This is the final report of the problem:

GpsMap 276C Enroute Goto Problem

I am a Garmin user since 1992 and I had more than 10 Garmin gps units;
currently I have in my own boat 3 Gamin's gps (GpsMap130, GpsMap 76
and a GpsMap276C).

Traditionally, in a sailboat we navigate using preplanned routes, but
depending on the weather conditions and other factors, we can skip one
or more waypoints in the route sequence, doing a GOTO to the next
waypoint within the active route; this works well practically in all
Gamin's gps I know and the gps continues changing automatically to
the next waypoint within the route, once it has made the currently
active waypoint.

This is the correct thing to do, as the active route has I high
priority over a GoTo IF the new active waypoint pertains to the Active
Route. Of course, if you do a Goto to a waypoint which does not
pertains to the active route, you are canceling the active route, and
them, when you reach to the waypoint, the gps keeps pointing back to
that waypoint.

In recent software updates, Garmin introduced more options in the
behavior of route waypoint transition, including the manual and
distance algorithms in addition to the traditional automatic way.

Last week we have made a 400 nm trip in a friend's 36 ft sailboat and
have found a problem with the 276C software 3.50, when doing a skip to
a waypoint in the active route, using a Goto as usual. We were
sailing by autopilot but not gps interfaced, from the start of the
trip up to the leg SR05-SR06, because we where on a beating (30-35
degrees of the bow) and making some tackings to keep the boat on the
right side of the route.

After reaching the half of this leg, the wind eased back to a close
reaching point of sailing (45-60 degrees) , and than whe decided to
use the interface of the Autopilot to the gps (276C); to do that, we
had make a GOTO to the waypoint SR06 in the Active Route Page (The
route was already activated since the beginning of the trip) in order
to enter the route exactly at this waypoint, and expecting that the
gps would command the AP automatically to the next wpt (SR07) when the
boat makes the SR06; note that our AP is a Raymarine S1G which have
Gyro aided track, and we where getting a XTE maximum of 10 meters, so
I believe we had made the SR06 very precisely.

This was at night , and when I noticed, the 276C (it is mounted under
the dodger) was pointing back to wpt SR06 (180 degrees of the bow) in
the compass page; I was very surprised, and than go to see what the
other gps (Garmin GpsMap 76CS mounted in the cockpit pedestal, and
loaded with the same routes and having the same route activated) was
showing: he was pointing forward to the next wpt SR07 as expected.

After this, we had put the AP in standby then press Auto, and power
off/power on the 276C expecting it resumed the route pointing to SR07,
but it keeps the GOTO to SR06, so I deactivated the route and activated
it again so that it pointed correctly to SR07; after this, we activated
again the gps interface using the Track bottom on the AP.

This incident make us to pay attention to observe how the next wpts
would be made by the gps and the AP, which was OK, so we concluded
that the problem occurred due the enroute GOTO on the leg SR05-SR06.
At that time, we had think that the gps incorrectly changed the
algorithm of waypoint transition from automatic to manual, even if in
the route setup, the parameter is in AUTO mode.

As anybody with a little sailing experience can understand, this could
a cause a very danger navigation situation, because the Gps keeps
pointing back to the waypoint already made, that is, to back in the
route, which is not the expected behavior. The problem is worst if the
boat has its autopilot interfaced with the gps, as we have with our
Raymarine S1G, since it keeps the boat in the previous track because it
has no other waypoint to go, until we notice the problem, and this
could cause a disaster. In our case, we where lucky because at that
moment, the boat was about 40 nm from the shore.

Trying to replicate the problem, one week later I have made a sail trip
from my marina (AIC) to Itaparica island (ITAP) and back, on my own
36 ft sailboat, using the Garmin GpsMap 276C (Sw 3.50) and I have made
almost all the trip using the Autopilot interfaced with the gps. The
Enroute Goto I have made from wpt USIB to wpt GAT1, skipping the wpt
FBCIM was OK, and the boat was guided as normal to the next wpt on the
route (UI01) after making the wpt GAT1. I do not understand what could
be wrong with my friend's 276C.

