Note: Descriptions are shown in the official language in which they were submitted.
CA 02439844 2003-09-05
Submarine Emergency Evacuation System
Field of the Invention
The invention relates generally to evacuation systems for offshore fixed
structures or vessels, and more particularly to submarine evacuation systems.
Background of the Invention
Current approved emergency evacuation systems for the international offshore
1 o are categorized as dry, semi-wet, and wet systems. Dry systems, such as
helicopters,
are the preferred alternative since personnel do not come into contact with
the ocean
environment. Nevertheless, such systems have limitations as unfavourable
atmospheric conditions such as wind, fog, rain, freezing rain, icing or snow
often
preclude air-borne rescue. Unfortunately, these conditions are normally
present when
15 offshore installations are at peril.
Semi-wet systems, such as Totally Enclosed Motor Propelled Survival Craft
(TEMPSC) and life rafts, are required on all offshore structures and do not
always do
what is expected of them. Though essential, these systems also have
limitations. A
2o TEMPSC launch from a rig can be perilous in severe weather conditions, and
huge
waves are often a mortal threat to these crafts.
Wet systems, such as lifejackets and immersion suits, act as a backup to dry
and semi-wet systems. They are the Escape, Evacuation and Rescue (EER) of last
25 resort and are used only if personnel are forced into the ocean. All EER
systems in
use today share a common element in that the final evacuation must be carried
out by
either air or surface craft. In most emergency evacuations, atmospheric or
water
surface conditions are extreme posing severe threat to human life.
3o Therefore, there is a need for an evacuation system capable of operating in
various types of emergency situations, under extreme environmental conditions.
Summary of the Invention
The invention is directed to an evacuation system for an offshore unit.
35 The evacuation system comprises at least one submarine evacuation module
attached
to the offshore unit.
CA 02439844 2003-09-05
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In accordance with a specific aspect of this invention, a submarine evacuation
module comprises a submarine for transporting personnel to be evacuated and a
watertight submarine bay fixed to the offshore unit for holding the submarine,
the bay
having a door to permit the launch of the submarine from the bay. The
evacuation
system may further include a shaft connecting the submarine bay to a
predetermined
location on the offshore unit to provide the personnel access to the submarine
bay.
In accordance with a further aspect of the invention, the submarine evacuation
1o module is attached to the offshore unit below the water level; the
evacuation module
may be located within or above a pontoon of a semi submersible offshore unit,
or
within a hold of a vessel offshore unit.
With regard to specific aspects of the invention, the evacuation module bay
15 includes a mechanism for flooding the submarine bay and for operating the
door, a
hook mechanism for coupling the submarine to the submarine bay and a control
system for operating the flooding, the door operating and the hook mechanisms.
The
evacuation module bay may also include a roller system for cradling the
submarine
and guiding its movement into and out of the bay, and a sonar system for
detecting
20 obstructions near the bay door outside of the bay.
In accordance with another aspect of the invention, the evacuation module
includes a flexible tube for connecting a universal mating system hatch on the
submarine to a hatch on a wall of the submarine bay to provide a watertight
passage
25 from the submarine bay hatch to the universal mating system submarine
hatch. The
hatch may also include a switch for activating the control system.
In accordance with another aspect of this invention, the submarine includes a
connector for coupling the submarine to the hook mechanism, wherein the
connector
3o includes a U-bolt adapted to be sheared from within the submarine. In
addition, the
submarine may include a control system for directly operating the flooding and
the
door operating mechanisms.
Further, this invention is directed to a method of evacuating personnel from
an
35 offshore unit having a portion adapted to be submerged below the water
level,
wherein the offshore unit includes at least one submarine module having a
submarine
CA 02439844 2003-09-05
held within a watertight submarine bay; the method comprises having the
personnel
enter the submarine, flooding the bay, opening the door in the submarine bay
and
propelling the submarine from the bay to a predetermined location remote from
the
offshore unit.
In accordance with a further aspect of this invention, the first step of the
evacuation method may include having the personnel gather at a muster station,
counting the personnel gathered, checking the submarine and having the
personnel
enter the submarine.
In accordance with another aspect of this invention, the first step of the
evacuation method may include having the personnel gather at a muster station
on a
deck of the offshore unit, counting the personnel gathered, having the
personnel
proceed to a muster station at the submarine bay, counting the personnel at
the
1 s submarine bay muster station, checking the submarine and having the
personnel enter
the submarine.
