archer1960
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You would have to use a non-compressible flotation material, like light wood, etc.
Fine tuning of buoyancy distribution.
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uhhh what? You aren't moving fast enough for the low pressure zone caused by the bottom of a flat bottom tank or the tank boot to cause any significant drag.... Certainly not meaningful enough compared to a jacket style BC... try again. There is 0 need for a tank float, something is wrong with your configuration....
You have no idea how fast I'm moving. You should be careful about assuming you know more about my diving configuration than I do. My equipment is custom made to allow swimming at high speeds.
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doesn't matter, you still can't swim fast enough to where the drag caused by a negative pressure zone created by a 8" max diameter circle is going to be significant. You have to be going faster than any human can swim and if you're concerned about it, just buy steel tanks with round bottoms...
I think Revan is one of the crazy fin guys (don't get angry about this term), so they can be going pretty fast. Fast enough for it to be a concern? Not sure though. (I don't give a damn about serious hydrodynamics)
OTOH, even some pretty slow fish are still fish-shaped to allow for a better water penetration...
Bob DBF
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Try this company to put it together.
http://deepwaterbuoyancy.com/product-sheets/rovits-deepwater-buoyancy.pdf
They can custom make floatations to use at any depth for whatever reason you might want.
I think it would be expensive and overkill when there are other, less expensive, ways to deal with the issue and some of which are on this thread.
Bob
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yes, but the point is the negligible reduction from the bottom of an aluminum tank is offset by the following.
Any gas in the wing
the front of the divers body
any bc that you're wearing unless it is a wingless straight webbing harness like the military used to use with no plate or anything, just is completely and utterly pointless to think that a diver moving as slow as we do is going to benefit from reducing the drag created by the low pressure space behind the tank when there are so many other things creating much more drag that can't realistically be overcome. You're going to give less than a foot per minute of speed, or extend range by maybe a hundred yards, you're still on an aluminum tank that isn't going to take you very far, and even an increase of 5fpm isn't going to matter.
Alternatively, instead of spending an idiotic amount of money on some floaty tank boot, I can buy a LP72 on craigslist for less than $100, shed 5lbs from my weight belt, as well as reducing the overall mass of the rig. AND I go from a flat bottom to a rounded bottom thus negating the need for some funky tank boot that is going to remove your ability to set the tank down on anything
Any gas in the wing
the front of the divers body
any bc that you're wearing unless it is a wingless straight webbing harness like the military used to use with no plate or anything, just is completely and utterly pointless to think that a diver moving as slow as we do is going to benefit from reducing the drag created by the low pressure space behind the tank when there are so many other things creating much more drag that can't realistically be overcome. You're going to give less than a foot per minute of speed, or extend range by maybe a hundred yards, you're still on an aluminum tank that isn't going to take you very far, and even an increase of 5fpm isn't going to matter.
Alternatively, instead of spending an idiotic amount of money on some floaty tank boot, I can buy a LP72 on craigslist for less than $100, shed 5lbs from my weight belt, as well as reducing the overall mass of the rig. AND I go from a flat bottom to a rounded bottom thus negating the need for some funky tank boot that is going to remove your ability to set the tank down on anything
tbone1004: A round bottom doesn't really save you on any drag. It contracts too fast and the water separates almost immediately. It requires a more gradual contraction to recover form drag from a tank.
Like most divers, it seems you have the "it just doesn't matter" attitude. I aim to educate divers that it does matter and prove that the quest is not futile and remind divers that swimming performance is important to both the comfort and safety of dives and to scuba diving being a viable technology for ocean exploration.
When ready, I'll likely be opening a thread on SB regarding the work I have done on swimming performance for scuba divers. Speeds that most divers think are unobtainable are actually possible with some attention to hydrodynamics. Also, my tank will stand on the tailcone, unlike a round bottomed steel tank which won't stand at all without a boot to make it flat ended.
I like steel tanks, especially the HP tanks. They are much smaller and more volume efficient than aluminum tanks. However, I'm presently restricting my experiments to using standard AL 80 tanks like you'd get if you went into a dive shop in Fiji, Mexico, or Vanuatu and asked to rent a scuba tank. I'm going to pick up the tanks that are available where I'm traveling and will not be taking specialty tanks with me when traveling to exotic destinations. I want my diving to be easy and fun, not a logistical or physical ordeal.
Like most divers, it seems you have the "it just doesn't matter" attitude. I aim to educate divers that it does matter and prove that the quest is not futile and remind divers that swimming performance is important to both the comfort and safety of dives and to scuba diving being a viable technology for ocean exploration.
When ready, I'll likely be opening a thread on SB regarding the work I have done on swimming performance for scuba divers. Speeds that most divers think are unobtainable are actually possible with some attention to hydrodynamics. Also, my tank will stand on the tailcone, unlike a round bottomed steel tank which won't stand at all without a boot to make it flat ended.
I like steel tanks, especially the HP tanks. They are much smaller and more volume efficient than aluminum tanks. However, I'm presently restricting my experiments to using standard AL 80 tanks like you'd get if you went into a dive shop in Fiji, Mexico, or Vanuatu and asked to rent a scuba tank. I'm going to pick up the tanks that are available where I'm traveling and will not be taking specialty tanks with me when traveling to exotic destinations. I want my diving to be easy and fun, not a logistical or physical ordeal.
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@REVAN I think the point is most of us believe we don't want to swim fast while on scuba. It burns air faster, you see less stuff, and other than fighting currents, serves very little purpose. In that regard, hydrodynamics simply don't matter much, despite all the "streamlined" nonsense you read on scubaboard. That's mostly about not dragging stuff on the bottom/reef rather than actual swimming efficiency.
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