Last weekend I participated in a “swimathon” in my town - people swim in the pool for one hour and the one with the longest swim distance wins. The judges count the distance. More of it – they check if people swim correctly, do not change style, swim regularly, and make correct turns. And my Garmin FR255 was counting the distance too. And… there was a difference, so I started studying the case…
This is not my first post here about wrong counting lengths by FR255 – unfortunately adding/subtracting 1-2 lengths on one our swimming is not a big problem for most of us, so there is not a great response. Also, Garmin didn’t make any moves, not any update on the swimming module for… for always as I remember.
The problem is when we start in competitions like I noticed above – everyone's lengths count. I have made an investigation of my swimathon participation data. Garmin has to do very little to fix this. Before, a long time ago, I was using the first Garmin swim watch (2017, monochrome LCD, 2yrs on batt!), which had no problem. Then I was using Garmin Swim 2 and since this model, everything has gone wrong. Garmin stopped developing the swim models line (there is no Garmin Swim 3). And when I am observing FR255 I can see that it has the same behavior and the same bugs as Garmin Swim 2 – they probably do use the same swimming module (algorithm) with no changes. So, I hope there are two points that could help Garmin repair its swimming module:
1. Eliminate adding “free lengths”. Maybe Garmin Connect budges “New record” looks nice to my eyes, but calculating that I swam 50m faster than Michael Phelps could not be true 
As you can see on the table (from Garmin Connect), I used to swim about 40 seconds/length (green frame) and suddenly there are produced two lengths from one (orange frame). There was no stop, no style change, no other illegal moves (no disqualification from the competition 
)
But even if it was me who caused the watch errors with a move unforeseen by Garmin, would none of their developers really see that there is no point in recording that I swam 25 meters in 14 seconds (ok, it could be Michael Phelps) with ONE hit? (marked with arrows) ?! The algorithm should capture something immediately and correct and it doesn't require a million complicated calculations or AI!
2. I have noticed, that wrongly added lengths used to appear after several dozen lengths, never at the beginning of the swimming session. The second notice is, that observing the watch – sometimes it needs a few seconds more to notice that I swam the entire length – there is a little delay before it displays the length (like "hangs"). It was also in the Garmin Swim 1 watch – probably algorithm must count/check/validate the data. This is completely understandable, but in FR255 it probably needs optimization, because everything indicates that these "light suspensions" during measurements cause a “free” length to be added at that moment. Either he calculates something incorrectly, or he is too burdened with calculations and misses something - well in this situation maybe not "misses" but wrongly adds length when it goes back from that "hangs".
I don't know how it is implemented in watches from other manufacturers, but if swimming is still treated as an insignificant addition, swimmers will go ("swim" :-) ) towards new solutions that are starting to appear on the market (a computer-built into the goggles for swimming). It would be a pity, especially since it may only take a little effort to fix it.
Thanks and greetings to all!
