What water sees.

[rx7diver]

Test driving a new piece of software, I drew the attached graphic, which might generate an interesting discussion here.

Safe Diving,

rx7diver

P.S. I've included the code in case someone else wants to play.

EDIT: Graphic won't upload. I'll try again later.

It's here now. The thick-wetsuit-ed diver on left is wearing a Scubapro Stabilizing Jacket (SSJ), inflated at depth to compensate for a single full, heavy steel cylinder. The thick-wetsuit-ed diver on the right is wearing a conventional BP/W, inflated at depth to compensate for a single full, heavy steel cylinder. Both divers are swimming side by side, coming toward you, the viewer. To keep things simple, I didn't include lower legs and fins.

 

[kelemvor]

P.S. I've included the code in case someone else wants to play.

Source code?

 

[rx7diver]

Source code?

Yes. Mathematica. Here you go:


Print[Style["What the Water Sees: ",18,Blue], Style["SSJ vs. BP/W", 18, Purple]]
ContourPlot[{

((x-{25,75})/{15,15})^2 + ((y-{50,50})/{5,5})^2==1,
((x-{25,75})/{3.625,3.625})^2 + ((y-{59,60})/{3.625,3.625})^2==1,
((x-{25,75})/{4.25,4.25})^2 + ((y-{54,54})/{4.25,4.25})^2==1,
((x-{25,75})/{4.25,4.25})^2 + ((y-{54,54})/{2,2})^2==1,

((x-25)/15)^2 + ((y-50)/6)^2==1,

((x-{70,80})/{2,2})^2 + ((y-{57,57})/{2,2})^2==1,

yŠ=25}, {x,0,101},{y,0,101},Epilog{(Text["Is one better than the other?",{50,27}]),(Text["SSJ",{25,40}]),(Text["BP/W",{75,40}])},

PlotLabel®"What the Water Sees"]


Be careful. Some of the special characters might not have printed correctly.

I will try again to upload the graphic later this evening/tonight.

EDIT: It's there now.

Safe Diving,

rx7diver

 

[Doby45]

Aliens because apple taste like purple.

 

[Storker]

Sorry, you have to provide more context if I'm supposed to understand what your thesis is.

 

[rx7diver]

Sorry, you have to provide more context if I'm supposed to understand what your thesis is.

Storker,

No "thesis" per se. Just another look, comparing jacket BC's vs. BP/W for recreational diving. Scale might be a bit off, but here are a couple of things to consider:

1. Jacket BC diver slightly poofs out his/her BC (i.e., grows slightly bigger in cross-section around his torso) to provide additional buoyancy. Contrast the inflated Wing of the BP/W diver.

2. When swimming horizontally, less of the jacket BC diver's tank is presented to the water (since his tank is blocked more by his head). By contrast, more of the BP/W diver's tank, sitting higher off the diver's back due to the conventional plate, is presented to the water.

3. Does one diver appear to be more hydrodynamic than the other?

4. Does one diver appear to be more "stable" (i.e., less top heavy) than the other?

5. Old-school oval masks are easy to graph!

6. Do these two graphics suggest anything to you re your own configuration?

7. (More.)

Safe Diving,

rx7diver

 

[Pinecube]

I see it now, the circles and bubbles are showing a front-facing view of a diver in horizontal trim.
To me it seems like the BP/W is shown as fully inflated yet the jacket style BCD is minimally inflated?

 

[rx7diver]

I see it now, the circles and bubbles are showing a front-facing view of a diver in horizontal trim.
To me it seems like the BP/W is shown as fully inflated yet the jacket style BCD is minimally inflated?

Pinecube,

This is the part that is not so obvious, I think. You increase buoyancy by displacing more water (with air). The fact that the jacket BC poofs out around the entire torso (from the diver's front, from his/her back, and under both arms), it really doesn't need to poof out very much to supply a lot of buoyancy.

I was actually going to compute and sketch the "correct" amount of poof required in the jacket BC, to match the oval Wing shown (the tube has a 2 in radius). All that's required is a couple of simplifying assumptions. But I decided to have a beer, instead.

Safe Diviing,

rx7diver

 

[tursiops]

Storker,

No "thesis" per se. Just another look, comparing jacket BC's vs. BP/W for recreational diving. Scale might be a bit off, but here are a couple of things to consider:

1. Jacket BC diver slightly poofs out his/her BC (i.e., grows slightly bigger in cross-section around his torso) to provide additional buoyancy. Contrast the inflated Wing of the BP/W diver.

2. When swimming horizontally, less of the jacket BC diver's tank is presented to the water (since his tank is blocked more by his head). By contrast, more of the BP/W diver's tank, sitting higher off the diver's back due to the conventional plate, is presented to the water.

3. Does one diver appear to be more hydrodynamic than the other?

4. Does one diver appear to be more "stable" (i.e., less top heavy) than the other?

5. Old-school oval masks are easy to graph!

6. Do these two graphics suggest anything to you re your own configuration?

7. (More.)

Safe Diving,

rx7diver

1. Why? Is this not a function of weighting and bladder sizes?
2. So?
3. No. And even if one did, *which* would depend totally on relative sizes of things, weighting, and the way you've drawn the picture.
4. No. How can you estimate "stability" without knowing weights (in water), ceters of buoyancy and gravity, etc?
5. Yes.
6. No. What they suggest to me is you have some point your are trying to make, some point-of-view you are trying to promote. What is it?
7. I hope not.

 

[rx7diver]

1. Why? Is this not a function...

tursiops,

This precisely is the value, and fun (in my opinion), of these types of discussions/exercises. Anyone can assign different values to the parameters and thereby gain insight by the effects that obtain. Helps inform the discussion. No absolutes, correct?

Safe Diving,

rx7diver