2. 2
INTRODUCTION (1.0)
This above mentionedtechnical report is part of the
Compulsory and obligatory requirements for the completion
and award of hyperbaric certification in Surface Suppliedair
Diving Course (Class 2 mention A) of Institut Nationalde
Plongee Professionnelle (INPP) of Marseille,France.
It centers basicallyon the metrology, i.e. measurements
and drawings of a rectangular steel structure and a section of
the Warf profile of the INPP harbor.
Metrology is the science of measurement, embracing both
experimental and theoretical determinationat any level of
uncertainty in any science and technology. It is a very broad
field and is sub-dividedinto three (3) parts.
(a) Scientific or FundamentalMetrology
(b) Appliedor industrialMetrology
(c) Legal Metrology
3. 3
THE WORKSITE (1.1)
The project was carried out in the South-eastern part of
the MediteraneanSea, precisely, Institut Nationalde Plongee
Professionnelle (INPP), Marseille,France between the 1st
and
2nd
of August, 2011.
The weather conditionof the area gave a temperature
range of between 24°C to 34°C in the summer period.
The saline sea water has an average temperature of 15°C
with density of 1.03. The reduced wave and tide action allowed
easy and good access to the workstation during the period of
work. The visibilitywas also good, ranging between 2-3 meters
from the object.
EQUIPMENT AND TOOLS (1.2)
Engineering or technologicalreports are aided
fundamentallyby tools, without which it is impossible to carry
out or obtain data and analysisof reports.
In our research, the following toolswere employed:
(a) Measuring tape
(b) Rope
(c) Drawing board
(d) Pencil
4. 4
(e) VariableVolume Diving Suit
(f) KMB 18 and 37 helmets
(g) Control Panel for Divers Communication
(h) Breathing gas i.e. Air e.t.c
SAFETY PROCEDURES (1.3)
The safety rules and regulationswere strictly followed in
accordance with Decree no 90.277 of 28th
March 1990, Decree
of 28th
January 1991, Decree of 28th
March 1991 and Decree of
15th
May 1992.
The divers were safely kitted with variablevolume suits,
KMB 18 and 37 helmets, diving knife, gloves, safety shoes and
fins. The main air supply, emergency air supply, rescue tank and
bail-outtanks were all at an average minimum of 190bars.
The job was carried out under good surveillanceof
supervisors (trainee) and instructors. All the toolsand
equipmentswere well secured to the divers, so there was no
loss of equipment.
The decompression stops for the divers were well
calculatedand monitored using the MT92 AIR STANDARD
TABLES.
5. 5
METHODOLOGY (2.0)
This has to do with the procedures and systems employed in
the course of obtainingdata and analysisfor the compilationof
the report.
DIVING METHOD (2.1)
Air Surface SuppliedMethodwas employed, this refers to
a process using equipmentsupplied with breathing gas using an
umbilicalfrom the surface. This equipmentsand technique are
mainly used in commercial diving due to the high cost and
complexity of owning and operating the equipment.
Surface Supplieddiving equipment usuallyincludes
communicationwith the surface, which addsto the efficiency
of the diver. Breathing gas is suppliedeither from a specialized
air compressor, high-pressure cylinders or both and a back-up
source is alwayspresent in case the primary source fails. The
diver may also wear a cylinder called “bail-out bottle” which
provide gas in emergency.
6. 6
METHOD OF MEASUREMENT(2.2)
Measurements in this report were done using direct
measurements in Metric System, i.e. meters, centimeters and
millimeters.
PROFILE MAKING (2.3)
The profile was establishedthrough collationof data,
plotting of graph, drawing, free-hand sketches illustratingthe
orientationand position of the steel tank and the wharf. All
plotting and drawings are produced to the scale 1:20
SEARCH METHOD (2.4)
The search method employedfor the locationof the steel
structure within the harborfrom point zero was, “the circular
Jack-stay” method. It is a process or method in which the diver
moves round a fixed point using a radialdistance line to guide
him and snag on any object proud of the bottom.
7. 7
RESULTS AND FINDINGS (3.0)
WHARF PROFILE (3.1)
The project focused the inspectionof the part of the wharf
used as harbor for NARVAL, diving boat of INPP, Marseille.
On a general outlook, the wharf is rectangularin shape
(Appendix5), but the project focused on half part of the harbor,
which appears as letter L on the sectional drawing (Appendix1)
It is 2080cm long and 555cm wide, with height of 400cm at
the northern side and 300cm at the southern side. It consist of
12 rectangulargrooves, the 1st
groove from the northern edge
of the harbor extends the entire height of the concrete, i.e.
400cm, and the other grooves display a reductionorder in
height of about 330cm to 200cm, from the north to the south
part of the concrete pier.
There are 25 rectangularhollow structures on the
concrete pier with dimensions25cm length, 22cm depth and
8. 8
28cm width. Two each occupy a space separated by the long
groove. The second hollowstructure from the north-western
side of the pier has a deformation at the top of the hollow. The
deformation is propagated in an oval shape, forming “a cap” on
the small hollow.
STEEL STRUCTURE (3.2)
The rectangular“E-shaped” empty tank, lies on the sea-
bed at a depth of 7meters sea water. The soil profile of an area
of 1 meter around the tank is predominantlyclayishwith little
and sparsely distributed sand and rubbles, with a general
grayish to light brown coloration.
The tank is mostly rusty all-over its body, giving an
imparted reddish-brown color due to the corrosive effect of the
saline sea water.
The tank plunged in the direction of northwest-southeast,
with an angle of about 80° (Appendix4).
The geometry of the tank can be viewed in (Appendix3 and 2)
The tank is rectangularon a general outlook, with its
length aligning in the east-west direction,i.e. parallelto the
side of the platform of the “ANTEDON” harbor.
9. 9
The tank is approximately16 meters from “point zero” at
an angle of 32° to the platform of the “ANTEDON” harbor.
“Point zero” is the corner between the Nigerian harbor
platform and the “ANTEDON” platform. (Appendix5).
The tank is 330cm long, along the east-west, 290cm wide in the
north-south alignment and average thickness of 23cm.
The tank has some structural designs all over its body,
among them are 6 hollowstructures of equal dimension
(almost square in shape) on the surface and at both sides are
cylindricaland circular structures. See Appendix 3 and 2.
10. 10
CONCLUSION
The report focuses on the metrology of part of INPP wharf and
a steel structure. During the implementationof the task, safety
procedures as concerning hyperbaric environment was strictly
obeyed. The project has broadenedour knowledge and scope
on worksite organization(diving operationsplanning,
operationalresponsibilityboth on surface and underwater;
supervision, inspection,navigationand use of tools).
RECOMMENDATION
It is our view that:
The faulted groove (Appendix I ) should be subjected to
repair to avoidfurther damage.
Regular cleaningof the floor of the wharf to prevent
excessive soil and material deposits.
The steel tank (structure) should be cleaned and coated to
avoid corrosion.
And finally,such training should be encouraged to improve
trainee’s confidence on the job.
