a wind sensor to my max as a backup to my masthead wand so interested in your thoughts on calibration (also that weather buoy is cool) any reason why you didn't go masthead yourself? My understanding is calibration is always going to be harder the lower it is, and that ultrasonic sensors are not the most accurate to begin with?

 

flyinggorilla

New member
44
42
Austria
New Video: A-Class catamaran foiling Video with Sailmon Max and Calypso Ultrasonic Anemometer and Telemetry Overlay. In below picture you can see the cross bar at approx 2m height mounted at the forestay. The video below shows the wind data taken from there.

sideshot rocketing.jpg




 
On 10/5/2021 at 6:11 AM, flyinggorilla said:

New Video: A-Class catamaran foiling Video with Sailmon Max and Calypso Ultrasonic Anemometer and Telemetry Overlay. In below picture you can see the cross bar at approx 2m height mounted at the forestay. The video below shows the wind data taken from there.

View attachment 466129


@flyinggorilla I love your videos and also your openness to sharing your 3D printing files.  The ways you capture the onboard action from different cameras is truly ingenious. 
 

A few questions:

- Any thoughts on how accurate the Calypso sensor is? (for apparent wind measurement)

- How about the accuracy of the Sailmon Max true wind data calculations?  You mentioned VMG was a bit strange, so I imagine TWA/TWS is also imperfect.  Have you seen significant differences comparing TWS/TWD for example before/after a tack, or between upwind/downwind? (If the data is poor quality it should show up clearly in a strip chart of TWS/TWD when you tack or change modes). 

- Your video now shows the Sailmon Max fitted in a fixed position instead of on the auto-tacking mount (on the mast rotation arm) you showed in a previous video. What motivated you to go back to a fixed mount?

Pretty keen to try the A Class after seeing your videos!

 

flyinggorilla

New member
44
42
Austria
@galacticair thanks, glad you find it helpful.

as to your questions:

- Any thoughts on how accurate the Calypso sensor is? (for apparent wind measurement)

[SIZE=10.5pt]The accuracy is dependent on where the sensor is mounted. On the A-Cat I don’t have that many possibilities, so mounting it at about 2m height in-between the forestays seems to be the best compromise of airflow impact by sail and height relative to wind-sheer effects. However the effects are significant, see below.[/SIZE]

- How about the accuracy of the Sailmon Max true wind data calculations?  You mentioned VMG was a bit strange, so I imagine TWA/TWS is also imperfect.  Have you seen significant differences comparing TWS/TWD for example before/after a tack, or between upwind/downwind? (If the data is poor quality it should show up clearly in a strip chart of TWS/TWD when you tack or change modes). 

[SIZE=10.5pt]My ultimate goal of optimizing Velocity Made Good (VMG) by instruments is not yet achieved. Also deriving polar diagrams based on this data is too far off. The influence of the sail to the airflow in front of the mast – where the calypso is mounted – is too large for reasonable accuracy. The upwash of the airflow around the sail causes true wind tacking. This means that even if the wind direction is constant, in front of the sail there is so called upwash which means that airflow changes direction impacting instruments. Sailmon Max has a correction factor for True Wind Angle (TWA). However, this is not yet practical as the correction factor depends on the True Wind Speed (TWS). Sailmons larger device has a correction table for various wind-speeds. Implementing such in Sailmon Max was my initial suggestion too. However, I was told they are looking at a potential easier to use solution to this, for varying wind-speeds and upwind/downwind. However, right now, without a proper correction table, it is just not there yet. [/SIZE]

[SIZE=10.5pt]If you still want to try the current TWA compensation then you can do this with following steps:[/SIZE]

  • [SIZE=10.5pt]Display TWD on sailmon max going upwind. E.g. it display 180 degrees[/SIZE]
  • [SIZE=10.5pt]Tack and check TWD again, e.g. it displays 160 degrees[/SIZE]
  • [SIZE=10.5pt]The mid of both angles is 170 degrees, so measured angles are +/- 10 degrees off[/SIZE]
  • [SIZE=10.5pt]In the Sailmon Max under menu->system->sensor->wind->upwind TWA this can be corrected by e.g. -10 degrees.[/SIZE]
  • [SIZE=10.5pt]Same can be done downwind, and at various wind speeds[/SIZE]

- Your video now shows the Sailmon Max fitted in a fixed position instead of on the auto-tacking mount (on the mast rotation arm) you showed in a previous video. What motivated you to go back to a fixed mount?

[SIZE=10.5pt]The reason I moved back to fixed Sailmon Max is because Sailmon uses built-in compass and not the Calypso Ultrasonic compass. This means auto-tacking causes wrong TWA calculations. If there was an option in Sailmon Max to use calypso compass for those calculations, I would switch back to auto-tacking as this is easier to read, especially once real-time VMG display will be accurate enough.[/SIZE]

[SIZE=10.5pt]However, if you don’t use an anemometer with Sailmon Max then you can rely on Course Over Ground (COG) for boat heading instead of compass, making use of auto-tacking practical enough.[/SIZE]

-FG

 
[SIZE=10.5pt]The accuracy is dependent on where the sensor is mounted.[/SIZE]



[SIZE=10.5pt]My ultimate goal of optimizing Velocity Made Good (VMG) by instruments is not yet achieved. Also deriving polar diagrams based on this data is too far off. The influence of the sail to the airflow in front of the mast – where the calypso is mounted – is too large for reasonable accuracy… Sailmon Max has a correction factor for True Wind Angle (TWA). However, this is not yet practical as the correction factor depends on the True Wind Speed (TWS)… However, I was told they are looking at a potential easier to use solution…[/SIZE]



[SIZE=10.5pt]The reason I moved back to fixed Sailmon Max is because Sailmon uses built-in compass…[/SIZE]
Thank you FG, very instructive. Sounds like you are facing all the same calibration issues as bigger boat systems, with even more constraints (eg sensor positioning).
 

