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

[Rec Diver]

Is it possible to breach? Yes ...

Is it possible to breach to the point of becoming airborne? I don't think so.

And yes, the weight of your scuba gear will pull you down the instant you break the surface, and the drag will slow you down significantly before you get there.

A little "safe" experiment for ya ... go skin diving. Dive down as deeply as you can, then propel yourself toward the surface as hard and fast as you can. See how far out of the water you can force yourself to go.

Betchya you can't force yourself completely outta the water ... even without the weight and drag of scuba equipment ... and if you claim otherwise, I want to see the video ...

... Bob (Grateful Diver)

I am going to send you a private e-mail in regards to your request.

 

[pants!]

No. Bob is correct, it is almost 6 mph, actually 5.65 mph.

For an object to be projected 5 feet into the air against the force of gravity, it needs an initial velocity of about 17 feet per second, or 1073 feet per minute, or 12 mph

By comparison, the fastest swimmers on earth go just over 5 mph.

I'd like to see where you got 6 mph. My calculation was done as follows:

h = Vo^2 / 2*g, where h is the maximum height reached, Vo is the velocity upon breaching the surface, and g is the acceleration due to gravity.

5 ft = Vo^2 / (2*32 ft/s^2)

Vo solves to 17.89 ft/s, which is about 12 mph.

 

[Charlie99]

A little "safe" experiment for ya ... go skin diving. Dive down as deeply as you can, then propel yourself toward the surface as hard and fast as you can. See how far out of the water you can force yourself to go.

Betchya you can't force yourself completely outta the water ... even without the weight and drag of scuba equipment ... and if you claim otherwise, I want to see the video ...

12mph is really, really good, even for a skindiver. Maybe when a Great White is coming after the fish you just speared ......

 

[Rick Murchison]

water pressure reduces as we ascend...increasing the velocity

And now I understand.....
Rick

 

[MXGratefulDiver]

For an object to be projected 5 feet into the air against the force of gravity, it needs an initial velocity of about 17 feet per second, or 1073 feet per minute, or 12 mph

By comparison, the fastest swimmers on earth go just over 5 mph.

I'd like to see where you got 6 mph.

From here ... http://www.scubaboard.com/showpost.php?p=1253255&postcount=21 ... which was only a random example.

Your calculations are correct, as near as I can tell ...

... Bob (Grateful Diver)

 

[Uncle Pug]

And now I understand.....
Rick

 

[cmalinowski]

For an object to be projected 5 feet into the air against the force of gravity, it needs an initial velocity of about 17 feet per second, or 1073 feet per minute, or 12 mph

By comparison, the fastest swimmers on earth go just over 5 mph.

I'd like to see where you got 6 mph. My calculation was done as follows:

h = Vo^2 / 2*g, where h is the maximum height reached, Vo is the velocity upon breaching the surface, and g is the acceleration due to gravity.

5 ft = Vo^2 / (2*32 ft/s^2)

Vo solves to 17.89 ft/s, which is about 12 mph.

Yes, but is that an "african swallow" object or a "European swallow" object?

 

[Rec Diver]

For an object to be projected 5 feet into the air against the force of gravity, it needs an initial velocity of about 17 feet per second, or 1073 feet per minute, or 12 mph

By comparison, the fastest swimmers on earth go just over 5 mph.

I'd like to see where you got 6 mph. My calculation was done as follows:

h = Vo^2 / 2*g, where h is the maximum height reached, Vo is the velocity upon breaching the surface, and g is the acceleration due to gravity.

5 ft = Vo^2 / (2*32 ft/s^2)

Vo solves to 17.89 ft/s, which is about 12 mph.

Using NWGrateful Divers original example of 83 feet in 10 seconds. Here is the formula. Remeber though, we are converting this to MPH. 83 feet per 10 seconds equals 8.3 feet per second. Now multiply 8.3 by 60 (converting to minutes), this equals 498 feet per minute. Now multiply 498 by 60 (converting to hour), this equals 29,880 feet per hour. Now to convert to miles per hour divide 29,880 feet by 5280 (this how many feet there is in a mile) and you get 5.65 miles per hour. I know it is not as fancy as yours, but I think it is a little more accurate.

 

[pants!]

83 feet in 10 seconds does indeed give you 5.65 (well, 5.66) miles per hour.

That has no bearing on how much it actually takes you to breech the water, though.

This is the dumbest argument I've ever heard.

 

[TorontoDive]

And now I understand.....
Rick

Seriously....somebody must've failed physics to be factoring in water pressure :06: