Good Service In Marmaris Turkey


svperegrinus@yahoo.com
 

Bill,

We have the same B&G AC42, using a Victron DC-DC converter from 24V to 12V for the clutch.  A great installation since 2014.

What autopilot mode or setting is it that optimizes VMG when close-hauled?  I seem to have missed that on the manual!

Thanks in advance,

Peregrinus
SM2K N. 350
en route to Chalcis (Negropont)


greatketch@...
 

Yes, a 24 ->12 volt convertor will certainly work.  The advantages of the resistor are fewer parts (one!) and it cost $2.80--for a package of two.

I do not know how consistent the menu trees are for different MFDs, but here is where that option lives on on our Zeus touch:

Push "Page"-> Go to "Settings" -> Select "Autopilot" -> Select "Sailing"

From the resulting popup window, turn on "VMG optimizing".

I do not think this is in the manual for the autopilot computer at all. You have to go to the manual for the device (or devices) you use to control it.

I know it can also be selected from the Triton display, but I don't remember that menu list because I hardly ever use it...

Bill Kinney
SM160, Harmonie
Bar Harbor, Maine.


---In amelyachtowners@..., <svperegrinus@...> wrote :

Bill,

We have the same B&G AC42, using a Victron DC-DC converter from 24V to 12V for the clutch.  A great installation since 2014.

What autopilot mode or setting is it that optimizes VMG when close-hauled?  I seem to have missed that on the manual!

Thanks in advance,

Peregrinus
SM2K N. 350
en route to Chalcis (Negropont)


Paul Osterberg
 

Do you use the B&G AP with the old Raymarine driveunits?
We thinking of buying the Raymarine EV 400 system as main AP and use the old Autohelm as back up.
Probably also changing the instrumentation to Raymarine all over as my sonic speed stoped working and guess difficult get spare parts and probably running towards it,s end anyhow.
Anyone with experience with the RAYMARINE EV 400 system and can give pro and cons? Compared with the B&G system
Paul on SY Kerpa SM259


greatketch@...
 

Paul,

Even though we have B&G brand instruments for most things, our system looks very little like the original 1990's electronics that came with our boat when we bought her.  

The original Hydra unit is kept primarily to act as an interface between the mast head wind instrument and everything else.  

The more sophisticated of our original Autohelm autopilots we kept installed as a back up.  Both drive units are the original Autohelm drives (chain drive to the wheel/linear drive to the quadrant).  We can run either AP computer to either AP drive.  The voltage of the clutch is the only fly in that ointment, but it is not hard to fix.

We still have the original B&G analog gauges for Wind speed, and Wind direction, but find the display on the digital Triton units which have True wind angle and True wind speed as well as Apparent wind angle and speed pretty much make the old B&G units second tier.  I know some people swear by these old analog gauges, but they don't do much for me.

Right now we have two Tritons to display data, and a 12" Zeus Touch as a primary display.  Almost all data (except for the mast head wind info) is on the NMEA2000 bus, and the NMEA0183 data has almost gone away.  Our most recent update is adding the B&G 3G radar when the old Furuno 1831 died.  It is very nice having a radar display at the helm station instead of below!

Bill Kinney
SM160,  Harmonie
Bar Harbor, Maine.


svperegrinus@yahoo.com
 

Paul,

We kept the old Raymarine T-300 and associated ST7001+ control head.  We have two rotary switches which let us choose which autopilot to engage (B&G or Raymarine), and which drive (rotary or linear).

I haven't used the latest Raymarine stuff, so I don't know about pros and cons.  

All I can tell you from personal experience and from stuff I have read: don't buy this year's product series.  Buy last year's!  Generally the stuff that just came out does not have the best software.  Whereas if you buy whatever your manufacturer of choice started shipping about 12 months ago, you will be getting stable, reliable software that has been tested and debugged thanks to the other customers who bought the latest and greatest.

But don't buy stuff that came out more than 18 months ago, because then you will only get support for a limited window of time before it is discontinued and support becomes minimal to nonexistent.

Cheers,

Peregrinus
SM2K Nr. 350 (2002)
At anchor, Eretria


svperegrinus@yahoo.com
 

Bill Kinney,

I checked the box in "Autopilot > Sailing > VMG Optimizing".  Thanks for the tip!

Now, for this to work one must designate a waypoint to navigate to and activate "Wind Navigation", correct?

I tried it this morning as we sailed upwind and it worked fine for about 1/2 hr holding a great course, until wind changed suddenly and dropped at the same time —welcome to the Med— and the autopilot let the boat do an "accidental tack," i.e., we got the genoa reversed all of the sudden.  We purposefully let it mess up, of course, to to see how smart the thing is.

Looks like we will be using this function a lot in the future, I just want to make sure I'm doing it correctly!  We have a Zeus 12 and a Zeus2 7.

Best,


Peregrinus
SM2K #350
At anchor, Calcidia (Negroponte)




---In amelyachtowners@..., <greatketch@...> wrote :

Yes, a 24 ->12 volt convertor will certainly work.  The advantages of the resistor are fewer parts (one!) and it cost $2.80--for a package of two.

I do not know how consistent the menu trees are for different MFDs, but here is where that option lives on on our Zeus touch:

Push "Page"-> Go to "Settings" -> Select "Autopilot" -> Select "Sailing"

From the resulting popup window, turn on "VMG optimizing".

I do not think this is in the manual for the autopilot computer at all. You have to go to the manual for the device (or devices) you use to control it.

I know it can also be selected from the Triton display, but I don't remember that menu list because I hardly ever use it...

Bill Kinney
SM160, Harmonie
Bar Harbor, Maine.


---In amelyachtowners@..., <svperegrinus@...> wrote :

Bill,

We have the same B&G AC42, using a Victron DC-DC converter from 24V to 12V for the clutch.  A great installation since 2014.

What autopilot mode or setting is it that optimizes VMG when close-hauled?  I seem to have missed that on the manual!

Thanks in advance,

Peregrinus
SM2K N. 350
en route to Chalcis (Negropont)


greatketch@...
 


Yes, the AP needs to be in "Wind" mode for VMG optimization to work.  If you are steering a compass course all the information about wind angle is ignored.

Bill Kinney
SM160, Harmonie
Underway, Bar Harbor, heading south.

---In amelyachtowners@..., <svperegrinus@...> wrote :

Bill Kinney,

I checked the box in "Autopilot > Sailing > VMG Optimizing".  Thanks for the tip!

Now, for this to work one must designate a waypoint to navigate to and activate "Wind Navigation", correct?

I tried it this morning as we sailed upwind and it worked fine for about 1/2 hr holding a great course, until wind changed suddenly and dropped at the same time —welcome to the Med— and the autopilot let the boat do an "accidental tack," i.e., we got the genoa reversed all of the sudden.  We purposefully let it mess up, of course, to to see how smart the thing is.

Looks like we will be using this function a lot in the future, I just want to make sure I'm doing it correctly!  We have a Zeus 12 and a Zeus2 7.

Best,


Peregrinus
SM2K #350
At anchor, Calcidia (Negroponte)




---In amelyachtowners@..., <greatketch@...> wrote :

Yes, a 24 ->12 volt convertor will certainly work.  The advantages of the resistor are fewer parts (one!) and it cost $2.80--for a package of two.

I do not know how consistent the menu trees are for different MFDs, but here is where that option lives on on our Zeus touch:

Push "Page"-> Go to "Settings" -> Select "Autopilot" -> Select "Sailing"

From the resulting popup window, turn on "VMG optimizing".

I do not think this is in the manual for the autopilot computer at all. You have to go to the manual for the device (or devices) you use to control it.

I know it can also be selected from the Triton display, but I don't remember that menu list because I hardly ever use it...

Bill Kinney
SM160, Harmonie
Bar Harbor, Maine.


---In amelyachtowners@..., <svperegrinus@...> wrote :

Bill,

We have the same B&G AC42, using a Victron DC-DC converter from 24V to 12V for the clutch.  A great installation since 2014.

What autopilot mode or setting is it that optimizes VMG when close-hauled?  I seem to have missed that on the manual!

Thanks in advance,

Peregrinus
SM2K N. 350
en route to Chalcis (Negropont)


Craig Briggs
 


Hi Bill,.
I think you meant the AP should be in Wn (Wind Navigate) mode, not just W (Wind) mode, right?
Cheers, Craig SN#68 Sangaris, sailing in Wn mode off NJ coast with waypoint to Sandy Hook.

---In amelyachtowners@..., <greatketch@...> wrote :


Yes, the AP needs to be in "Wind" mode for VMG optimization to work.  If you are steering a compass course all the information about wind angle is ignored.

Bill Kinney
SM160, Harmonie
Underway, Bar Harbor, heading south.

---In amelyachtowners@..., <svperegrinus@...> wrote :

Bill Kinney,

I checked the box in "Autopilot > Sailing > VMG Optimizing".  Thanks for the tip!

Now, for this to work one must designate a waypoint to navigate to and activate "Wind Navigation", correct?

