Open water Swim FR945 Settings

How do you know your swims are being measured too long? By how much too long?

Would you post a link to a recent swim or at leasta n image of the track so we can see the gaps? We swim on a 2000m measured course and invariably get distance that are pretty close when you allow for some of the meandering that we do. And yes they usually are on the high side but do also err on the low side. But since they're generally within around 10% I've never been concerned. However, if you are losing the signal in the swim then you might want to talk to Garmin Support. This was an issue early on but has been sorted, at least we're not seeing it this year. What firmware version/GPS version do you have?

Measuring swim open water swim distance feels like a bit of black magic, guesswork, all mixed into any number of pleas and prayers to whatever supreme deity you believe in. That said, Garmin's ability to measure OWS distance has got better, although sometimes there is a backwards step after an update.

As for the settings? Up here in the South we've not found any difference between the satellite configurations whether GPS only or GPS plus one of the others. Might be worth trying another GPS setting to see if you get better results using a different combination. Using Smart or 1s recording s not going to change the distance measured, but might change the look of the track.

Two different 945s - my wife's

And mine on the same course in November

Here are several swims within the past 2 weeks, two using 4.0 and GPS 2.6 and the last one using 3.9. I was able to check the distance using Google Maps. I've had the watch for just a couple of months. I only swim freestyle in open water.

I've played around with Smart recording vs. 1 second, and didn't see much difference.I've also tried using a few different satellite settings and didn't see much difference there either. Which recording method gives the best track? 

The swim below was measured at 3998 yards by the 945. It was closer to 2900 yards.

The swim below was measured at 2632 yards by the 945. It was closer to 1700 yards.

The swim below was measured at 3794 yards by the 945. It was closer to 3000 yards. This one used v3.9 software on the 945.

The best Garmin results were with the 735. The 935 was a step-down from the 735, and the jury is still out on the 945, but I'm not so encouraged - but am VERY hopeful!

While ours do go long on occasion it's never by as much as you appear to be seeing. As bad as some of the swims have been in the past, I've never seen errors that big in the distance. I think you might be best to open a conversation with Garmin Support especially if you are confident that the distance estimated on Google maps is what you'd expect it to be. BTW what's your pace/100yds in the pool? 

Massive ups to swimming in water that cold! At least we're hitting close to 20C!

On a good day, I'm 1:40 in the pool, but can't seem to bring myself to follow the black line given my other option is the 'Big Pool'

These swims were with the current but did require crabbing - we swam 45º into the current, which is the opposite direction from the start to finish line. Crabbing helps not to get swept past the destination.  Water temps are 51F and we swim without wetsuits. 

I already opened a case with Garmin and look forward to their continued and excellent tech support.

Did you get a real answer from Garmin Support?

With Swim2 (but as I see for FR945 it is the same) when there is GPS signal loss, distance is measured via accelerometers, and when GPS is found again, the missing distance between the lost and found GPS signal is ADDED to the already measured distance, what includes the accelerometer only measurement. That means that the distance with lost GPS signal is measured TWICE. This gives you the too long distance.

I reported this to Garmin just today, I hope that they will correct it. This kind of measuring behavior (bug) is totally unacceptable.

Very insightful regarding the accelerometer!   And hopefully, it will assist Garmin in solving this problem.

After a number of interactions and iterations with Garmin tech support, I'm very dissatisfied. While they are responsive, they have told me GPS drift is likely the problem and I don't swim in a very straight line - thus resulting in swims indicated by the device being 25-75% longer than when measured by Google maps post-swim.  They suggest not wearing the watch on the wrist, and I would be better served by putting the watch in my cap or strapping it to my googles. 

I also swim with an Apple Series 4 Watch - which does a much better job on the distance. I've done swims with both watches on the same wrist as well as watches on different wrists. Garmin consistently is inaccurate with their measurements. As another option, Strava can correct the distance post-swim, but then the data is wrong in Garmin Connect.

I hope Garmin will invest in the software resources to solve this problem. Your insights on the accelerometer may just be the missing piece to the puzzle!!! 

Same issue here with FR945. I agree the Apple Watch did a better job with distance. Very frustrating. Garmin, you can do better here. 

Did you get any answer from Garmin? My Fr945 does the same thing. Even if I stop swimming it keeps adding meters. In addition, when I swim against the current the difference is even higher. The last tracking gave me 3147 meters for a real distance of 1600 m. The first half the watch counted 1157 m and when I returned the distance increased in almost 1900m. I think is a shame that a watch with one of the best capabilities wasn't able to provide good measurements in distance.

Garmin responded yesterday indicating they have software coming out 'soon' that will fix the issue. 

I recently completed a long swim where the 945 measured 19 miles for a 13 miles swim. The swim went both with and against the current. Interesting to note, my friend wore a 935, and the distance seemed to be as expected. 

Hi 

I've just purchased a new FR945

My first open swim with it measured double, my usual open water swim is about 1000yrds and it measured 1900 odd and my pace was 20 seconds quicker

It