Prepared by RESOLVE SALVAGE & FIRE (AMERICAS) 1510 SE 17 th Street Ft. Lauderdale, FL 33316 For Public Works and Government, CANADA Cabot Place, Phase II, 2nd Floor Box 4600 St. John's, NL A1C 5T2 Job#: 160512 Date: 23/09/2016 Rev: 01 By: RSF This document contains proprietary and confidential business information and is not to be Copied or distributed for any purpose other than the use intended in this proposal. MANOLIS L: WRECK ASSESSMENT
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MANOLIS L: WRECK ASSESSMENT...3. 8372/LOCC/CCG/R001, “MANOLIS L”, Further Considerations of Wreck Status, London Offshore Consultants, 13 February 2015 MANOLIS L: WRECK ASSESSMENT
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Prepared by
RESOLVE SALVAGE & FIRE (AMERICAS)
1510 SE 17th Street
Ft. Lauderdale, FL 33316
For
Public Works and Government, CANADA
Cabot Place, Phase II, 2nd Floor Box 4600
St. John's, NL A1C 5T2 Job#: 160512 Date: 23/09/2016
Rev: 01 By: RSF
This document contains proprietary and confidential business information and is not to be Copied or distributed for any purpose other than the use intended in this proposal.
With markers designated as 1S/P placed at a depth of approximately 51 to 52m, 2S/P placed at 55-56m,
and 3S/P at 59m.
A total of 64 markers were placed on the hull. 18 are located on the bottom shell, 22 are on the
starboard sideshell and 20 are on the port side shell. Two markers were not able to be placed at the
lower edge of the frame 98 and frame 72 due to the rock face impeding the ROVs access.
Figure 2-27: FR41/OUTBD LBHD Marker
The markers were placed utilizing a combination of the STARFIX navigation system as well as visually
following/counting the exposed structure beneath the bottom plating. The plate had warped in way of
major structural members which allowed the team to visually match the data that was provided from
the ROV tracking system.
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The following diagrams illustrate the approximate placement of the magnetic markers.
Figure 2-28: Bottom Shell Marker Locations
Figure 2-29: Port Side Marker Locations
Figure 2-30: Starboard Side Marker Locations
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2.4. HULL THICKNESS RESULTS
Concerns have been raised since 2013 regarding the structural integrity of the MANOLIS and the
potential degradation of the steel plating. During the wreck assessment this was addressed by taking
hull thickness measurements in the vicinity of the 68 magnetic marker locations over the bottom and
side shell plating. The instrumentation used was the M5-ROV Cygnus Gauge, which is purpose built to
be outfitted for ROV use.
Figure 2-31: Cygnus Gauge
The apparatus is operated by firmly placing the sensor (red dot) on a piece of plating or other material.
The reading can then be viewed 'real time' on the software package as well as overlaid onto the ROV
video. Prior to use the Cougar was outfitted with a steel scrub brush. Each location was then cleaned to
remove all growth and rust. The Cygnus gauge was calibrated per the manufacturer's instructions and
the software was configured for the anticipated material to be measured. In the case of the MANOLIS
this was assumed to be mild steel.
The Cygnus gauge is advertised to measure within an accuracy of +/- 0.1mm or 0.1% of the material
thickness. Factors that can play a role in reducing this accuracy include growth or corrosion on the
interior side of the plating as well as operator error. It is ideal to place the sensor as squarely as possible
on the plating. If the sensor is resting at even a slight angle the resulting reading can be skewed. The
ROV operators piloting the Cougar had prior experience with the Cygnus gauge and took great care in
minimizing these errors by taking ample time at each location to achieve a proper interface.
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The thickness readings were then compared to the plating called out on the structural drawings of the
MANOLIS. Below is the midship section which gives the thickness information per location on the
side/bottom shell. Unfortunately, midships is the only available section cut on the structural drawing
that calls out the shell plating thickness. For this reason some assumptions were made regarding the
plating at the fore and aft regions on the hull.
