|
Hi Alan,
If it's a K-250 you're building, here's your other
data point. I just weighed the hatch, and it's 23.5 kg. So it would be 6.5 kg
buoyant.
Alec
Hi thanks people,
I was having trouble understanding this. I just put plastic wrap loosly
over the top of a glass & submerged it. Some of
the wrap bulged up
but you could push parts down below the level of
the top of the glass.
( This proves you right )
I am going with a dome hatch, but
haven't designed the locking mechanism yet.
The dome will be close to 30kg of boyancy
before its mounted.
Alan
----- Original Message -----
Sent: Thursday, February 18, 2010 6:51
AM
Subject: RE: [PSUBS-MAILIST] Hatch
pressure
First weigh the hatch in air. Then calculate the
displacement of the hatch, which is the weight of the water that would fill an
equivalent volume. Subtract the displacement from the weight. If you get a
negative number, the hatch will tend to "float" as you describe. I doubt very
much that would be the case for any conventional elliptical steel
hatch. In the case of an acrylic dome hatch like the K-250, I'd recommend
doing the math because I'm less sure of the outcome -- those might
be slightly buoyant.
Alec
The contents of this e-mail are
intended for the named addressee only. It contains information that may be
confidential. Unless you are the named addressee or an authorized designee,
you may not copy or use it, or disclose it to anyone else. If you received it
in error please notify us immediately and then destroy it.
Hi all,
I've brought up this subject before, but are
tackling it from a differant angle.
How much pressure is exerted upward on a hatch
at the moment where the
submarine
just submerges below the water? This is the point
of most force before external water
pressure helps close it.
If you took your submarine, filled it with water
& hung it upside down, would this be the
same amount of force, or close to
it.
In wich case if you have a design like Franks
flying saucer that angles up to the hatch,
you'd have a lot more force acting upward on the
hatch than a K250 where the lifting force
would be spread more evenly along the
hull.
Am I thinking right?
Alan
|