But on next day at home, I had powered on my 276C, and put it in
simulation mode, and I had noted that even if my last real position was
near to the end of the route (PITA), the active route (AIC-ITAP) showed
the active wpt as GAT1 (very far in the middle of the route) and when
I put the 276C to navigate in simulation mode and set the speed to 10
knots, it showed in the map page that the boat (simulated) was
navigating from near PITA (correct position of the boat when I had
power off the 276C Saturday) direct to GAT1, which is the enroute Goto
waypoint I had made Saturday about 2 hours before I have reached the
waypoint PITA, having passed two waypoints (UI01 and UI02) down the
route without problem!

Of course, THIS is WRONG and and lead me to think that this could
have caused the error we found in the trip, because the 276C REMEMBERS
the GOTO, if I do a Power OFF/Power ON it resumes the goto, even if I
already have passed the active leg, so it goes back to that goto
waypoint instead of proceeding to the next waypoint of the Active
route.

In fact, our problem occurred when we was navigating the active
route (Iate to Cabanga) and have made an enroute goto to the next wpt
(SR06), but as we had a problem of "No data" with the Gps interface
in the AP, we have made a powerOff/PowerOn on 276C, trying to fix
this, and really, after this, the Autopilot continued receiving the
NMEA messages from 276C again. I know that my friend's boat have
the AP linked by Sea Talk with a Raymarine C80 chart plotter/radar,
and I think that this could be the cause of this intermittent problem
of NMEA messages not reaching eventually the AP.

As this happened some time before the problem, I have concluded that
the problem occurred just because the 276C "remembers" the Goto
when it was Power On again, and even if the actual position of the boat
has passed the SR06, on the active Route, it has erroneously kept the
active goto to SR06.

In my opinion, the 276C must check at power on where it is, and
evaluate the active route again, so that it selects the next waypoint
or next leg of the active route correctly. I found later that my other
gps, Map76 also REMEMBERS the last GOTO, which I still think is wrong
too. But I know that my old GpsMap 130 does NOT remember the GOTO, it
remembers only the active route, and recalculates it correctly. I
think again that this is the CORRECT thing to do.

Of course, this is not the case of a "normal/traditional" goto which,
differently of an "Enroute Goto", is made to a waypoint outside of the
active route, because in this case, the gps should cancel the active
route But even with a normal goto, the unit should power on without
any active goto, which is better than to have a very old active goto
..=2E. or a goto to the wrong wpt.

I have made today another test, to confirm that both the 276C and the
Map76 have the same behavior that is, they "remember" the last "enroute
Goto" but they do not remember a normal Goto (wpt outside the active
route) after a power off/power on.

And a test with my old but very good Gpsmap130 confirmed that it DO
NOT remember anything, nor the enroute goto, nor the normal Goto; it
remembers only the active route, after a power off/power on, and
recalculates it normally, which I think is the correct thing the gps
must do. After a normal Goto, it deactivates the route and powers on
correctly without any active route or any active goto.

Concluding, I think that 276C is working the wrong way after a power
off/power on, because it resumes the old enroute goto even if the
position now is very far from the position when the enroute goto was
made, and it do not recalculate correctly the next wpt/leg that should
be active after the power on. Remember that, the unit could be
powered on, many hours' or even days after it was powered off and it
can be at dozens of miles away....

So I am asking that the Garmin team responsible for the marine units'
software, analyze carefully this incident and that Garmin corrects the
GpsMap 276C software/firmware as soon as possible, as it creates a
great impact in the marine navigation function of this unit. And off
course, after Garmin corrects the software of 276C, I think Garmin
should correct the software of Map76 too, and eventually the software
of others models of marine gps.


Pascal Gon=E7alves

Could you possibly restate the problem with more detail?

Thanks,

You've made some good arguments for a particular protocol to be followed
regarding enroute GoTo's, using logic that makes sense based on the
situation you were in. It seems to me that one could also argue logically
to the contrary, i.e., the enroute GoTo should be keep active under all
conditions including after a power interruption (which may or may not have
been observed), until the Active Route is cancelled. Setting an enroute
GoTo, in a general sense, could be viewed in the context of an emergency
manuever. Seeing it as necessitated by a dangerous condition, it becomes
paramount that the waypoint be made good -- and if that means turning back
180 degs., so be it.

