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SITE) TARGET SSRNM (SU..(U) NAVAL FACILITIES
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PROJECT DOCUMENTATION REPORT
FORACS TARGET
SSRNM ARRAY INSTALLATION
AUTEC/St. Croix
November 1984
FPO-1-84(31)
Prepared by:
Lawrence Mendlow
-. 
Bruce Schuckman
Sandra Vickstrom
Approved:
D. A. Raecke, Director 
E. B. 
n cer,.Tech~nical Director
construction Division 
Ocean Engineering and Construction
Project Office
Ii.c
\ 
1tpub 
Tel
DiMti.i~ 
_____
Unclassified
SECURITY CLASSIFICATION OF THIS PAGE 
......
REPORT DOCUMENTATION PAGE
la. 
REPORT SECURITY CLASSIFICATION 
lb. RESTRICTIVE MARKINGS
Unclassified
2a. SECURITY CLASSIFICATION AUTHORITY 
3. DISTRIBUTION AVAILABILITY OF RE
Approved for public release;
distribution is unlimited
* 
2b. DECLASSIFICATION/DOWNGRADING SCHEDULE
4. PERFORMING ORGANIZATION REPORT NUMBER 
5. MONITORING ORGANIZATION REPORT
"9' 
FPO-i-84(31)
6a. NAME OF PERFORM. ORG. 6b. OFFICE SYM 
7a. NAME OF MONITORING ORGANIZATIO
Ocean Engineering
& Construction
Project Office
CHE SNAVFACENGCOM
6c. ADDRESS (City. State, and Zip Code) 
7b. ADDRESS (City, State, and Zip
BLDG. 212, Washington Navy Yard
Washington, D.C. 
20374-2121
8a. NAME OF FUNDING ORG. 8b. OFFICE SYM 
9. PROCUREMENT INSTRUMENT INDENT
8c. ADDRESS (City. State & Zip) 
10. SOURCE OF FUNDING NUMBERS
PROGRAM 
PROJECT TASK WORK Ulf
ELEMENT # 
* 
* 
ACCESS '
11. TITLE (Including Security Classification)
FORACS Target SSRNM Array Installation AUTEC/St. Croix: 
Project Documentatil
Report
12. PERSONAL AUTHOR(S)
Lawrence Mendlow. Bruce Schuckman & Sandra Vickstrom
13a. TYPE OF REPORT 
13b. TIME COVERED 
14. DATE OF REP. (YYMMDD) 15. PAE
FROM 
TO 
84-11 
18
16. SUPPLEMENTARY NOTATION
17. 
COSATI CODES 
18. SUBJECT TERMS (Continue on reverse if ne(
FIELD 
GROUP 
SUB-GROUP 
FORACS. Arrays. Atlantic Undersea Test ar
____-__ 
__Evaluation 
Center. St. Croix
19. ABSTRACT (Continue on reverse if necessary & identify by block number)
NOSC Code 6362 tasked CHESDIV FPO-1 to install two FORACS Targets at AUTEC.
Andros Island, Bahamas and one FORACS Target and c.e SSRNM Array at the
Underwater Tracking Range. St. Croix. USVI.
20. DISTRIBUTION/AVAILABILITY OF ABSTRACT 
21. ABSTRACT SECURITY CLASSIFICATI
SAME AS RPT.
22a. NAME OF RESPONSIBLE INDIVIDUAL 
22b. TELEPHONE 
22c. OFFICE SYMB(
Jacqueline B. Riley 
202-433-3881
DD FORM 1473, 84MAR 
SECURITY CLASSIFICATION OF THIS PA
++i 
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.
.
J .
-
.
+ Jr 
-
.
.
*** 
*,. 
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.
