Collapse of Submarine Pressure Hulls'

1
Collapse of Submarine Pressure Hulls.

• By
• Carl T.F.Ross
• University of Portsmouth

2
THE OCEANS

• ¾ of the Earths surface is covered by water.
• The Earths surface covered by water is over 10
  times larger than the surface area of the Moon !
• The greatest depth of the oceans is found in the
  Marianas Trench this is 11.52 km (7.16 miles)
  deep.
• The Marianas Trench is some 30 deeper than the
  height of Mount Everest !

3
MILITARY USE OF THE OCEANS

• The oceans have great military value.
• Missile launching platforms are likely to be
  placed on the ocean bottoms.
• Radar does not work underwater.
• Heat seeking missiles do not work underwater.
• Satellite spy cameras are ineffective when a
  submarine dives very deep into the oceans.

4
OCEAN RESOURCES

• Methane deposits in the form of hydrates have
  been found at water depths of 2 miles (3.2 km)
  and more.
• Off the coasts of the USA, 30 gas fields have
  been found.
• In one gas field alone, it is believed that
  there is sufficient gas to satisfy the USAs
  needs for 105 years, based on their 1996
  consumption rate.
• Deposits of precious metal and minerals have also
  been found on the ocean bottoms.

5
OCEAN PRESSURES

• At the bottom of the Marianas Trench, the
  pressure is about 1158 bar (16,800psi).
• Currently, a large submarine can only dive to a
  depth of about 400m (1310 ft).
• The construction of a large submarine pressure
  hull for very large depths is not easy.

6
Shell instability an undesirable mode of
failure.
7
Buckling of a circular cylinder under an internal
vacuum by shell instability.
8
Axisymmetric yield, where the pressure hull
implodes inwardly, keeping its circular form.
9
To avoid shell instability, and improve the
structural efficiency of pressure hulls, the
vessels are usually ring-stiffened.
10
If the ring-stiffeners are not strong enough, the
vessels can buckle bodily through general
instability.
11
HISTORY OF SUBMARINES
12
The First Submarine, built by Alexander the
Great, was called Colimpha, (356-323 BC).
13
An Idea by William Bourne (1578) Not Built
14
A Cartoon of Drebbels (a Dutchman) invention
built between 1620-1624 in London.
15
Bushnells TURTLE, built to fight the British in
Americas War of Independence.
16
The HOLLAND 1, built by John Holland an
Irish-American school teacher at the end of the
19th century.
17
Britains First Nuclear-Powered Submarine -HMS
DREADNOUGHT
18
Auguste Piccards Trieste

• On 23rd January 1960, Piccard conquered the
  Marianas Trench with his submarine the Trieste
  1.
• Its pressure hull was a thick-walled spherical
  shell of 6ft diameter and 6 ins thick.
• It was made of high-tensile steel
• The pressure hull had no reserve buoyancy and to
  give it reserve buoyancy, it required a large
  float filled with gasoline, so that it could
  resurface when required.

19
The Trieste 1.
20
Jacques Piccard Lt Donald Walsh (US Navy),
inside the Trieste 1, prior to making their
record breaking dive.
21
Underwater Methane Deposits.

• Many eminent scientists believe that there are 10
  000 billion tonnes of methane buried under the
  sea floors in the oceans deep.
• Much of this methane is frozen.
• If this methane is distributed equally among all
  people on Earth, each one of us will get a 1670
  tonne chunk of methane, which on current UK
  prices will be worth about 1,250,000 per person!

22
Underwater Methane Deposits.

• Many eminent scientists believe that the
  temperature of the oceans has increased by about
  0.5 to 1.0 degree Celsius, since 1960.
• If global warming continues the seas will
  continue to warm up.
• If the temperatures of the seas gets sufficiently
  high the frozen Methane can evaporate and catch
  alight.
• A gas field that catches alight can burn for
  about 100 years or more!

23
Underwater Methane Deposits.

• Thus, it will be necessary to use the underwater
  methane to prevent it from catching alight.
• The methane can be collected by drilling a hole
  into the reservoir containing methane gas and
  sucking the gas out, as shown by the next slide
  (Blake Ridge, USA).
• This will cause the pressure to fall in the area
  where it is frozen and cause the frozen methane
  to vaporize from this compartment into the
  reservoir immediately below.
• The process can be repeated until all the frozen
  methane from the compartment above has
  eventually vaporized into the reservoir below.

24
Methane Collection (mbsfmetres below sea floor).
25
The map shows that the USA Japan are searching
for stores of the deep sea gas but not Europe!
26
Carbon dioxide burial can also take place in the
deep oceans (mbsfmetres below sea floor).
27
Underwater drilling rig for methane retrieval
carbon dioxide burial.
28
CONCLUSIONS

• It is likely that in the future many submarine
  pressure hulls will be constructed in man-made
  materials, such as glass, boron and carbon fibres
  and ceramic and metal-matrix composites.
• Submarines constructed in man-made fibres will
  lend themselves to be readily constructed in the
  novel forms described here.

29
REFERENCES

• Ross, C.T.F Pressure Vessels External Pressure
  Technology, Horwood Publishing, Chichester,
  2001. ISBN 1-898563-74-8.
• http//homepage.ntlworld.com/carl.ross/page3.htm
• Email carl.ross_at_ntlworld.com