Can I use my Garmin Forerunner 55 for Open Water Swimming?

See post from tmk2 -

tmk2 said:

Indeed, the Forerunner 55 does not have a dedicated open water swimming mode. If you want fairly accurate distance tracking for open water swims, you would have to keep the watch under your swimming cap, so it has unrestricted access to GPS signal.

Thank you for the tip. I don’t wear a hat when swimming so what other option could I do? If I set the watch for a pool swim , would this give an accurate reading?? 

Barry H said:

what other option could I do?

There is no other option.

Barry H said:

If I set the watch for a pool swim , would this give an accurate reading?? 

No.

Hi,

why not using the Other or Cardio Option and just go ahead. GPS will track your distance. What is missing?

GPS won't be accurate and even nonexistent if your watch is underwater much of the time.

and an open water device app would be better for that? Just curious what other devices like 745 and 945 offer differently. thx

rentagreement said:

and an open water device app would be better for that?

Yes.

rentagreement said:

Just curious what other devices like 745 and 945 offer differently.

They have special algorithms for compensating for impaired GPS reception in open water swimming scenarios.

Not trying to be difficult or a smartypants here but I have to ask, why would reception be necessarily impaired? Running around a forest, or a track in a city, would seem to me to be harder for maintaining satellite reception than swimming outside for example in a lake, inherently well open to the sky. Or is it the motion of the swimmder that is the problem? I just don't get why if you are swimming up and down the sea by a 400 m beach that you can't just fool the watch by telling it ir's a very large pool.

Dizzy said:

why would reception be necessarily impaired?

Because the watch spends most of the time submerged in water, and water absorbs perfectly the radio waves that GPS utilises.

Dizzy said:

I just don't get why if you are swimming up and down the sea by a 400 m beach that you can't just fool the watch by telling it ir's a very large pool.

You could, but there are two problems:

1. You would need to use the pool swimming profile, and that keeps GPS off, which means you won't get a map of where you swam.

2. There is a limit on pool size in the pool swim mode. I don't remember the limit now, but 400 m certainly exceeds it.

Great thanks, those are good points - I'd forgotten GPS gets switched off for pools DOH
As I was walking out today it did dawn on me that with arm strokes you're likely to have the watch in and out of water too fast for GPS to get a fix. It's going to be good to have a watch that will at least remind me I need to get out of the water after a set time.