Other aspects and advantages of the invention, as well as the structure and
operation of various embodiments of the invention, will become apparent to
those
ordinarily skilled in the art upon review of the following description of the
invention
in conjunction with the accompanying drawings.
Brief Description of the Drawings
The invention will be described with reference to the accompanying drawings,
wherein:
Figure 1 illustrates a schematic view of a semi-submersible drilling rig;
Figure 2 is a cross-section side view of an evacuation system module;
Figure 3 is a cross-section front view of the evacuation system module;
Figure 4 shows the location of the evacuation module in accordance with the
3o present invention over a pontoon of the drilling rig;
Figure 5 shows the location of the evacuation modules in accordance with the
present invention within a pontoon of the drilling rig;
Figure 6 illustrates, in top view, the location of the evacuation modules in
or
on the pontoons of the drilling rig;
Figure 7 schematically illustrates the location of the evacuation modules in
accordance with the present invention within a vessel;
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Figure 8 illustrates the Universal Mating System (UMS) for the evacuation
module in figure 5;
Figures 9a, 9b, 9c illustrate in front view, side view and top view a sliding
door arrangement for the evacuation module in figure 5;
Figures 10 a and l Ob illustrate the seal between the tube door and the vessel
hull for the evacuation module in figure 7;
Figure l la and 1 lb illustrate the submarine hold-fast hook for the
evacuation
module in figure 5;
l0 5;
and 6;
5;
Figure 12 illustrates the submarine U-bolt for the evacuation module in figure
Figure 13 illustrates the roller system for the evacuation module in figures 5
Figure 14 illustrates the a hydraulic system for the evacuation module in
figure
15 Figure 15 illustrates a manual override system for the evacuation module in
figure 5; and
Figures 16a and 16b illustrate the evacuation process using an evacuation
module in accordance with the present invention.
2o Detailed Description of the Invention
A submarine evacuation system in accordance with the present invention will
be described in conjunction with semi submersible drilling rig 1 of the type
shown in
figure 1. However, it will become clear that the invention can also be used
with any
type of structure or vessel that operates in large bodies of water such as
lakes or
25 oceans; these include platform and jack up rigs, drilling ships as well as
other ships.
Personnel normally work and live on these offshore units for predetermined
periods of
time, but must be evacuated from time to time due to extreme emergency
conditions
such as violent weather. The present submarine evacuation system comprises one
or
more underwater modules that are attached to or built into the offshore unit
such that
30 they are not adversely affected by the water surface conditions. Each
module includes
a submarine that is launched with a contingent of personnel from the offshore
unit.
The submarine would also be launched during maintenance checks and drills.
Though the prime purpose of the submarine evacuation system is to evacuate
personnel in emergency situations, the submarines may also be used to ferry
35 personnel and cargo to and from the offshore units.
CA 02439844 2003-09-05
The semi submersible drilling rig 1, illustrated in figure 1, includes a pair
of
pontoons 11 with a number of vertical columns 12 that support an upper hull
13.
Some of the columns 12 may be partially hollow to allow passage from the upper
hull
13 to the pontoons 11. The hull 13 includes the accommodation area 14 with a
5 helideck as well as the drilling floor, equipment and tower 15. The rigidity
of the
structure is achieved by transverse braces 16 between the columns 12 and other
braces
17 between the columns 12 and the hull 13. The pontoons 11 include ballast
tanks 18
that are flooded with water to submerge the drilling rig 1 to a predetermined
depth for
stability. The rig 1 may have its own propulsion system 19 for moving it from
one
to location to another, however the rig 1 would normally be towed by tugs if
it were to
be moved any great distance. While in position for drilling, the rig 1 could
be held in
place by anchors or could be dynamically positioned through the use of
thrusters.
The submarine evacuation module 20 in accordance with the present
invention, as seen in figures 2 and 3, comprises an enclosed bay 22 in the
shape of a
large tube for receiving a submarine type of self propelled underwater vehicle
21; the
bay 22 is mounted within or on an offshore unit as will be described below.
