Open Water Swim Question.

In my experience ( fs6)swimming breaststroke the watch is most of the time submerged and doesn’t catch the signal and the results are odds 

swimming free style it works fine

I am curious to try my fsss7

Swam in the huge pool in Mexico (at a resort) again yesterday.  Swam for 30 minutes at my normal very steady pace.  Used open water instead of pool swim.  No lengths set, just pure GPS.  Clear day.  Very bright sun.  Strong GPS signal.  The track recorded well on the map when you replay it.  The watch recorded 640 yards when I know for sure it was at least 1000 meters because I know my pace from daily 1000 meter swims in an Olympic pool,  

This is not a big concern for me because I know my pace and don't need GPS on a pool swim.  I'm just reporting what happened.  I guess on a long straight open water swim the watch would perform better.  But why?  

My stroke was freestyle, so the hand is under water more than half the time.  I saw on a 3-year-old thread about this that it is best to set GPS at 1 second, but I'm assuming when one chooses the open water app that the app optimizes GPS for swim.  Are there any settings that i could be messing up here?  

It's an old bug : Fenix 6s Open Water Swimming under reporting distance & pace - fēnix 6 series - Wearables - Garmin Forums , it happening the same for me. I cant' use Garmin watches for my open water swim activities. Solution, for me, is to use a Suunto 9 peak. If you want to do a test, just upload your activity to Strava and use "distance correction", magically it will appear correct distance. I also did a quick test : Delta Solar open water swimming bug - YouTube . As you can see for the same distance with 2 different activity, watch reports 2 different distances. I'm tired to report this bug to beta team, after so many years, i just live with it and use a different watch for open water swim.

@philipshambrook will reply that's it's all ok for him in 3, 2, 1....  

Thanks.  That seems strange since triathletes and open water swimmers would be in full riot absolute revolt if Garmin Fenix watches were never accurate on distance with the open water swim app.  But on my two swims it reports around 600 yards when I know it was over 1000 meters.  That means for those two swims the distance was nonsensical and useless, yet the recorded track was perfect.  I'm about to go try it again because I'm about to swim a 1000 in that huge and awesome pool.  

My big challenge is as I swim by the very long pool bar, not to stop and swig a margarita!  

gregjohnson1956 said:

That seems strange since triathletes and open water swimmers would be in full riot absolute revolt if Garmin Fenix watches were never accurate on distance with the open water swim app.

Exactly.

I suspect your distance issues might be related to the closed circuit nature of the pool. There is no doubt that OWS distance accuracy is affected by short circuits, which is understandable given how the algorithm works; basically best guess using a combination of very intermittent GPS fixes and accelerometers to determine direction and distance. Clearly, long straight swims are more likely to result in better accuracy.

As for Strava's adjusted (who's to say it's any more correct than Garmin?) swim distance making a significant difference - this from a swim this morning https://www.strava.com/activities/6762772585. Strava also adjusted the moving time.

Unadjusted:

Adjusted:

Strava only corroborates a fixed measured distance taken from google maps, car tachymeter,  strava, other watches and fixed buoys. Ah all these tools are wrong , Garmin is the ony truth! Ave Garmin! LOL! @gregjohnson1956, who's to say that pool is 1000m? If Garmin measured 640y, the pool swim length is clearly wrong! LOL! 

Renton, you didn't read my post.  There was no swim length entered.  I used the open water app, not the pool swim app on these 3 swims.  It is a huge resort pool shaped in a randomly curved pattern.  There are no lanes.  I swam around the periphery and some back and forth  Today (the third swim) I swam 31 minutes and it recorded 680 yards.  Swimming 31 minutes at the pace I was swimming today is 1100 meters at least.  Probably more.  Today, I even changed the data to 1 second, but it still recorded the swim way too short.

Garmin can pipe in, but I think it is simply that the GPS does not record the distance accurately for short little circular routes like that.  It needs longer legs.  That is what one poster here said.  I don't need GPS in a pool swim.  I was just experimenting and thought it was interesting that the open water app and GPS is grossly underreporting distance when swimming in a very big pool. 

Anyway, today I know absolutely for sure I swam at least 1100 meters and it reported 680 yards.  That's 3 days in a row that an 1100 meter swim was reported as about 680 yards.  How do I know I swam 1100 yards?  Because I swim 1000 meters 6 days a week in a 25 meter or Olympic 50 meter pool for exercise, and I know my pace very well.    

I have not used the watch for an open water swim in the ocean with long legs.  I bet it would work fine in that case, which is what it is intended for.  Swimming circles in a huge pool?  It doesn't report distance at all correctly.  Not even close.  

OK, I will try this.  When I get back home I will use the open water app instead of the pool swim app to record a 1000 meter swim in an Olympic 50 meter pool.  I will swim 1000 meters, which is 20 lengths.  We''ll see if the watch records 1000 meters on a freestyle stroke.  I don't think the watch is intended for that.  Is the GPS good enough to pull that off?  20 50 meter lengths using GPS (not entered pool lengths).  That outdoor 50 meter pool is heated because the Navy trains in it.  

gregjohnson1956 said:

Is the GPS good enough to pull that off?  20 50 meter lengths using GPS (not entered pool lengths). 

This hasn't been done with the F7/Epix that I am aware of but pretty sure the answer will be no, the GPS is not good enough to be used in an outdoor lane pool.

I haven't swum in a pool with my F7 yet but there have been reports of problems using the Pool Swim app. Hopefully that will be fixed before I have to go back swimming in a pool.

renton82 said:

Strava only corroborates a fixed measured distance taken from google maps, car tachymeter,  strava, other watches and fixed buoys.

I don't think it does. My understanding is that it makes adjustments to the fit file received from Garmin, calculating the results differently. Hence why not only distance changes but time too.

Apologies if the reply was meant to be taken as a joke.

This from Strava - support.strava.com/.../216919487-How-Distance-is-Calculated