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  #1  
Old 09-13-2014
Talvi Talvi is offline
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Default Calculating OW from pool distances

I'm thinking of doing a sea channel swim (the Bosphorous). How would you advise to calculate open water capability from pool capability?

Obviously the OW conditions, waves temp etc, are a factor, but ignoring this for the sake of simplicity, I'm wondering how continuous swimming compares with pool swimming in your experience? How far in the pool "feels" like for instance 1500m in OW?

I'm just after a rough and ready riule of thumb rather than rocket science
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  #2  
Old 09-14-2014
Caro Caro is offline
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In my experience if there is no current times will be very similar (whether wearing a wet-suit or not), within a minute or two of pool times. Most people are faster if wearing a wet-suit - even buoyant people with good balance. Wet-suits hold you in and make you more streamlined and normally have a coating that makes them very smooth, some also have an area around the forearm that helps in getting a good pull.
Obviously if you are swimming against a current you will be slower and with the current faster depending on how strong the current is. This can be slow to the point where you are getting nowhere or fast enough that you have to watch out that you don't crash into things e.g. buoys, boats and posts. This all makes for fun and interesting swimming.
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Old 09-14-2014
Talvi Talvi is offline
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Thanks Caro, I had been thinking that the turns in a pool would make pool times faster and pool distances feel shorter than in OW.

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Originally Posted by Caro View Post
... fast enough that you have to watch out that you don't crash into things e.g. buoys, boats and posts. This all makes for fun and interesting swimming.
LoL yes, I can imagine, and it may actually be that I'd experience swimming at almost elite speed, AND so pretty likely that in that euphoria I'd then crash!
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A psychological disorder is: "Any personal construction which is used repeatedly in spite of consistent invalidation."
~ George Kelly

"The water is your friend.....you don't have to fight with water, just share the same spirit as the water, and it will help you move."
~ Aleksandr Popov
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  #4  
Old 09-14-2014
Caro Caro is offline
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Some of the time gained in pushing off is offset by the time it takes to execute the turn.
Yes, going fast with the current is fun and takes so little effort.
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  #5  
Old 10-20-2014
danm danm is offline
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you're actually asking two very different things:
1. How will times in an ideal OW (basically just a very long pool) compare to your 25m pool. As a theoretical calculation this should be easy, just measure the swim speed that you can sustain for a duration similar to that of the crossing (say, 1hr for the bosphorus), estimate or measure how much time you gain or lose at each turn and from then on it's simple arithmetics. But I', afraid that is not going to help much.
2. How will you feel in OW compared to pool - this is harder, for two reasons. One is that you cannot remove conditions, waves, currents, etc from the equation. The second is that no one other than you can know how these things will affect you.

Since you ask what's other people's experience, to me the biggest difference in feel is that sometimes you can have a sense of no progress. This is the biggest issue in OW for me. It can be caused by currents, waves and poor orientation. I had it for a short while in the sea race; I just kept plodding and I started to get closer to the turning buoy, but in the Bosphorus it will be different, orientation is much more difficult.

So OW brings a whole new set of problems that are not related purely just to swimming.
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  #6  
Old 10-20-2014
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CoachStuartMcDougal CoachStuartMcDougal is offline
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This is actually quite simple to estimate OW pace from pool pace. Yes there is current and sighting, drift, bumping, etc. The primary one that is constant for all athletes is current - sighting and drift can be managed. I normally estimate my swimmers OW swim times (ocean and lake) within 2 mins and is primarily based on sustainable SPL and tempo. Depending on the swimmer and the course I will also factor wetsuit and expected currents, bumping at the start and at buoys, swimming slightly longer, i.e. 1.2 mile swim averages 1.24 for swimmers that drift little and slight course errors.

Here's a blog I wrote about it: Race pace without walls

Stuart
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  #7  
Old 10-21-2014
Talvi Talvi is offline
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Thanks Guys, very helpdul.

The Bosphorous idea is starting to feel like a fantasy, but I guess there's time yet.

I'm surprised though that current is such a biggie in OW gatherings. Aren't there always a flock of brightly bobbing caps to follow? Maybe that's only the case for manatee types though.

I imagine that being unfamiliar with swimming for so long and without the reassuring interruption of walls would be something new. In a way that's what I'm really looking but it also makes nervous. Giving up on reaching the end of a 2km+ swim in a pool, and being in the moment only on the current stroke, is not the same as doing so in the uninterrupted never-endingness of an hour.

I'll check out your blog Stuart. Thanks.
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A psychological disorder is: "Any personal construction which is used repeatedly in spite of consistent invalidation."
~ George Kelly

"The water is your friend.....you don't have to fight with water, just share the same spirit as the water, and it will help you move."
~ Aleksandr Popov
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  #8  
Old 10-21-2014
Caro Caro is offline
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Swimming 2 km in open water is much nicer than swimming in a pool, in fact the more open water swimming one does the less pool swimming one wants to do.
No nasty chemicals and interesting views and conditions.
Are there any open water swimming groups where you are? It's good to get a bit of practice with other people around, although this is probably not the best time of year to start. All of the open water swimmers I know are very welcoming and friendly and keen to encourage others to join them.
Human Race and Great Swim do some good events in the UK if you ever get over here, probably less intimidating than starting with the Bosphorous.
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  #9  
Old 10-21-2014
Penguin Penguin is offline
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As I recall, there is a 6 knot current running through the Bosphorous. Is there some special time or place where this can be avoided? Or is riding it all part of the fun?
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  #10  
Old 10-22-2014
danm danm is offline
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Quote:
Originally Posted by Penguin View Post
As I recall, there is a 6 knot current running through the Bosphorous. Is there some special time or place where this can be avoided? Or is riding it all part of the fun?
I think that current is what makes the crossing feasible for many, the current is mostly favourable. winner's times are in the low 40 minutes, without current this would be world record beating by a huge margin. also, the event is limited to two hours and many people of varied swimming ability are able to complete the 6.5 km in 1hr -1:15.

The problem is navigation, if you miss the favourable current you will end up swimming against it.
And, from water level, in waves, even moderate ones, you won't see many yellow caps bobbing around... and even if you do, how do you know they're going in the right direction? I think that unless you go with buddies and commit to staying together any such event should be approach as if you were on your own.

Last edited by danm : 10-22-2014 at 12:46 PM.
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