The
submarine 2lis cradled within the bay 22 by a roller system 23 comprising five
sets of
rollers 231 to 235 positioned longitudinally along the bay. Three sets of
rollers 231 to
233 support the bottom and the lower sides of the submarine 21 while the
remaining
sets of rollers 234 and 235 are positioned to contact the submarine 22 on its
upper
sides. In addition, the submarine evacuation system 20 includes a hold fast
hook 24,
which couples to a U-bolt 26 to hold the submarine 21 in place. The bay 22
further
includes a hydraulic control system 27, which is used to control the flooding
of the
bay 22 via the sea chest valve 28, to control the opening of the bay door 29
via a valve
295 and the deflooding of the bay via the sump 30. At the top of the submarine
is
located universal mating system (UMS) hatch 25, which connects to a tubing 31
to
permit entry into the submarine 21. Details of these bay 22 components will be
described below.
As described above, in operation, the pontoons 11 and a portion of the
columns 12 of a semi submersible rig 1 are normally submerged in the water.
The
submarine evacuation module 20 is therefore positioned below the water line.
As
shown in figure 4, for a retro refit, the submarine evacuation module 20 is
positioned
just above the pontoon 11 beside a column 12 allowing access to the submarine
evacuation module 20 via a watertight utility shaft 40. The utility shaft 40
can include
CA 02439844 2003-09-05
6
a stairwell 41 as well as a pair of evacuation poles 42 leading from the upper
deck 131
of the upper hull 13 as well as from the lower deck 132.
In a further embodiment of a retro fit system, the submarine evacuation
module may be located well above the water level such as on lower deck 132. In
such
an embodiment, a chute would be provided to enable the submarine 21 to enter
the
water. During drills and the like, the submarine 21 would have to be lifted
back into
position using a crane.
to As shown in figure 5, for a newly constructed semi submersible rig 1,
submarine evacuation modules 20 may occupy the space normally used for ballast
tanks and the utility shafts 40 descend to the top of the pontoon 11. In this
embodiment, the space around the tube bay 22 can still be used for ballast, as
can the
space within the tube bay 22 after the submarine 21 has departed.
Figure 6 is a top view of the pontoons 11 showing possible locations for the
submarine evacuation modules 20 either over or within the pontoons 11. In the
embodiment where the submarine evacuation modules 20 are within the pontoons
11,
the bay doors 29 are positioned against the hull of the pontoon 11.
In the above embodiments described with respect to figures 5 and 6, the
submarine evacuation systems 20 are shown to be positioned next to the columns
12
and utility shafts are provided for the personnel to descend to the submarine
module
20, however, the columns 12, which are normally hollow can be used to provide
access form the upper and lower decks 131, 132 to the upper surface of the
pontoon
11.
As shown in the schematic drawing in figure 7, the submarine evacuation
modules 20 may also be mounted within a vessel such as a drilling ship 70 or
other
3o vessel, either below or above the water level. Ship 70 is divided into
watertight
compartments 71 by bulkheads 72. A submarine evacuation module 20 may be
located in one or more of the compartments 71 on both sides of the vessel 70.
The submarine bay 22 may be of any appropriate shape to receive the
submarine 21. As shown in figures 2 and 3, for an elongated generally
cylindrically
shaped submarine 21, the bay 22 would have a tubular shaped body 221 that is
closed
CA 02439844 2003-09-05
7
off at one end by a wall 222 and other the other end by the bay door system
29. The
tubular body 221 may be circular, oblong, square or rectangular in cross-
section.
Marinel, an ultra high strength cupronickel alloy, KOS00 is an appropriate
material for
the construction of the bay 22. Tubes, suitable for this purpose, are
manufactured by
S Metals Unlimited (www.metalsunlimited.com).
The submarine 21, such as an Odyssey manufactured by ISE Ltd.
(www.ise.bc.ca), is fitted with seating 210 to carry personnel from the rig 1.
As with
all submarines, the submarine 21 includes a ballast tank 211 and ballast tank
valves
to 212 to control its ascent and descent in the water. It also includes air
tanks 213 and
vents 214. The submarine propulsion system includes an electric motor 21 S
driven by
batteries housed in a seamless, stainless steel battery storage area 216 and a
diesel
motor (not shown). The diesel motor is used to drive the submarine as well as
to
recharge the batteries, and may be operated while the submarine 21 is on the
surface
1 S of the water or submerged. The submarine 21 includes a UMS hatch 2S for
entry into
the submarine 21 and may further include remote controls 217 for controlling
the
flood valve 28, the hook 24 and the door 29. The submarine 21 would normally
also
have its own sonar system for underwater navigation.