Would be interesting to see if Sailmon could simplify the calibration using some simple auto calibration routines (eg sail upwind for 5min, tack 3 times… I think B&G had this). Then either apply an estimated correction factor for downwind modes, or repeat calibration downwind…. Could at least be better than zero calibration…

Understood on display mounting. I figure that for most A-class speeds, COG is accurate enough (compared to magnetic heading) so the tacking mount makes sense, until you need heading input for other calcs like TWD. Some bigger systems allow setting COG as heading input for TWD calculators, so I wonder if that would bypass reliance on HDG?

 
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Rohanoz

Super Anarchist
Question on using the Header/Lift field - how does this calibrate?

Does it 'self assign' an average angle after a period of time? How long?  

Or, do you manually need to set the wind angle at some point to get it to Work?

 

flyinggorilla

New member
44
42
Austria
I created a little webapp to view Sailmon MAX data as Polar diagram. You can upload your own Sailmon MAX csv files as well (it must include TWA/TWS wind data such as from Calypso Ultrasonic wind sensor). 

It helps to correct the Calypso mount angle which i found on my data to be off 10 to 20 degrees, causing obviously live data during sailing also be off.

Ideally these polars help with VMG analysis. Note that you can select/deselect TWS speeds in the legend, so to view SOG/TWA for certain TWS speeds. I hope that Sailmon comes up with an improved TWA correction this coming season, that should make also such polars and VMG analysis more accurate.

Atterwind.info Sailmon Max Polar Diagrams

image.png

this polar is a result from this sailing session: 




 

Mozzy Sails

Super Anarchist
1,150
931
United Kingdom
What sort of angles can the screen be read from? Any chance at seeing a fixed mast mounted screen from the wire? 

I really want to use magnetic heading rather than COG as we have so much tide and its so variable across the course it would really screw with perception of shifts using COG. 

Also, will heel still work with a tacking mount?

 

JonRowe

Super Anarchist
1,804
961
Offshore.
What sort of angles can the screen be read from? Any chance at seeing a fixed mast mounted screen from the wire? 

I really want to use magnetic heading rather than COG as we have so much tide and its so variable across the course it would really screw with perception of shifts using COG. 

Also, will heel still work with a tacking mount?
Its an e-ink display its pretty readable at very wide angles, how wide is your wire to mast eyeline? It supports shift detection in "no gps" mode and defo does magnetic heading, but not sure if shift detection always uses it (I'd assume it would but you know the saying about assume) (of course you could always just use the mk1 eyeball on the heading for shift detection).

One annoying thing is that track downloading is about to become a premium feature via the £10/month gold version of the app (the currently free app supports csv export but apparently thats going to be a premium feature)

 
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Mozzy Sails

Super Anarchist
1,150
931
United Kingdom
I think upwind the helm is anywhere from 60 to 90 degrees. The crew obviously further forward still. 

But basically need something with 180 degrees...

£10 for download is a bit annoying. Paying to take your own data from their ecosystem isn't that cool. I would want to be taking the data over to Njord to overlay, which is already a subscription.

I mean, if they produced their own software which did video overlay and then charged £10 a month then fine.

I see they have a new device coming out which records only, wonder if that will be the same for that? 

 

JonRowe

Super Anarchist
1,804
961
Offshore.
I'd say the max is more than 90 degrees of visual, estimating from playing around with angle more like up to 150/160? Its visible right up until almost when you'd lose sight from the angle of the display anyway If you're down in Hamble some time I'd happily demo mine!

 

Mozzy Sails

Super Anarchist
1,150
931
United Kingdom
I'd say the max is more than 90 degrees of visual, estimating from playing around with angle more like up to 150/160? Its visible right up until almost when you'd lose sight from the angle of the display anyway If you're down in Hamble some time I'd happily demo mine!
sorry, meant 90 degrees off dead on. So, I'd need a 180 degree cone of visibility. Basically, in light winds the helm is pretty much in line with mast and the crew in front. 

Typical medium wind position shown below, so even then the crew would need almost 180 degree.

viewing angle.jpg
 

 
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Roleur

Super Anarchist
2,910
601
Orcas Island
Has anyone succeeded in getting Cyclops load cell data on their Sailmon Max?  I updated the Sailmon software. I can see the new Load1 field. I can connect to the Cyclops WiFi network, but no data shows up on the Max.  When I connect my phone to the Cyclops WiFI that works fine.  

Anyone?

 

crashtack

Member
483
349
Max & ProStart owners - is the Max (without the anemometer) worth getting as a replacement to the ProStart? Or is it not enough of a difference?

 
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