I tried it this morning as we sailed upwind and it worked fine for about 1/2 hr holding a great course, until wind changed suddenly and dropped at the same time —welcome to the Med— and the autopilot let the boat do an "accidental tack," i.e., we got the genoa reversed all of the sudden.  We purposefully let it mess up, of course, to to see how smart the thing is.

Looks like we will be using this function a lot in the future, I just want to make sure I'm doing it correctly!  We have a Zeus 12 and a Zeus2 7.

Best,


Peregrinus
SM2K #350
At anchor, Calcidia (Negroponte)




---In amelyachtowners@..., <greatketch@...> wrote :

Yes, a 24 ->12 volt convertor will certainly work.  The advantages of the resistor are fewer parts (one!) and it cost $2.80--for a package of two.

I do not know how consistent the menu trees are for different MFDs, but here is where that option lives on on our Zeus touch:

Push "Page"-> Go to "Settings" -> Select "Autopilot" -> Select "Sailing"

From the resulting popup window, turn on "VMG optimizing".

I do not think this is in the manual for the autopilot computer at all. You have to go to the manual for the device (or devices) you use to control it.

I know it can also be selected from the Triton display, but I don't remember that menu list because I hardly ever use it...

Bill Kinney
SM160, Harmonie
Bar Harbor, Maine.


---In amelyachtowners@..., <svperegrinus@...> wrote :

Bill,

We have the same B&G AC42, using a Victron DC-DC converter from 24V to 12V for the clutch.  A great installation since 2014.

What autopilot mode or setting is it that optimizes VMG when close-hauled?  I seem to have missed that on the manual!

Thanks in advance,

Peregrinus
SM2K N. 350
en route to Chalcis (Negropont)


greatketch@...
 

No, "W" wind only mode works fine for the VMG optimization.  

I rarely use the "Wind Navigation" mode, and I am not sure exactly how VMG optimization would work there.

Bill Kinney
SM160, Harmonie
Gloucester, Mass


svperegrinus@yahoo.com
 

Bill Kinney, I'm with Craig on this: I understand how VMG optimization works on Wind Navigation.  

I fail to see, however, how it might work on mere "W".  What would it optimize to, if it does not now where I intend to go to?  

Having said that, yesterday afternoon (1st day ever after checking the "VMG Optimization" checkbox), my wife the Admiral was W sailing... plain W-autopilot sailing you see, and the thing did what you described: it actually changed my wife's designated angle, one degree at at time.  But we are not clear on what exactly the autopilot thinks it was doing.  Surely there is a reason.

Best,


Peregrinus
SM#350
At anchor, Thermopylae






---In amelyachtowners@..., <greatketch@...> wrote :

No, "W" wind only mode works fine for the VMG optimization.  

I rarely use the "Wind Navigation" mode, and I am not sure exactly how VMG optimization would work there.

Bill Kinney
SM160, Harmonie
Gloucester, Mass


Alan Leslie
 

It was keeping a constant angle to the wind.
To do that it has to continually change the heading of the boat to keep the wind to heading angle constant.
This mode is great for passage making as the sails don't need constant attention.
The course is not constant, it varies with the wind direction.
If you have a constant heading or have a waypoint that the pilot is steering to, and the wind direction changes, you need to adjust the sails.....and sometimes you may not be able to and end up in irons or involuntarily gybing.
Cheers
Alan
Elyse SM437


greatketch@...
 

It definitely works in W(ind) mode.  What it is doing is finding the wind angle that will make the boat reach an imaginary waypoint directly to windward, as fast as possible. The VMG it is optimizing is the VMG to windward, NOT the VMG to the next navigation waypoint.

I know the manual gives very little to this function, but what it says (in total!) is "You can optimize the VMG to the wind. When selected the function will be active for 5-10 minutes after a new wind angle has been set and only when beating."

The assumption here is that if you are beating, then your desired destination must be to windward of your location. It actually doesn't matter for the optimization if that destination is directly to windward, as long as it is somewhere in the cone between the boat's tacking angles.

Note that the optimization in not continuous.  It works until it is finds an optimum that meets its criteria (what ever that is!), and then holds that wind angle.  If conditions change, such as wind strength or wave size, it is a good idea to command the unit to make a small change in course so it re-runs the optimization program.

As I said, I rarely use Wn (Wind Navigation) mode on my system, so I have little experience with how the VMG Optimization function works there, but based on what I understand about the Wn mode works, the VMG function wouldn't actually do anything

The optimized wind angle will always produce a speed through the water a bit slower than you could get if you bore off just a few degrees. Using the simplest possible analysis, if you are sailing 6 knots at a True Wind Angle of 55 degrees, anything better than 5.5 knots will give a better VMG at 49 degrees TWA

I do not know if this function uses only speed through the water and true wind angle for it's calculation, or if it adds in course and speed over ground.  I emailed B&G's tech support asking that question, but never got an answer.