2o Though it is desirable to have the bay 22 totally empty of water while the
submarine 21 is in the bay 22 and not in use, it may occur that it is
necessary to have
the bay 22 flooded, and therefore in order to be able to load the submarine
21, a
flexible tube 31 is necessary. The flexible tube 31 is positioned between the
hatch
221 on the bay 22 and the UMS hatch 2S to allow the movement of personnel from
25 above the tube 22 wall into the submarine 2. The tube 31 is permanently
sealed to the
hatch 221 by a compressible pipe connector 222 at the bay 22 and is detachably
sealed to the UMS hatch 2S at the submarine 21 by an expandable pipe connector
250,
which presses up against the cowling 2S 1 on the UMS hatch 25. The expandable
pipe
connector 2S0 is designed to release after the hatch 25 has been closed and
sealed.
3o The bay hatch 312 prevents water from entering into the space above the bay
22 from
within the tube 31 when it is detached from the submarine 21. The tube 310 may
be
made of any type of material that will allow it to withstand the pressure of
the
surrounding water, however it is preferred to be made out of a flexible
material such
as rubber or Teflon~. In addition, an activation button 313 is located within
the UMS
35 hatch 2S, which starts the launch sequence once the last person has entered
the
submarine 21. The activation button 313 is located in the dogged seal of the
hatch 2S
CA 02439844 2003-09-05
such that it is activated when the hatch 25 is closed.
A similar flexible tube 32 with compressible pipe connectors may be used to
permanently seal a tunnel between the bay 22 hatch 221 and the utility shaft
40 as
shown on figure 5, to keep the ballast water in the pontoon 11 from entering
the utility
shaft 40 or the bay 22.
A watertight door system 29 of the type illustrated in figures 9a to 9c is
used
to isolate the submarine bay 22 from the water outside of the offshore unit 1.
Though
1o this door system 29 is shown as being of the sliding door type, a swinging
door type
of system could also be used. The door system 29 may be of the Jefferson type
manufactured by USA Sliding Doors, Inc. (www.usaslidingdoors.com). The
watertight door system 29 includes a door 290 that slides within a frame 291.
The
system 29 is installed as a unit by welding the frame to the hull 299 of the
pontoon 11
or other vessel. Hydraulic cylinders 292, under pressure hold the door closed
within
the frame 291. In addition, springs 294 are positioned within the frame 291,
under
compression, to push against the door 290 to open it as the pressure in the
cylinders
292 is released. It is preferred that the sliding door system 29 be made of
the same
material as the offshore unit hull 299, as this will prevent the generation of
electrical
2o currents between dissimilar metals in salt water. For example, if the
offshore unit hull
299 is manufactured from H 30 Steel, then the door system 29 will be made from
the
same grade of steel. A sonar system 296 transmitting and receiving unit would
also
be attached to the hull 299 just outside of the door system 29 in order to
detect any
obstructions that could prevent the submarine 21 from leaving the submarine
bay 22.
To assure that the bay 22 is water tight, a seal 294 is placed along the outer
edge of the bay 22 wall and the inner wall of the hull 299 as illustrated in
figures l0a
and l Ob. These same seals 294 will also make the door watertight.
3o The release hook system 24 that is used to prevent forward and aft motion
of
the submarine 21 while it is cradled in the bay 22 may be a Z series quick
release
hook manufactured by Zlada Technology (wvv.zaldatechnolog. .~) as shown in
side view in figure 1 la and in top view in figure 1 lb. Hook system 24
includes a base
240 which may be bolted or preferably welded to the bay 22 wall. The frame 241
of
the hook system 24 is pivotally mounted to the base 240 to permit it to move
in a
horizontal plane. A hook 242 is latched within the frame 241 such that it is
held in a
CA 02439844 2003-09-05
9
closed position. A manual releaselsafety lock can be actuated by arm 243 to
release
the hook 242. In addition, the hook 24 may be actuated remotely by electric,
pneumatic or hydraulic controls. The hook 24 may also monitor the load on the
hook
242 for display.