" CTABLE 
OF CONTENTS
* 
List of Tables 
iii
List of Figures
List of Acronyms 
iv
-' 
1.0 Management Summary 
1
1.1 Background 
I
1.2 System Description - FORACS 
1
1.3 System Description - SSRNM 
3
1.4 Construction Site - AUTEC 
3
1.5 Construction Site - St. Croix 
3
1.6 Construction Planning Summary 
5
1.7 Construction Operations Summary 
5
2.0 Location Details 
7
2.1 Geographical Data, Site Plan, and System Element
Locations 
7
3.0 Installation Details 
7
3.1 Installation Details/Comparison with Specifications 
7
4.0 Recommendations for Future SSRNM Installations 
11
Accesion For
NTIS 
CRA&I
OTIC 
TAB 
03
Unannounced 
1
justification ... 
.. 
......
By ...... 
. ......
Dist. ibuton
Availability Codes
Avail and I r
Dist 
Special
[A -,
LIST OF TABLES
2.1 AUTEC Installed Locations 
8
-
2.2 St. Croix Installed Locations 
10
LIST OF FIGURES
1.1 FORACS Target 
2
1.2 SSRNM Array 
4
.
2.1 AUTEC Installations 
9
2.2 St. Croix Installations 
11
3.1 SSRNM Termination Device 
13
• 
, 
,WO
1 
i
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LIST OF ACRONYMS
d 
CHESDIV 
Chesapeake Division, Naval Facilities
,- 
-
Engineering Command.
" 
NOSC 
Naval Ocean Systems Center.
UCT-1 
Underwater Construction Team One.
APL 
Applied Physics Laboratory, University
of Washington.
.
AUTEC 
Atlantic Underwater Test and Evaluation
Center.
AFWTF 
Atlantic Fleet Weapons Training
Facility.
UTR 
St. Croix Underwater Tracking Range.
DTNSRDC 
David W. Taylor Naval Ship Research and
Development Center.
SUPSALV 
Supervisor of Salvage, Naval Sea
Systems Command.
BIW 
Boston Insulated Wire Company.
FORACS 
Fleet Operational Readiness Accuracy
.
J-. 
Check Site.
SSRNM 
Surface Ship Radiated Noise Measurement.
V
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1.0 MANAGEMENT SUMMARY
I 
1.1 Background
NOSC Code 6362 tasked CHESDIV FPO-1 to install two FORACS
-. 
Targets at AUTEC, Andros Island, Bahamas and one FORACS Target and
one SSRNM Array at the Underwater Tracking Range, St. Croix, USVI.
The organizations that participated in the project were:
1) NOSC - Funding, SSRNM Equipment and ET's.
S.-2) 
CHESDIV - Installation Planning, Installation Coordination,
"' 
SEACON.
3) UCT-1 - Deckforce, Installation Planning.
.4) 
APL - FORACS Equipment and Engineers, FORACS Targets
Positions.
5) AUTEC - On-site Logistics.
6) AFWTF - On-site Logistics.
NOSC funded the project through the following documents:
N66001 83WR 00412 
$30,000.00 
23 JUN 1983
, 
N66001 83RC 00097 
$100,000.00 
10 AUG 1983
N66001 84WR 00086 
$10,000.00 
4 NOV 1983
N66001 84WR 00214 
$137,000.00 
19 JAN 1984
, 
.
N66001 84RC 00053 
$78,000.00 
8 FEB 1984
N66001 84WR 00391 
$45,000.00 
23 APR 1984
N66001 84WR 00491(Amend 1) 
$4.000.00 
22 MAY 1984
N66001 84RC 00094 
$32,000.00 
22 MAY 1984
1.2 System Description - FORACS
FORACS ranges consist of a series of radar and acoustic targets
used to check the accuracy of a ship's sensors. 
CHESDIV was tasked
to install several acoustic targets (a deep and shallow water target
at AUTEC and a deep water target at St.Croix with a backup to be
installed as a shallow water target at St.Croix if time permitted).
" 
See Figure 1.1 for a typical FORACS acoustic target.
Each target is separately cabled back to shore (with Simplex
.057/.180 Quad Cable) and into a control panel located in the
control room of the appropriate facility. CHESDIV efforts consisted
- iof 
bringing the cable to the on-shore termination boxes. 