I would suggest that because you were very observant and well aware of what
you were doing and what you wanted to happen, you had expected the same of
the GPS. Too much to ask IMHO -- so the GPS errs on the side of caution in
sticking hard on that enroute GoTo waypoint.

My two cents FWIW.

Len
--
Eliminate "ns" for email address.
"Pascal" wrote in message
oups.com...
This is the final report of the problem:

GpsMap 276C Enroute Goto Problem

I am a Garmin user since 1992 and I had more than 10 Garmin gps units;
currently I have in my own boat 3 Gamin's gps (GpsMap130, GpsMap 76
and a GpsMap276C).

Traditionally, in a sailboat we navigate using preplanned routes, but
depending on the weather conditions and other factors, we can skip one
or more waypoints in the route sequence, doing a GOTO to the next
waypoint within the active route; this works well practically in all
Gamin's gps I know and the gps continues changing automatically to
the next waypoint within the route, once it has made the currently
active waypoint.

This is the correct thing to do, as the active route has I high
priority over a GoTo IF the new active waypoint pertains to the Active
Route. Of course, if you do a Goto to a waypoint which does not
pertains to the active route, you are canceling the active route, and
them, when you reach to the waypoint, the gps keeps pointing back to
that waypoint.

In recent software updates, Garmin introduced more options in the
behavior of route waypoint transition, including the manual and
distance algorithms in addition to the traditional automatic way.

Last week we have made a 400 nm trip in a friend's 36 ft sailboat and
have found a problem with the 276C software 3.50, when doing a skip to
a waypoint in the active route, using a Goto as usual. We were
sailing by autopilot but not gps interfaced, from the start of the
trip up to the leg SR05-SR06, because we where on a beating (30-35
degrees of the bow) and making some tackings to keep the boat on the
right side of the route.

After reaching the half of this leg, the wind eased back to a close
reaching point of sailing (45-60 degrees) , and than whe decided to
use the interface of the Autopilot to the gps (276C); to do that, we
had make a GOTO to the waypoint SR06 in the Active Route Page (The
route was already activated since the beginning of the trip) in order
to enter the route exactly at this waypoint, and expecting that the
gps would command the AP automatically to the next wpt (SR07) when the
boat makes the SR06; note that our AP is a Raymarine S1G which have
Gyro aided track, and we where getting a XTE maximum of 10 meters, so
I believe we had made the SR06 very precisely.

This was at night , and when I noticed, the 276C (it is mounted under
the dodger) was pointing back to wpt SR06 (180 degrees of the bow) in
the compass page; I was very surprised, and than go to see what the
other gps (Garmin GpsMap 76CS mounted in the cockpit pedestal, and
loaded with the same routes and having the same route activated) was
showing: he was pointing forward to the next wpt SR07 as expected.

After this, we had put the AP in standby then press Auto, and power
off/power on the 276C expecting it resumed the route pointing to SR07,
but it keeps the GOTO to SR06, so I deactivated the route and activated
it again so that it pointed correctly to SR07; after this, we activated
again the gps interface using the Track bottom on the AP.

This incident make us to pay attention to observe how the next wpts
would be made by the gps and the AP, which was OK, so we concluded
that the problem occurred due the enroute GOTO on the leg SR05-SR06.
At that time, we had think that the gps incorrectly changed the
algorithm of waypoint transition from automatic to manual, even if in
the route setup, the parameter is in AUTO mode.

As anybody with a little sailing experience can understand, this could
a cause a very danger navigation situation, because the Gps keeps
pointing back to the waypoint already made, that is, to back in the
route, which is not the expected behavior. The problem is worst if the
boat has its autopilot interfaced with the gps, as we have with our
Raymarine S1G, since it keeps the boat in the previous track because it
has no other waypoint to go, until we notice the problem, and this
could cause a disaster. In our case, we where lucky because at that
moment, the boat was about 40 nm from the shore.