As illustrated in figure 12, the submarine 21 is firmly coupled to the hook
system 24 by a U-bolt 26. U-bolt 26 is fixed to the submarine 21 such that, as
the
submarine 21 backs into the bay 22, the U-bolt 26 passes over the hook 242,
which is
forced upward to latch onto the U-bolt 26 resulting in a snug fit which
prevents the
1o submarine 21 from moving forward or aft. For strength and durability, the U-
bolt 26
may be a grade 8, 1541 stretch proof stainless steel finished with mechanical
galvanizing.
Each of the roller systems 231 to 235 consists of a series of three-foot chain
roller sections; a front view of one roller section 236 is shown in figure 13.
Each
section 236 is welded to a steel channel 237, which is welded to the interior
of the bay
22 at locations shown in figures 2 and 3 resulting in a five contact points on
the
outside of the submarine 21. Each roller system 231 to 235 includes three foot
roller
sections 236 placed end to end as close as possible. The roller system 231 to
235
2o cradles the submarine 21 and acts as a guide for the launch and the re-
entry of the
submarine 21. It also prevents any lateral movement of the submarine 1 while
in the
sub bay 22. The roller sections 236 may be the ERF Series Chain Action Steel
Roller
System having a 120 Ton capacity, manufactured by Hilman Rollers
(~~r~~,r~~J.hilman~~ollers.corn).
Each submarine evacuation module 20 has its own control system 27 to
operate the loading and launching of the submarine 21. As illustrated in
figure 14, the
present embodiment includes a hydraulic control system 27 having a hydraulic
reservoir 271 and a hydraulic pump 272. Appropriate hydraulic units are
3o manufactured by Prohold Workholding, Inc. (www.prohold.com). The control
system
27, which is operated by an activation button 313, controls the sea chest bay
flooding
valve 28, the door opening valve 295 and the hook 242 release valve 245. With
the
activation of the sea chest bay flooding valve 28, which is a pressure-
released valve,
the bay 22 is flooded. After a predetermined time delay, when flooding is
complete,
there will be equal pressure on the inside and the outside of the door 29,
which
facilitates its operation. In addition, the control system 27 receives sonar
information
CA 02439844 2003-09-05
from the sonar system 296 to determine whether obstacles exist that would
prevent
the submarine from being launched. However, a manual override control center
217
is located within a hatch in the stern of the submarine 21. As seen in figure
15, the
manual overnde control center 217 includes a deactivate button 313a to stop
the
launch process at any phase if required. In addition, the manual overnde
control
center 217 includes a flooding/deflooding valve 2$a and a door open valve
295a, as
well as a point where the bars that hold the U-bolt 26 in place can be sheared
to
release the U-bolt 26. The hatch can then be sealed water tight to launch the
submarine 21. The manual override control center 217 may be operated
1o mechanically, hydraulically, or electrically including wireless control.
Thus, the control system 27 and the manual override control center 217 in
each module 20 are basically utilized to flood the submarine bay 22, open the
bay
door 29, release the hook 242 to allow the submarine 21 to motor out of the
bay 22 to
safety. This process is reversed for re-entry of the submarine 21 into the bay
22
where it is guided by the roller systems 231 to 235 into place, the submarine
21 is
coupled to the hook 242, the bay door 29 is closed, the bay 22 is deflooded by
the
sump 30.
2o For the safe operation of the submarine evacuation modules 20, particularly
at
times of critical emergency when the personnel must leave the offshore unit l,
a
trained Coxswain and Assistant Coxswain would be placed in charge of each
submarine evacuation modules 20. The Coxswain is responsible for the piloting
and
operation of the submarine 21, while the Assistant is responsible for the
personnel that
are to be evacuated, for the launch sequence, and to take over from the
Coxswain if
helshe is unable to fulfill hisJher duties.
The process for evacuating the personnel assigned to a particular submarine
evacuation module 20 from an offshore unit l, in an emergency, is illustrated
in
3o figures 16a and 16b. Though a specific process is described herein, it is
evident that
certain non-critical steps may be omitted or others inserted, depending on the
circumstances of the evacuation. The process includes:
Step A - Under the orders of the offshore unit 1 Captain, a general evacuation
alarm is
sounded on the offshore unit 1.
