Rocket Ascents... Can divers breach like a fish (split from Accident in Mich)

[serambin]

Terminal velocity for a body in water is calculated to be around 1.4 * sq-rt LWL(or 6feet) in knots. This equals 3.94368 MPH or 5.78 ft / sec. To reach this velocity the only variable is the amount of force required to achieve the velocity. Better Ballistic coefficient = less force, but the terminal velocity is the same.

Stan

 

[Vtdiver2]

Just to add more ridiculousness...




100 feet in 10 seconds yields an AVERAGE velocity of 10ft/s.

But we're concerned with the INSTANTANEOUS velocity at the surface. However unlikely, it's possible that 9 of those 10 seconds were used up transversing the first 1 foot of the ascent.

At that point - taking into consideration another recent thread - the diver may have "passed wind" in a manner so extreme that, while it decreased the buoyant force (by virtue of the decreased volume of the intestines), it added substantial thrust (quite like a rocket engine), which was a function of the "wind's" density and velocity. Maybe the diver was born with a deformity, a convergent-divergent (De Laval) anus, that drastically accelerated the "wind," and propelled the diver the remaining 99 feet throughout the 1 second duration of the constant-force "wind passing."

Like I said... unlikely, but possible.

Uh, so...does that mean...er...you're saying that....if the diver had beans for lunch and passed gas while ascending, then he could get enough thrust to propel himself out of the water? Cool.
BTW I'm mastering in drinking a 6 pack of beer while reading this highly amusing thread.
Thanks for the entertaining evening.
Chris

 

[Vtdiver2]

I have seen the videos of guys in the training towers. 100ft and their feet are right the the waters surface, they have no wetsuit and no SCUBA gear, so I would think fins clearing are next to impossible.

Here is an old link:

http://www.scubaboard.com/archive/index.php/t-45913.html

I went to Submarine School while in the Navy back in the mid 80's, and they made us do an emergency ascent in a 100 ft tower. I didn't propel myself out of the water, but I might have peed myself :blush:
Chris

 

[Blackwood]

Airplanes also use this technique...vortex generators just aft of the leading edge of the wings in the form of a row of small 'blades' set at alternating slight angles to the airflow. They keep the flow attached a lot farther back toward the trailing edge at lower speeds.

Yah. I do airplanes for a living

 

[teknitroxdiver]

Yah. I do airplanes for a living

Ah....what kinds? Big/small, shiney/rusty, blue juice/amber juice?

 

[in_cavediver]

Terminal velocity for a body in water is calculated to be around 1.4 * sq-rt LWL(or 6feet) in knots. This equals 3.94368 MPH or 5.78 ft / sec. To reach this velocity the only variable is the amount of force required to achieve the velocity. Better Ballistic coefficient = less force, but the terminal velocity is the same.

Stan

Not quite. By you calcuation I can apply an infinite force and still not get past 4 mph. Trust me, if you take any of the other suggestions, such as the advanced skill of the underwater tank valve removal emergency ascent (Padi I believe has a card for this), you will most assuradly exceed 4 mph.

 

[Blackwood]

Ah....what kinds? Big/small, shiney/rusty, blue juice/amber juice?

Small, agile and packing heat.

 

[teknitroxdiver]

Small, agile and packing heat.

Ooooooooh...*eyes glossy*.....always nice when you have Government Approved Large Boom Producing Devices....

 

[Somethin-Fishey]

I went to Submarine School while in the Navy back in the mid 80's, and they made us do an emergency ascent in a 100 ft tower. I didn't propel myself out of the water, but I might have peed myself :blush:
Chris

Did you do it from the 100ft dimple? They only let us do it from the 40ft ledge. I went for DC Olympics frm Portsmouth Naval Shipyard. The video they showed us, definitely had people coming out of the water to their ankles/feet.

 

[serambin]

Not quite. By you calcuation I can apply an infinite force and still not get past 4 mph. Trust me, if you take any of the other suggestions, such as the advanced skill of the underwater tank valve removal emergency ascent (Padi I believe has a card for this), you will most assuradly exceed 4 mph.

Sorry, the terminal velocity holds for any displacement body including a nuclear powered sub. The only way around this is to plane an object. The speed for a 6' person is 5.78 feet /second. If you can beat that, DOD needs you.

Stan