Open water swimming

LadysmithBOB
LadysmithBOB Registered Users Posts: 1
New Traveler
edited January 24 in TomTom Sports
I want to use GPS sport watch when swimming in the ocean
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  • tfarabaugh
    tfarabaugh Posts: 16,939
    Superuser
    I want to use GPS sport watch when swimming in the ocean

    It can't be done easily as the watch does not support open water swimming using GPS, it is for pools only. Calculating GPS while swimming is much more complicated than counting strokes and figuring out the stroke length. It cannot detect GPS underwater so it would need to time the GPS signal attainment with the split second the watch is above water on each stroke (assuming you are doing a stroke that brings your arms out of the water). This is a very difficult thing to compensate for and it has been a mixed bag on all devices, none of them do it perfectly well and many have not even tried, like TT. What most users who want open water swimming do is to use freestyle mode and put the watch in their cap or on a safety buoy behind them so it stays out of the water. You will then get distance but will lose swim specific metrics, however.

    I hope this helps, please let me know if this answered your question. If it did, please mark it as a solution so others can look for it if they have the same question.
  • DALawson
    DALawson Registered Users Posts: 4
    Master Traveler
    Excellent suggestion to use Run mode in other forum
  • andy2015
    andy2015 Registered Users Posts: 12
    Legendary Explorer
    Has anyone had any luck with open water swimming?

    I understand the issue with GPS, but even jagged lines would be ok, as I usually (try to) swim in a straight line.

    I understand that HRM isn't designed to work in the water - just wondering if anyone has tried (maybe with the watch a little tighter?)

    My lake swimming season is about to start, I will update you with my findings.
  • Chas1203
    Chas1203 Registered Users Posts: 26
    Outstanding Explorer
    forgetting about GPS, couldn't it still calculate the metrics? Garmin offer this.
    tfarabaugh wrote:
    I want to use GPS sport watch when swimming in the ocean

    It can't be done easily as the watch does not support open water swimming using GPS, it is for pools only. Calculating GPS while swimming is much more complicated than counting strokes and figuring out the stroke length. It cannot detect GPS underwater so it would need to time the GPS signal attainment with the split second the watch is above water on each stroke (assuming you are doing a stroke that brings your arms out of the water). This is a very difficult thing to compensate for and it has been a mixed bag on all devices, none of them do it perfectly well and many have not even tried, like TT. What most users who want open water swimming do is to use freestyle mode and put the watch in their cap or on a safety buoy behind them so it stays out of the water. You will then get distance but will lose swim specific metrics, however.

    I hope this helps, please let me know if this answered your question. If it did, please mark it as a solution so others can look for it if they have the same question.
  • tfarabaugh
    tfarabaugh Posts: 16,939
    Superuser
    Chas1203 wrote:
    forgetting about GPS, couldn't it still calculate the metrics? Garmin offer this.
    tfarabaugh wrote:
    I want to use GPS sport watch when swimming in the ocean

    It can't be done easily as the watch does not support open water swimming using GPS, it is for pools only. Calculating GPS while swimming is much more complicated than counting strokes and figuring out the stroke length. It cannot detect GPS underwater so it would need to time the GPS signal attainment with the split second the watch is above water on each stroke (assuming you are doing a stroke that brings your arms out of the water). This is a very difficult thing to compensate for and it has been a mixed bag on all devices, none of them do it perfectly well and many have not even tried, like TT. What most users who want open water swimming do is to use freestyle mode and put the watch in their cap or on a safety buoy behind them so it stays out of the water. You will then get distance but will lose swim specific metrics, however.

    I hope this helps, please let me know if this answered your question. If it did, please mark it as a solution so others can look for it if they have the same question.

    If you put it in swim mode you can get stroke count but that is about it. You won't get laps as you are not turning and you won't get distance as you can't set a pool size (distance is laps x pool size).
  • DALawson
    DALawson Registered Users Posts: 4
    Master Traveler
    As mentioned in a comment I made recently, in a different forum I read that Run mode works very well - although I haven't been near open water yet to validate.

    But I've pretty much given up on using the watch in swim mode as it doesn't count laps properly unless you touch the wall with you hand and wait for it to register! Maybe a nice gimmick if you could 'resort breaststroke' laps to get to the in-pool bar and back to your lounge chair.
  • Sleen
    Sleen Registered Users Posts: 1
    Apprentice Traveler
    tfarabaugh wrote:
    If you put it in swim mode you can get stroke count but that is about it. You won't get laps as you are not turning and you won't get distance as you can't set a pool size (distance is laps x pool size).

    I'd imagine if you set the pool distance to say 1000m and you swim in open water for that distance, you'd get stroke and distance count?
  • tfarabaugh
    tfarabaugh Posts: 16,939
    Superuser
    Sleen wrote:
    tfarabaugh wrote:
    If you put it in swim mode you can get stroke count but that is about it. You won't get laps as you are not turning and you won't get distance as you can't set a pool size (distance is laps x pool size).
    I'd imagine if you set the pool distance to say 1000m and you swim in open water for that distance, you'd get stroke and distance count?
    No you would not as you are not performing turns so it is not going to count laps and therefore not count distance, It does not base distance on stroke count as it has no way of knowing the distance you cover in a single stroke.
  • engant
    engant Registered Users Posts: 3
    Apprentice Traveler
    i tried with a pool size of 300m but i would that this is not very safe. I thing swim mode is for pool(i haven't try it yet). I havent try the run mode, i m curious of using it. Another trick i made is uploading a trail by google maps, in the sea and approximately near the swimming area and a get a result of distance, heart rate, calories(through the GPS counter) in the watch and in the Tom Tom software
  • elinormoon
    elinormoon Registered Users Posts: 10
    Master Traveler
    edited August 2019
    I used Freestyle mode for swimming and then changed it in Strava to a swim - worked really well! GPS does drop out if you keep your arm under water but quickly comes back when your hand is out. Also, HR seemed to work OK, not sure how accurate it is but was about what I expected.