The
connections to the termination boxes and the cabling and connections
between the boxes and the control panel were carried out by the
facility and APL.
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Figure 1.1
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The targets were designed and built by APL. The target
locations were selected by APL after consultation with the
respective facilities. The position was not considered critical so
there was no specification of accuracy in the X-Y plane.
However, depth was considered important and specifications for
depth were given; for the shallow targets the depth was permitted to
vary from the selected depth to 10 ft deeper than the selected
depth. For the deep targets the depth was to be between 1200 and
t- 
1300 feet. 
However this was permitted to be varied on site with the
consent of the APL engineer on board.
1.3 System Description - SSRNM
The SSRNM system is a vertical acoustic array designed to
analyze the acoustic signature of a surface ship. The SSRNM array
consists of a subsurface float, a Kevlar strength member, electrical
cables and four hydrophones. 
The array was also designed to have a
powered pinger on it for 3-D location on the range. 
The array is
held in position by a concrete clump (17.000 lbs in air, 9,600 lbs
S 
in water). 
A specially designed cable connects the array to shore,
with transformers in a junction chamber at the base of the array to
insure proper signal strength/impedance. On shore is an electronics
van where all the signal processing occurs. 
See Figure 1.2 for
SSRNM Array.
The array was designed and built by NOSC in conjunction with
0 
DTNSRDC. The location was provided by NOSC and the UTR. Once again
vertical control was considered more important than horizontal
control. 
Horizontally, a several hundred foot error was considered
r 
acceptable, but vertically, the top of the buoy had to be between a
depth of 100 ft and 120 ft, based on the draft of large tankers and
diver limitations.
1.4 Construction Site - AUTEC
AUTEC is located on Andros Island, Bahamas. 
It consists of an
acoustic range, a weapon range and a FORACS range with all the
support facilities to maintain the base, the ranges and all the
equipment that the ranges use. 
The cable landing site was inside a
--.
'- 
[ 
cut in the reef permitting SEACON to approach no closer than 1 mile
from shore and necessitated use of an AUTEC LCM-6 to pull the cable
to shore. An existing cable trench was used to route the cable from
the beach to the Command and Control building.
- -1.5 
Construction Site -
St. Croix
The St.Croix UTR under the cognizance of AFWTF, Roosevelt Roads,
PR is located at Sprat Hall, 1 mile north of Frederiksted, ST.Croix,
USVI.
3
IviELDFD 
~bOLTED
UCY
NET eUOYANCY 
4170 LBS
HYDROPHONE 
-2
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K_____2631 FT.
Ii 
HYDROPHONE 
=3
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HYDROPHONE 
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SECUR7D 
1-0 
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PLP STOPPER 
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SSRNM ARRAY
Figure 
1.2
4
m 
v
The facility overlooks the beach landing site on a steep 30 ft
high bluff. 
The shore drops off fairly quickly, permitting SEACON
to approach within 1200 ft of the shore.
1.6 Construction Planning Summary
S: 
23 Jun 83 
Original tasking for FORACS/SSRNM
Installation.
17 Nov 83 
Dates of Installation and use of SEACON
finalized.
19 Jan 84 
Op order 2-84 promulgated.
20 Mar 84 
Project Execution Plan - FPO-1-84(l)
promulgated.
20 May 84 
Addendum to PEP promulgated.
22 May 84 
Op order 3-84 promulgated.
1.7 Construction Operations Summary
13-18 Feb 1984 
SEACON towed from Norfolk, VA to Fort
Lauderdale. FL.
19-30 Mar 
SEACON and project mobilization at Fort
Lauderdale. FL. 
The effort included
the assembly of the FORACS structures.
the winding of the electrical cables
and the Kevlar rope onto Pengo reels.
and loading the SSRNM cable in SEACON's
cable tank.
31 Mar -
1 Apr 
SEACON transited to AUTEC.
2 Apr 
CHESDIV personnel setup Miniranger
shore stations. 
UCT-1 and AUTEC
personnel set up the beach site for
hauling the cable ashore.
3-4 Apr 
Installed deep water FORACS Target.
