Document ID: EPA-HQ-OW-2004-0002-0536
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-11-30T05:00Z

Cooling
Water
Intake
Structure
(
CWIS)
Information
Data
Required
Rig
Information
Rig
Name
Discoverer
Spirit
Discoverer
Deep
Seas
Discoverer
Enterprise
Rig
Type
Dynamically
Positioned
Drillship
Total
Installed
Power
Generation
Capacity
52,118
HP
Number
of
Cooling
Water
Intake
Structures
(
CWISs)
4
Brief
description
of
each
CWIS
(
e.
g.,
sea
chest,
simple
pipe)
Sea
Chest
­­
Forward
Area
2.81
Square
Meters
P&
S
Aft
Area
5.37
Square
Meters
P&
S
Rough
dimensions
of
each
CWIS
and
indicate
whether
onboard
CWIS
has
an
existing
flange
Forward
Machinery
Space
2each
1236mm
x
569
mm
Port
&
Starboard
(
Total
4)
No
Flange
Aft
Machinery
Space
2
each
1236mm
x636mm
&
2
each
1036mm
x
536mm
Port
and
Starboard
(
8
Total)
No
Flange
Screen
type
(
e.
g.,
strainer,
wedge
wire)
with
mesh
size
Sea
Chest
Grid
(
44
each
horizontal
30mm
x
6mm
flat
bar),
Duplex
Basket
Strainers
Total
Design
Specifications
for
Daily
Maximum
Water
Intake
Volume
of
each
CWIS
Forward:
12,682,160
gal
(
2000
Cubic
Meters
/
Hour)
Aft:
41,215,200
gal
(
6500
Cubic
Meters
/
Hour)
Total
Daily
Water
Intake
Volume
of
each
CWIS
Forward:
1,810,827
gal
(
6854
Cubic
Meters)
Aft:
11,833,518
gal
(
44,790
Cubic
Meters
Design
Specs
for
Through
Screen
Velocity
of
each
CWIS
(
i.
e.,
Q=
V*
A)
Forward
1421.5
Meters/
Hour
Aft
2423.5
Meters/
Hour
List
of
Purposes
of
Cooling
Water
Intakes
(
e.
g.,
cool
crude
oil,
produced
water,
power
generators,
drill
pipe
brakes)
Thruster
Motors
and
Drives,
Heat
Exchangers
for
Drilling
Equipment,
Rig
Air
Compressors,
HVAC
Systems,
Main
Engines,
and
Misc.
Auxiliary
Equipment.
List
of
Purposes
of
Non­
cooling
Water
Intakes
(
e.
g.,
fire
water,
hotel
loads)
Water
Makers,
Fire
Main,
Ballast,
Drilling
Mud
Pits,

Total
Volume
of
Water
Intake
for
Ballasting,
Duration
of
the
Ballast
intake,
and
the
Through
Screen
Velocity
of
the
Ballast
Intake
103,200
gal
(
3100
Cubic
Meters)
As
needed
while
on
location,
559
Meters/
Hour
Mitigation
Measures
for
reducing
Exotic
Species
Migration
through
Ballast
water
Vessel
carries
most
Ballast
Water
between
locations,
The
vessel
performs
Ballast
Water
Exchange
in
greater
than
1000Meter
Water
Depth.
Mitigation
Measures
for
reducing
Impingement
and
Entrainment
of
Aquatic
Organisms,
as
well
as
Bio­
fouling
Prevention
Measures
Sea
chest
Grids,
duplex
and
simplex
baskets,
cathodic
protection
and
Blume
anti
Fouling
System.

Is
the
Rig
equipped
with
a
Radiator
Cooling
System
for
the
Main
Engines?
No