Question on streamlining

[Mako Mark]

del

it does look cool huh?

when you can make the distinction of letting your activity rate dictate your respiratory rate, and making your rispriatory rate dictate your activity rate, then you will be able to streamline properly.

but this is rather advanced.

not many divers can do this, even the DIR crowd.

 

[wreckchick]

Frog-kicking, which I believe is what we're talking about here for me is a more powerful kick that will propel me forward while allowing a brief rest between kicks. If I flutter kick, I'm moving the whole time which is inefficient. It's also an anti-silting technique. Even from several feet above the bottom a flutter will kick up some silt while a frog-kicker can be inches above the bottom and leave it undisturbed.... and it looks cool.

Cancun mark, I'm not sure what you're getting at with that last post. If you mean that as a diver you want to keep a certain activity level that's consistent with a breathing pattern? Working to not overbreathe your regs? I'm not sure why someone can't work to properly streamline without doing whatever it is you mention.

Original question.... streamlining puts all the pieces of your rig in the same place every time which gives you better access to your stuff, it reduces the effort of swimming by reducing drag which in turn reduces air consumption, and it addresses entanglement issues by working to reduce the number of possible snag points.

Rachel

 

[TeddyDiver]

Along this same vein, what has perplexed me on streamlining is watching tech or other talented divers cruise along (how I wish I could do what they do, and I try and try and try) with their knees bent and their lower legs vertical. To me this is very unstreamlined and doesn't make sense in a no-silt situation. Am I missing something here? Are we talking about giving up just a couple breaths of air? Is it because the kick is more effective and offsets the drag? Do they do it because they can and it looks cool and it shows a level of competence?

It's due the drag of lowerlegs vs drag of fins, and with froggy turning fins to kick affects less drag in this position..

 

[Jason B]

Let me add one more spin on the whole streamlining concept that I don't think has been mentioned, but may help the OP see an advantage.

Diving into a current. If you are not streamlined, you will experience serious resistance and use oodles of energy/gas.

 

[spectrum]

I read a lot of references to streamlining whenever there are equipment questions usually in relation to hoses and Jacket vs BP/Wings.

Why is streamlining so important? I can understand streamlining for say, car racing or flying where speed and fuel consumption are critical issues. But is it so crucial in diving? And if it is, then why?

As mentioned it's all about the density of water combined with the limited breathing resource. It's not like you can huff and puff and still enjoy a long dive.

Forget about counting hoses, if that were important half the people on this board would not be advocating a double length primary hose.

Dive a properly sized BC. Jacket or wing I don't care. An overly large wing can be worse than almost any BC. Many BCs will be more streamlined than any wing regardless of what you see on your chest.

Have your alternate air source and instruments rigged so they are close to you, breaking through the water as one. Same for lights, sausages slates and so fort. If it's not a needed item don't even bring it. Note that a safety item may be needed even though you hope to not use it.

Think torpedo, make sure you are in good trim so that you move straight through the water, feet neither low nor high.

Pete

 

[ScottB]

I *think* Del_mo might be talking about the bent leg flutter kick.. but I am not positive.. =) (knees close to a 90 degree angle and rigid, using same muscle groups as flutter kick)... for passages too narrow to use standard frog kick while still attempting to avoid silting up the floor..

In which case, and in most cases, I've found making really small frog kicks works well for me.. almost exclusively using my ankles...

 

[scuba-charters]

Look at the winning swimmers... They go to the point of shaving their body and head to reduce friction... extreme, but it makes a difference in the water.

 

[Bob3]

I forget the exact formula, but as speed increases, drag increases at some inverse proportionate ratio. It's not a direct linear equation.
The faster you go (or the stronger the current), the more important it becomes to reduce drag as much as possible. (think scootering & strong current diving).

 

[del_mo]

What I was trying to describe is the style used in cave diving. I'm not sure what I found more fascinating, seeing the Cenotes in Mexico, or watching the dive leaders. Poetry in motion. What made me ask the question was seeing the same techniques used during reef dives.

 

[Xman]

I forget the exact formula, but as speed increases, drag increases at some inverse proportionate ratio. It's not a direct linear equation.
The faster you go (or the stronger the current), the more important it becomes to reduce drag as much as possible. (think scootering & strong current diving).

If only that were true, then the faster we went the less drag we would have. Nevermind, I know what you're getting at, but I think you'll find that drag increases exponentially with speed rather than at some inverse proportional ratio.