Open Water Swim - Map not showing up?

Look I have very very little experience with FR945, with sport watches in general and alos with OW swimming. So take my answer with a grain of salt. I do own a FR945 and I started to do ow swimming sessions around a month ago. The first times I think I had the same problem as you re having right now. The watch was telling me how many meters I was swimming and the number was very reasonable but i got no map

The question is: did you get the GPS signal before starting the session. Ie, did you wait until the red bar becomes green? I actually have to wait a lot!! Like 5 minutes at least, I dont know if that is normal.

I am under the impression that if you do not wait, the watch will not use GPS and will just try to estimate how long you swam.

Hopefully someone more knowledgable than me will shed more light...

You got no GPS signal, distance was measured from accelerometers, Garmin guesses distance from stroke rate.

First make sure that GPS is on, have a strong GPS signal, have 1-2 minutes of GPS soak, have current CPE file. Then make sure that you use proper swim technique with arms periodically coming over the surface - front crawl or backstroke, but definitely avoid breaststroke!

If all that do not help, switch the watch to the other arm - no kidding here, even with symmetrical stroke technique the watch might hold good GPS signal on one arm but bad on the other.

Since we are here, let me avoid opening another thread and ask you: is it normal that I take like 5 minutes to get the GPS signal? When I (for example) bike, it takes around 10 seconds I would say...

No, it is not normal, usually getting the GPS signal takes about 10-15 sec. Actually it does not matter if it is running, biking, swimming or any other type of activity. I would guess that you have an expired CPE file (check "about" on the watch).

https://support.garmin.com/en-US/?faq=388HjIB8mK2OPz6vycgPb6&partNumber=010-02063-00&searchQuery=How%20is%20GPS%20Location%20Data%20Downloaded%3F&tab=topics

https://support.garmin.com/en-US/?faq=ZCFBNlxeiM3oipPmFoYfs7&partNumber=010-02063-00&searchQuery=How%20is%20GPS%20Location%20Data%20Downloaded%3F&tab=topics

Also if you look back in this forum, you will find several topics about this

Humm... if i go to About and scroll down i see CPE: Current.

But this is as of now....

When I was taking those open water swims, i was on holiday.... at least 1000 km from here...... During my holday I never synced my watch: I had no laptop with me and i do not have a smartphone....

Maybe that's the reason... But also according to garmin support, i dont see a solution for a situation like mine, where you travel to another place and you dont have pc/phone...

Also, the accuracy of the gps was quite horrible in one of the sessions... can this be related or it is like a black and white thing (ie you might need a long time to get the signal, but once you get it, it should be ok)?

In case you don't have smartphone or laptop to sync with, and CPE is expired, you can get current CPE by letting the watch untouched outside with GPS set on for about 15-20 minutes. This usually needs an activity recording, as with just getting the GPS signal without recording, the watch will time out and quit from GPS mode for saving battery. And also you need a safe place for the watch not to get stolen.

For OW swim in my experience if GPS signal is acquired, that should be enough to hold a strong signal, if CPE is current. But in one thread someone said that even with expired CPE the track was correct. So I guess that CPE is needed for finding the signal only, and if the swim style is good enough to keep the signal, CPE is not needed any more.

For me, if I wear the watch on the left arm, no matter what I do, the GPS signal is always lost, and the track is horrible. WIth the watch on the right arm, I do not have problems. (note that I use Swim2, but I experienced the same with FR945 during a test swim)

Thanks a lot for helping!! This is very relevant to me since most of my ow swims happen after a fairly long trip.

First of all, is it correct to say that if I see "CPE: Current" just before the swim, then I am free to go and I should experience no problems with GPS?

If so, assuming that I do not see "CPE:Current", would it work if i try to connect to a wifi say in a hotel/restaurant/cafe adn then do a wifi sync? Would that be enough?

Otherwise your other soultion: the watch must be untouched and unmoved? So if I go for a short walk/run it would not do the trick, would it?

"is it correct to say that if I see "CPE: Current" just before the swim, then I am free to go and I should experience no problems with GPS?"

That's why I brought my example with the watch on different arms. So ideally there should be no problem, but for me there is always problem if watch is worn on the wrong arm, regardless of the GPS signal strength. Don't ask me why, I do not consider my swim stroke asymmetrical, but I do not see myself from outside either.

I can not comment on wifi connection, my Swim2 does not have it.

For GPS soak the best way is to leave it untouched. GPS data flow from the satellites are very slow, and every move disturbs the connection a bit.

this story of right/left arm you re mentioning is very odd!! On how many sessions are you basing your conclusions? Are you sure it s not a coincidence?

I should do a couple of 1h sessions this weekend.. I ll let you know.

In any case, from what you said and reported, it looks like that if CPE is not current, i ll also have a hard time with for example running activities. So I ll do the following: I ll check CPE the morning before the swim and (if i see cpe current) i ll try to do a quick test run. If also run is fine, we ll see what happens with the swim...

Actually - forgot to mention before - also very high cliffs (about 20/30m) might disturb the watch if you re swimming close to the coast (about 50m). Can that be?

I made 41 OW swim activities since middle of April, about 10 of them were just short test swims. In the beginning I used only left arm (I normally wear any watch on the left), and I had 100% failure, always right at the first stroke. During the troubleshooting process once I switched to the right. And miracle happened, my watch started to work, and recorded a perfect track (during that switch I had a FR945 on the left arm, what failed completely). Since then if I switch to the left (only short tests), always wrong, when on the right, always perfect. Earlier I had a FR910XT on my other arm for backup, now I record only with Swim2 (again, same OW swim software for both Swim2 and FR945). I did not want to accept this thing, but my watch was stronger... I can reproduce the issue at any time. After a long swim with perfect track watch on the right, I switch my watch to the left, start a new activity (and do not change anything), swim the same style front crawl for a while, and the track is a mess. (FR910XT can measure the track with the same quality on both arms) - yes, I agree, it is totally weird and unbelievable          

I think it is worth to make a test in case your OW tracks have much GPS loss. If not, don't touch anything.

High cliffs might hide some of the satellites making the tracking more difficult.