Bill Kinney
SM160, Harmonie
Gloucester, Mass


svperegrinus@yahoo.com
 

Bill,

Thanks for the detailed explanation.  My only remaining question is if under "W", the autopilot is trying to optimize VMG to an Apparent Wind Angle AWA of zero, or is it trying to optimize to a shallower angle, say, 10° or 20°.  It seems to me that optimized VMG is not the same to a destination that is {0°, 10°, 20° or 30°} AWA of one's current position.

When under autopilot, we sail in "Wind" mode most of the time by far, so we'll try in the weeks and months ahead to see what we can learn of the VMG algorithm the B&G autopilot uses.  The only problem is that we try and avoid beating like the plague, so it may take a while to accumulate observations on VMG-optimization.

Cheerio,

Peregrinus
SM2K N. 350
at anchor, Thermopylae



---In amelyachtowners@..., <greatketch@...> wrote :

It definitely works in W(ind) mode.  What it is doing is finding the wind angle that will make the boat reach an imaginary waypoint directly to windward, as fast as possible. The VMG it is optimizing is the VMG to windward, NOT the VMG to the next navigation waypoint.

I know the manual gives very little to this function, but what it says (in total!) is "You can optimize the VMG to the wind. When selected the function will be active for 5-10 minutes after a new wind angle has been set and only when beating."

The assumption here is that if you are beating, then your desired destination must be to windward of your location. It actually doesn't matter for the optimization if that destination is directly to windward, as long as it is somewhere in the cone between the boat's tacking angles.

Note that the optimization in not continuous.  It works until it is finds an optimum that meets its criteria (what ever that is!), and then holds that wind angle.  If conditions change, such as wind strength or wave size, it is a good idea to command the unit to make a small change in course so it re-runs the optimization program.

As I said, I rarely use Wn (Wind Navigation) mode on my system, so I have little experience with how the VMG Optimization function works there, but based on what I understand about the Wn mode works, the VMG function wouldn't actually do anything

The optimized wind angle will always produce a speed through the water a bit slower than you could get if you bore off just a few degrees. Using the simplest possible analysis, if you are sailing 6 knots at a True Wind Angle of 55 degrees, anything better than 5.5 knots will give a better VMG at 49 degrees TWA

I do not know if this function uses only speed through the water and true wind angle for it's calculation, or if it adds in course and speed over ground.  I emailed B&G's tech support asking that question, but never got an answer.

Bill Kinney
SM160, Harmonie
Gloucester, Mass


greatketch@...
 

While I was writing that last post I had to stop and convince myself that a course optimized to a point dead upwind would be the same as a course optimized to a point that was, say 25 degrees off the wind.  After drawing a few vector diagrams, I managed to convince myself that the optimization would give the same result to either course. (Note well: convincing myself is NOT the same as a proof. I could be wrong!)

Here is my logic... While sailing up wind I can break my velocity vector into two component vectors:  one straight upwind, and the other perpendicular to that.  Any useful optimization program must maximize the upwind velocity vector and minimize the cross wind vector.  No matter where my destination is in the upwind zone (between the tack angles) the vector perpendicular to the wind is taking me away from where I want to go, so minimizing that is always best.  QED.  (Maybe)

And I definitely hear you about avoiding beating!  We just had an unusually delightful close hauled sail from Bar Harbor to Gloucester, but that is definitely the exception the the rule!  I'd rather wait a week, or sail an extra 1000 miles than spend 3 days beating.

Bill Kinney
SM160, Harmonie
Gloucester, Mass


---In amelyachtowners@..., <svperegrinus@...> wrote :

Bill,

Thanks for the detailed explanation.  My only remaining question is if under "W", the autopilot is trying to optimize VMG to an Apparent Wind Angle AWA of zero, or is it trying to optimize to a shallower angle, say, 10° or 20°.  It seems to me that optimized VMG is not the same to a destination that is {0°, 10°, 20° or 30°} AWA of one's current position.

When under autopilot, we sail in "Wind" mode most of the time by far, so we'll try in the weeks and months ahead to see what we can learn of the VMG algorithm the B&G autopilot uses.  The only problem is that we try and avoid beating like the plague, so it may take a while to accumulate observations on VMG-optimization.

Cheerio,

Peregrinus
SM2K N. 350
at anchor, Thermopylae