Trying to replicate the problem, one week later I have made a sail trip
from my marina (AIC) to Itaparica island (ITAP) and back, on my own
36 ft sailboat, using the Garmin GpsMap 276C (Sw 3.50) and I have made
almost all the trip using the Autopilot interfaced with the gps. The
Enroute Goto I have made from wpt USIB to wpt GAT1, skipping the wpt
FBCIM was OK, and the boat was guided as normal to the next wpt on the
route (UI01) after making the wpt GAT1. I do not understand what could
be wrong with my friend's 276C.

But on next day at home, I had powered on my 276C, and put it in
simulation mode, and I had noted that even if my last real position was
near to the end of the route (PITA), the active route (AIC-ITAP) showed
the active wpt as GAT1 (very far in the middle of the route) and when
I put the 276C to navigate in simulation mode and set the speed to 10
knots, it showed in the map page that the boat (simulated) was
navigating from near PITA (correct position of the boat when I had
power off the 276C Saturday) direct to GAT1, which is the enroute Goto
waypoint I had made Saturday about 2 hours before I have reached the
waypoint PITA, having passed two waypoints (UI01 and UI02) down the
route without problem!

Of course, THIS is WRONG and and lead me to think that this could
have caused the error we found in the trip, because the 276C REMEMBERS
the GOTO, if I do a Power OFF/Power ON it resumes the goto, even if I
already have passed the active leg, so it goes back to that goto
waypoint instead of proceeding to the next waypoint of the Active
route.

In fact, our problem occurred when we was navigating the active
route (Iate to Cabanga) and have made an enroute goto to the next wpt
(SR06), but as we had a problem of "No data" with the Gps interface
in the AP, we have made a powerOff/PowerOn on 276C, trying to fix
this, and really, after this, the Autopilot continued receiving the
NMEA messages from 276C again. I know that my friend's boat have
the AP linked by Sea Talk with a Raymarine C80 chart plotter/radar,
and I think that this could be the cause of this intermittent problem
of NMEA messages not reaching eventually the AP.

As this happened some time before the problem, I have concluded that
the problem occurred just because the 276C "remembers" the Goto
when it was Power On again, and even if the actual position of the boat
has passed the SR06, on the active Route, it has erroneously kept the
active goto to SR06.

In my opinion, the 276C must check at power on where it is, and
evaluate the active route again, so that it selects the next waypoint
or next leg of the active route correctly. I found later that my other
gps, Map76 also REMEMBERS the last GOTO, which I still think is wrong
too. But I know that my old GpsMap 130 does NOT remember the GOTO, it
remembers only the active route, and recalculates it correctly. I
think again that this is the CORRECT thing to do.

Of course, this is not the case of a "normal/traditional" goto which,
differently of an "Enroute Goto", is made to a waypoint outside of the
active route, because in this case, the gps should cancel the active
route But even with a normal goto, the unit should power on without
any active goto, which is better than to have a very old active goto
.... or a goto to the wrong wpt.

I have made today another test, to confirm that both the 276C and the
Map76 have the same behavior that is, they "remember" the last "enroute
Goto" but they do not remember a normal Goto (wpt outside the active
route) after a power off/power on.

And a test with my old but very good Gpsmap130 confirmed that it DO
NOT remember anything, nor the enroute goto, nor the normal Goto; it
remembers only the active route, after a power off/power on, and
recalculates it normally, which I think is the correct thing the gps
must do. After a normal Goto, it deactivates the route and powers on
correctly without any active route or any active goto.

Concluding, I think that 276C is working the wrong way after a power
off/power on, because it resumes the old enroute goto even if the
position now is very far from the position when the enroute goto was
made, and it do not recalculate correctly the next wpt/leg that should
be active after the power on. Remember that, the unit could be
powered on, many hours' or even days after it was powered off and it
can be at dozens of miles away....

So I am asking that the Garmin team responsible for the marine units'
software, analyze carefully this incident and that Garmin corrects the
GpsMap 276C software/firmware as soon as possible, as it creates a
great impact in the marine navigation function of this unit. And off
course, after Garmin corrects the software of 276C, I think Garmin
should correct the software of Map76 too, and eventually the software
of others models of marine gps.


Pascal Gonçalves