Step B - The personnel retrieve their survival suits and proceed to their
assigned first
CA 02439844 2003-09-05
11
muster station 161, (see figures 4 and 5). The first muster station 161 would
normally be located on the lower deck 132 near the utility shaft 40.
Step C - The Assistant Coxswain does a head count at the first muster station
161.
Step D - The personnel are directed to proceed down the utility shaft 40 to
the second
muster station 162. The second muster station 162 is located at the bottom of
the utility shaft 40 at the UMS hatch 312 to the submarine bay 22.
Step E - The Coxswain does a second head count at the second muster station.
Step F - The Coxswain enters the submarine 21 to ensure that the submarine
evacuation module 20 is in the ready mode, to do a precheck of all gauges,
1 o navigational equipment and fuel and to initiate engine and system start.
Step G - Final instructions from the Captain of the offshore unit 1 are given
to
evacuate the unit 1 immediately or to remain on board. Personnel will remain
at the second muster 162 station until such an order is given. The Coxswain
confirms receiving the order and confirms that all personnel are present or
accounted for. If the order is to abort the evacuation, the personnel return
to
their work stations.
Step H - If the order is to evacuate the unit 1, the personnel proceed to
enter the
submarine 21 and take their seats.
Step I - The Coxswain does a final head count.
2o Step J - The Assistant Coxswain is the last to enter the submarine 21
through the
IIMS 31 and presses the activate button for initiating the submarine launch
control system 27.
Step K - If the submarine launch control system is initiated, the Assistant
Coxswain
closes the hatch 311 and verifies that it is properly sealed. If the hatch is
not
properly sealed, the Coxswain presses the stop button 313a to stop the
submarine launch control system 27 so that the hatch 311 may be opened and
reelosed after the submarine launch control system 27 is reinitiated.
Step L - The bay 22 is flooded under the control of the submarine launch
control
system 27.
3o Step M- The bay door 29 is opened under the control of the submarine launch
control
system 27.
Step N - The submarine evacuation module sonar 296 attached to the hull 299
verifies
that there is no obstruction at the entrance to the bay 22 that would prevent
the
submarine 21 from being launched.
Step O - The hook 242 is released to free the submarine 21.
Step P - The submarine 21 is motored out of the bay 22 into the open water
where it
CA 02439844 2003-09-05
12
can continue to a rendezvous point or to shore either under the water surface
if
conditions warrant or on the surface using its diesel engine.
In the situation where the submarine launch control system 27 should fail
after
it is activated in step J, the following steps are taken:
Step KK- The Assistant Coxswain closes the hatch 311 and verifies that it is
properly
sealed.
Step LL- The bay 22 is flooded under the control of the manual override
control
to center 217.
Step MM- The bay door 29 is opened under the control of the manual overnde
control
center 217.
Step NN- The submarine evacuation module sonar 296 attached to the hull 299
verifies that there is no obstruction at the entrance to the bay 22 that would
prevent the submarine 21 from being launched.
Step 00- The U-bolt 26 is sheared to free the submarine 21.
Step P - The submarine 21 is motored out of the bay 22 into the open water
where it
can continue to a rendezvous point or to shore either under the water surface
if
conditions warrant or on the surface using its diesel engine.
For this type of evacuation system, periodic maintenance, education and
training must be implemented on a regular basis. Drills must be conducted on a
continuous basis such as the ones that are in place for current evacuation
procedures.
It is also desirable to conduct these drills during rough weather in order to
properly
prepare all personnel.
The submarine evacuation system in accordance with the present invention
provides underwater evacuation modules for launching submarine vehicles from
any
type of vessel or fixed structures in large bodies of water, such as oceans.
The benefit
of this system being that violent weather conditions existing above the water
level can
be avoided in the event of an emergency evacuation.
While the invention has been described according to what is presently
considered to be the most practical and preferred embodiments, it must be
understood
that the invention is not limited to the disclosed embodiments. Those
ordinarily
skilled in the art will understand that various modifications and equivalent
structures
CA 02439844 2003-09-05
13
and functions may be made without departing from the spirit and scope of the
invention as defined in the claims. Therefore, the invention as defined in the
claims
must be accorded the broadest possible interpretation so as to encompass all
such
modifications and equivalent structures and functions.
