Open water distance issues

For soak he is only asking for 2 to 3 minutes.  I have not started the activity until I was already in the water and as soon as the green bar was good, off I went.  As you do is what I plan to do next time.  Start the activity while still on land, getting ready, etc.  By the time I get in the water and start I will shoot to give it 5 to 10 minutes of soak and give it a try.  I have seen some similar drift with the prior watches F5 and F3 but it was always minor and I think in those cases it actually re-adjusted itself to be as correct as possible.  In other words what I envision is they have a good signal when I start, then they lose signal as I swim but if I take a rest and my hand is out of water long enough they get a second good gps point (worse case) and connect the dots and do their best to come up with distance.  So the drift I saw with past watches eventually gave me a total distance that was "close enough" .  With the 6x it is different.  While I swim (supposedly bad GPS signal) I feel that the distance is close enough.  I say "feel" because I can only approximate that my 500 yards vibration alert came in at around the right time.  So I think they are doing a good job connecting what samples they get to, on the fly while I swim to calculate distance.  But then when I stop, they over compensate and somehow really mess up the total distance which was fine enough prior to the "rest/pause" correction.  Long story is that I never, ever with prior watches, on all my open water swims, ever, came up with close to double the distance actually swam, ie swim 1 mile but have garmin show 2 miles with a perfect track.  So I hope it is something that eventually can be fixed otherwise the F6 is useless to me for open water. 

In fairness I've not swam open water with 10.10 as it's a bit too cold getting out of the water now so it is possible that there has been a change. This has happened in the past and rectified after the next update.

There are people swimming open water who have not had issues prior to 10.10 and are swimming open water who might be able to verify whether or not there is a change.

1. I did an OWS today using F6x pro and a Suunto 9baro. I checked the distance by Google maps to about 1460 m.  Here‘s what the Suunto measures:
2. and here‘s what the F6 measures:
3. when looking at details, it seem that F6 is adding ghost distance from 1000 m onwards: 
4. this is really annoying and have to be fixed soon.

Interesting, if you look at the tracks mine is a straight line (indicating no gps signal therefore a straight line) but yours seems more realistic (indicating gps signal was adequate) but yet the distance is still off. That may indicate that my watch may have a gps issue at the corner case of open water but that garmin sw can still use some improvement. i have a new watch coming in today and will do another open swim this weekend, we shall see. 

Yesteday I swam with my watch and I noticed one thing - after 500 meters I stopped for a moment to rest. When I continued my watch added 300 meters in just 3-4 seconds. I know that because I set my alerts in the watch to every 100 meters
Why is that?
Perhaps I should press stop when I was resting and then start watch again....?
No idea..

That is exactly what I am seeing. I just got the new watch and its the same issue.  So I dont think its the watch.  The point is that while we supposedly have a less than desired GPS signal (straight line) the distance and track is correct.  Verified by the vibrate alert I get every 500 yards which is in line with the distance, and the track is verified by viewing it.  It is only while stopping, it gets a good fix on the SAT and corrects again, but this time it throws the total distance off.  This is why I believe if I (we) swam without stopping at all we would have good distance.  It may be why others who don't stop long enough to get that better SAT fix do not see an issue.  Anyone who is reading this and doesn't mind a test, go swim normally, then stop with your watch hand out of water to get a good GPS fix (without pressing STOP) and stay like that for a few minutes. My bet is that everyone (or some or most) will observe the same issue we are seeing.

Today, I observed this while stopping. Prior to stopping the distance was close enough to accurate.  I stopped and within a few seconds I saw the distance jump 100 yards, then another yards, etc, for a total of about 500 yards while I was not moving.  It is these jumps that cause the distance being way off and too long.  

My theory is that the watch with sub-par GPS in open water is somehow connecting the dots and doing just fine with distance.  But, as soon as the SAT signal improves in the middle of the swim (pause with hand out) it over compensates distance, but track still looks good.  I think its all in their algorithm doing a good job while swimming but messing up if the signal drastically improves in the middle of the swim.

And when you Press stop while resting the same happens?

Have you tried it?  

No I haven't but what I want to try is

1. Swim without stopping.

2. If I stop, keep my hand in the water to prevent a good SAT GPS fix. 

(I think that's whats throwing off the distance, the mid-swim drastically improved GPS signal and somehow the watch adds much distance, seemingly without affecting the track)

The same story today.
I tried to press stop but anyway it added some distance (100 meters - I swam with strava in my bouy)
Next time I will try to keep my hand in water as you suggested

If your distance was just 100 meters longer its not as bad as what I am seeing. If I just had 100m off I wouldn't mind at all. My last swim was about 1K and the GPS recorded 1.7K