5-6 Apr 
Installed shallow water FORACS Target.
7 Apr 
UCT-1 and CHESDIV personnel pulled the
near shore portion of the cables into
position and demobilized the shore
sites. 
SEACON departed AUTEC.
8-13 Apr 
The USS PAPAGO. ATF 160, towed SEACON
to NAVSTA Roosevelt Roads. PR.
5
13-14 Apr 
Picked up the SSRNM clump and the
FORACS cable for St.Croix Operations at
NAVSTA Roosevelt Roads. 
Wound the
FORACS cable on Pengo reel.
15 Apr 
SEACON transited to St.Croix.
16 Apr 
UCT-1 and CHESDIV personnel set up the
shore site.
17 Apr 
Plumbed the SSRNM site and cut the
SSRNM Kevlar strength member to match
the depth at the installation site.
-NOSC 
personnel installed a new socket
on the Kevlar strength member.
18 Apr 
Installed deep & shallow FORACS Targets.
19 Apr 
Equipment failure caused loss of SSRNM
clump/shore cable/junction chambers.
29 Apr 
With SUPSALV personnel using Deep Drone
aboard USNS MOHAWK, T-ATF 170, the
clump was recovered aboard SEACON.
30 Apr 
Recovered the shore cable into the
SEACON's cable tank.
I May 
UCT-1 and CHESDIV personnel broke down
the shore site. 
SEACON transited to
NAVSTA Roosevelt Roads.
14-18 May 
BIW reterminated the SSRNM cable on
board SEACON.
23-25 May 
SEACON mobilized at NAVSTA Roosevelt
SRoads.
25-26 May 
SEACON transited to St.Croix.
26 May 
Set up the shore site.
27-28 May 
Installed the SSRNM array.
28 Ma, 
Demobilized the shore site.
28-29 May 
SEACON transited to NAVSTA Roosevelt
Roads, PR.
30 May 
Demobilized SEACON
6
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'S 
T
2.0 LOCATION DETAILS
2.1 Geographical Data, Site Plan & System Element Locations
AUTEC is located at Andros Island Bahamas. 
The FORACS Range
uses a local grid with the North Tower as the origin and the Y axis
*:. 
at an azimuth of 305.90. 
CHESDIV chose to use a grid system based
on true north and selected on old AUTEC construction grid. 
In this
system the location of the North Tower is (11430 X. 47625 Y). 
To
convert from the FORACS grid to this grid system use the following
formulas:
Xcg = Xf Cos(305.9) - Yf Sin(305.9) + 11430
Ycg = Xf Sin(305.9) + Yf Cos(305.9) + 47625
To convert from the construction grid to the FORACS grid use the
following formulas:
Xf = (Xcg -
11430) Cos(305.9) + (Ycg - 47625) Sin(305.9)
Yf = (Xcg -
11430) Sin(305.9) + (Ycg - 47625) Cos(305.9)
The conversion from latitude/longitude to FORACS grid is done by the
range. 
The North Tower and the Instrument Tower were used as
miniranger transponder stations. The location of the miniranger
stations and installed targets are shown in Table 2.1 and Figure 2.1.
The St.Croix Underwater Tracking Range is located on the west
side of St.Croix, north of Frederiksted. The range uses a local
grid based on a rotation and translation of UTM coordinates. 
This
was the system used for this project. Conversion between
latitude/longitude and the grid system is accomplished by the
range. 
Sprat Hall and the Coast Guard Light at the foot of
IL 
Frederiksted Pier were used as miniranger shore transponder sites.
The locations of the miniranger sites, the FORACS targets and the
SSRNM array system are shown in Table 2.2 and Figure 2.2.
3.0 
.STALLATION DETAILS
3.1 Installation Details/Comparison with Specifications
The FORACS target was a package provided by APL and installation
went as planned. 
No changes in the design were required. However,
there was a break in the cable during the installation of the
shallow FORACS target at AUTEC. The splice to reconnect the cable
* 
is in the cable trench well on shore. 
