Open water distance issues

Nice to be heading towards summer in my part of the world so starting to get back in the sea again. Chilly 13C water but bright sunshine for the standard 2km swim down the buoy line and back. F6 Pro and Marq on 11.76b and whatever the latest GPS version is. As you can see the F6 returned the usual track but the Marq was a bit awry (yes I have sent the data to the Marq beta team)...Stopped at the first buoy on the way out and on the way back, and also at the end of the line with watches held clear of the water checking for extra distance accrual, of which there was none.

Looking at your track and not seeing the straight lines means your watch had good GPS signal throughout your swim.  When you look at my tracks, often you see a straight line which implies no GPS signal and dead reckoning is used.  So, why are you and many others get reasonable GPS signal and me and other do not?  It is either swim style of GPS issues with my watch.  Since they sent me a different watch which behaved the same way I somehow dont think is HW related.  So for me, the new GPS chipset and not working well with my swim style.  I say the new GPS chipset because I did not have these swim issues with prior Garmin watches.  So I do know that my SPM is slow, mid 20s or so.  Does that mean I spend too much time with my hand under water, maybe, I dont know.  Not OW swimming these days, (fall/winter coming) so hopefully by next spring/summer they'll have it sorted or I will just wait the F7

What I fail to understand is why, even though the watch sometimes gets a good GPS signal throughout the swim, does it then overestimate the distance by a very large amount. They do advise not to use breaststroke, so I compensate for that by deliberately putting my wrist out of water as much as possible. I agree that this season's swimming days may be over. I'm still awaiting a satisfactory response from the help desk. They take up to a week or more to answer. 

avikoren1 said:

Looking at your track and not seeing the straight lines means your watch had good GPS signal throughout your swim.

and that would also explain why I see little distance added when I stop.

avikoren1 said:

So I do know that my SPM is slow, mid 20s or so.  Does that mean I spend too much time with my hand under water, maybe, I dont know. 

That's a very real possibility as my stroke rate is around 30. Saying that, the Marq has always had issues with the open water swim. I only posted it here for comparison as obviously I was swimming with both arms at the same speed on the same course.

avikoren1 said:

So for me, the new GPS chipset and not working well with my swim style.  I say the new GPS chipset because I did not have these swim issues with prior Garmin watches.

That is indeed unfortunate as I've no had any major issues with any of the Garmin watches when swimming in the sea over the years. I do have some pretty tragic results when the 910/920/935/945 first came out (I collect watches lol!..then fob them off to my wife much to her disgust) but generally Garmin have sorted the issues out pretty quickly.Took a while with the 5+ and still struggling to get consistent results from the Marq.

Because it really has no idea where you've been. To be honest you are on the losing side expecting to get reasonable results when swimming breaststroke. You'd be better off spending the winter months in the pool learning freestyle.

Another swim comparing 945 and F6 this morning with very little difference between the two. Even had some company...