Dynamic on the bottom of a pool V's midwater dynamic

[pelagicbeing]

My apologies if this has been discussed before / or if i am making a very obvious observation etc.

I have been training dynamic regularly 4x a week in my local pool and some days i get to use the shallow pool 1.2mtrs or so deep, and some days i get to use the training pool 3.00 mtrs deep.

I am using short rubber training fins with a dolphin kick to help my improve my overall monofinning ability in the sea at the weekends. I have started to notice now that the school holidays are here, and i am relegated to the shallower pool more, that dynamic seems easier and appears to require less effort than in the deeper pool.

The only difference being that in the shallow pool i swim with about 30cm's between me and the pool bottom, and in the deeper pool i swim with at least 100cms between me and the pool bottom.

I have noticed that when dolphin kicking close to the bottom in the shallower pool that i seem to be getting benefits from the downward 'stroke' as the water is displaced and then hits the bottom and giving me what appears more forward movement. If i really concentrate it feels like my body is riding a pressure wave sandwiched between me and the bottom.

I am not a scientific type, and this kind of technical detail doesn’t really excite me being a recreational freediver only , but i just wondered if anyone had noticed a significant difference in dolphin kicking close to a fixed surface as opposed to dolphin kicking in relatively open water conditions? or am i turning into an aquatic nerd?

pelagicbeing

[naiad]

I find all kinds of dynamic easier if I am as close to the bottom of the pool as possible. Don't know the science behind it though...

[jome]

Have you timed your swims?

I get a very strong subjective feeling that swimming close to the bottom goes more smoothly. But if I compare the times of similar swims near the surface, they are almost identical and no clear trend one way or the other.

I'm not saying that swimming close to the bottoms does not have hydrodynamic effects, but at least in my case, the "feeling of efficiency" comes mostly from the fact that the closer you look at the tiles from, the faster they seem to move. Thus, swimming close to the bottom I feel like I'm really flying and close to the surface I feel like I'm not going anywhere. But the objective truth of the merciless clock indicates that there is in fact no real difference at all...

[ggarrett]

Originally Posted by pelagicbeing

My apologies if this has been discussed before / or if i am making a very obvious observation etc.

Try http://forums.deeperblue.net/showthread.php?t=33274& It has a good discussion of this topic.

I believe that the bottom can have a positive effect on dynamic, even without fins.

A challenge in dynamics is to swim level with relation to the surface in order to minimize the distance, say, like a meter below. Minimizing distance is especially a factor in pools that go from a shallow end to the deep end where the tendency is to follow a longer bottom route.

Peace,
Glen

[pelagicbeing]

Thanks for the feedback guys, good previous thread on this topic (couldn’t seem to find it initially )

Your right Jome it could well be the psychological aspect of having tiles apparently going faster past you (they are beautifully hypnotizing aren’t they ), but there was a distinctive ease when i hit the sweet spot, and the feeling of allot less exertion at the end, although that is obviously totally subjective.

The times are relatively similar, and as i said was only curious as to whether any one else had experienced this as well. My objective is not distance but the to increase the ease and relaxed state i achieve whilst using a monofin, so that i scare less off before i see it in the sea! (and it just feels nice! ).

Thanks

pelagicbeing

PS. did you know that there is an old 'shamanic' germanic art called Seidr, which uses a method called 'seething' to enter trances and 'journey' which involves spontaneous movements some similar to monofinning motion....but thats another thread all together

[watts]

I tend to travel very close to the bottom for some reason, It does seem easier and keeps you away from breaking the surface for comps.You do tend to bang the knees though.

[pelagicbeing]

Originally Posted by watts

I tend to travel very close to the bottom for some reason, It does seem easier and keeps you away from breaking the surface for comps.You do tend to bang the knees though.

On the other hand, with a monofin / dolphin kick motion, it would make your movements more refined with the incentive to not use the knees too much....

[Almostafish]

The affect is called Squat.. It happens to ships as they travel faster the draught is reduced due to pressure highs and lows around the hull, and the same is happening when your high pressure bow wave interacts with the bottom of the pool.. Its all to do with boundry layers but lets not bother with that!

[pelagicbeing]

I keep on asking my 'high pressure bow wave' to stop interacting with the pools bottom.....its just damn inappropriate in a such a public place!

Thanks for the explanation.

pelagicbeing