What was learned from this
experience is that the shallow FORACS targets are diver repairable.
. , 
By simply removing the bolts from the chamber flange connection and
disconnecting the underwater mateable connectors, the chamber can be
brought to the surface. All location changes were as a result of
water depth requirements and agreed to by APL. 
A comparison between
the planned and the installed locations is shown in Table 2.1.
7
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19000 
21000
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PRCrjSED 
LOCATION 
DEPTH IN FATHOMS
+INSTALLED 
LOCATION
A17TEC Installations
Figure 2. 1
9
-I,
%._ 
m
PLANNED LOCATION 
INSTALLED LOCATION
SITE 
X (E) 
Y (N) 
X 
Y
SPRAT 
61,998 
37,859 
61,998 
37.859
COAST GUARD LIGHT 
64,850 
28,375 
64,850 
28.375
DEEP FORACS TARGET 
58,302 
28,774 
58,487 
29.521
-
HOLD POINT FOR DEEP LFTS 
60,400 
36,975 
60,610 
36,985
SHALLOW FORACS TARGET 
60.334 
34.225 
60.584 
34.311
HOLD POINT FOR SHALLOW LFTS 
60,400 
36,975 
60,722 
37.290
HOLD POINT FOR SSRNM ARRAY 
60,279 
37,333 
60,623 
37.054
SSRNM ARRAY 
52,986 
35,029 
53,063 
35,023
Note: All coordinates are in feet.
°% 
-'
ST. CROIX INSTALLED LOCATIONS
Table 2.2
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The SSRNM array, see Figure 1.2, was changed from the original
r 
considerations:
A. 
The original design was based on a 3000 ft water depth, the
selected site was only 2700 ft. and required that 300 ft of Kevlar
% 
strength member be cut off and the Keviar reterminated.
B. 
The triangular termination device was modified to hold the
extra electrical array cable (300 ft) and provide a better strain
relief system. 
See Figure 3.1.
btC. 
Due to the break in the Kevlar strength member a splice
between two Kevlar lengths exists about 100 ft above the clump.
D. 
While attempting to install the pinger. the back plate of
the support bracket was lost over the side. 
No spare was available
so the pinger was not installed. 
If needed divers can install a new
pinger, but depth capabilities to 200 ft will be required by the
divers used because the pinger pigtail came up approximately 50 ft
short of the bottom of the buoy and not the 5 ft as planned.
E. 
The double buoy system was welded together as well as bolted.
-VK 
F. 
The location of the SSRNM is off by 77 ft to the east.
G. 
The depth of the top of buoy was measured by diver at
142 ft, 28 ft deeper than measured by the lowering line during the
installation. The obvious answer as to why the depth is different
than when plumbed and measured is due to the location difference.
However this does not explain why the bottom of the buoy measured
122 ft deep during installation and 150 ft deep the next day. 
This
is due to the stretch of the Kevlar whilc supporting the 9.600 lb
weight less the 4,200 lb buoyancy from the float holding up the
, 
array. 
At 1% stretch, this amounts to 26 feet which is close to the
28 ft observed.
4.0 RECOMENDATIONS FOR FUTURE SSRNM INSTALLATIONS
1. All components should be assembled and pressure tested and
electronically tested prior to installation operations. 
The
strength member should be marked for hydrophone locations not just
length indications.
2. 
All components should be designed to take installation loads not
just installed loads.
3. When depth is as critical as the specifications stated, a better
method of placing the array at the desired depth should be
developed. 
This may require a redesign of the array itself, such as
using a two-point spread moor rather than the single point moor that
... .
was installed.
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4. 
For all ocean operations, have spares for everything, especially
I 
small pieces that are being handled over the side of the vessel.
5. 
Mark length of electrical cable (every 100 ft).
6. 
The array electrical cable length should incorporate a given
percentage of slack in order to accommodate a tension free
connection to the mechanical cable.
7. 
Mark length of shore cable (every 1000 ft or .1 NM).
8. 
Reduce in-air weight/size of clump to make installation handling
easier.
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