Table 2-32: Midship Section Plate Thicknesses
MARKER
Cygnus
Readings
mm
Hull Thickness
from Drawing
mm
Depth
mm Change
1 FR155 3S 12.55 18 -59.5 5.45
2 FR155 2S 15.68 15 -55.2 0.68
3 FR155 1S 9.3 11 -51.8 1.7
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4 FR155 CL 11.7 13 -51.1 1.3
5 FR155 1P 9.55 11 -51.8 1.45
6 FR155 2P 15.75 15 -55.8 0.75
7 FR155 3P 13.8 18 -61.4 4.2
8 FR145 3S 13.5 15 -58.59 1.5
9 FR145 2S 16.8 15 -54.56 1.8
10 FR145 1S 8.9 11 -51.13 2.1
11 FR145 1P 9.65 11 -51.73 1.35
12 FR145 2P 18.05 15 -54.56 3.05
13 FR145 3P 18.75 18 -59.42 0.75
14 FR126 3S 19.35 18 -57.97 1.35
15 FR126 2S 17.2 15 -56.11 2.2
16 FR126 1S 13.35 14 -50.22 0.65
17 FR126 OUTBD.S 11.15 11 -49.9 0.15
18 FR126 INBD.S 11.15 11 -50.5 0.15
19 FR126 INBD.P 12.65 13 -50.5 0.35
20 FR126 OUTBD.P 7.05 11 -50.8 3.95
21 FR126 1P 12.45 14 -52.7 1.55
22 FR126 2P 16.8 15 -55.5 1.8
23 FR126 3P 19.5 18 -59.8 1.5
24 FR98 3S 19.4 18 -57.7 1.4
25 FR98 2S 18.6 15 -55.15 3.6
26 FR98 1S 11.15 14 -51.8 2.85
27 FR98 OUTBD.S 11.35 11 -49.69 0.35
28 FR98 INBD.S 13.2 13 -50.16 0.2
29 FR98 INBD.P 12.05 13 -50.23 0.95
30 FR98 OUTBD.P 10.2 11 -50.53 0.8
31 FR98 1P 11.8 14 -53.98 2.2
32 FR98 2P 13 14 -55.25 1
33 FR98 3P N/A N/A N/A N/A
34 FR72 3S 15 15 -57.58 0
35 FR72 2S 12.3 15 -55.15 2.7
36 FR72 1S 14.45 14 -51.8 0.45
37 FR72 OUTBD.S 11.7 11 -49.88 0.7
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38 FR72 INBD.S 11.25 11 -50.18 0.25
39 FR72 INBD.P 12.35 13 -51.1 0.65
40 FR72 OUTBD.P 11.05 11 -51.13 0.05
41 FR72 1P 14.4 14 -52.1 0.4
42 FR72 2P 12.9 14 -55.66 1.1
43 FR72 3P N/A N/A N/A N/A
44 FR42 3S 15.75 15 -58.52 0.75
45 FR42 2S 12.5 15 -54.94 2.5
46 FR42 1S 11.45 14 -52.44 2.55
47 FR41 OUTBD.S 10.75 11 -50.84 0.25
48 FR41 INBD.S 9.95 11 -50.22 1.05
49 FR41 INBD.P 10.5 11 -51.67 0.5
50 FR41 OUTBD.P 10.05 11 -51.77 0.95
51 FR42 1P 12.85 14 -51.84 1.15
52 FR42 2P 11.4 15 -54.16 3.6
53 FR42 3P 12.5 15 -58.31 2.5
54 FR27 3S 14.95 15 -59.52 0.05
55 FR27 2S 12.05 13 -56.6 0.95
56 FR27 1S 12.65 13 -52.64 0.35
57 FR27 CL 10.7 11 -50.5 0.3
58 FR27 1P 9.7 11 -52.1 1.3
59 FR27 2P 12.6 13 -55.91 0.4
60 FR27 3P 14.9 15 -59.83 0.1
61 FR14 3S 10.5 13 -58.72 2.5
62 FR14 2S 12.05 13 -56.43 0.95
63 FR14 1S 9.7 11 -50.81 1.3
64 FR14 1P 10.85 11 -51.77 0.15
65 FR14 2P 13.15 13 -56.13 0.15
66 FR14 3P 12.85 13 -59.45 0.15
67 Tank 1.0 11.1 11 -50.25 0.1
68 Tank 5.3 11.15 11 -49.91 0.15
69 Tank 5.0 12.25 11 -50.84 1.25
70 Tank 4.2 12.35 11 -50.52 1.35
Table 2-33: Cygnus Gauge Thickness Reading
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Table 2-34: Cygnus Gauge Bottom Shell Locations
The average deviation between the as built plate thickness and the Cygnus measurements is 1.01mm, or
approximately 10% diminution. This is broken down further by specific plate thickness distribution.
11mm Plate: Average deviation = 0.77mm
13mm Plate: Average deviation = 0.74mm
14mm Plate: Average deviation = 1.39mm
15mm Plate: Average deviation = 1.33mm
18mm Plate: Average deviation = 1.25mm
Data points highlighted in red above have been omitted from the average figures as they have
differentials higher than or equal to 3.0mm. These outliers can be attributed to a number of factors:
- Inaccurate assumption based on lack of plate thickness data at other locations on the hull.
- Inaccuracies in depth readings from the ROV along the side of the ship which could also
contribute to assuming the incorrect thickness along the sideshell.
- Operator error
It can be concluded by the data retrieved that the shell plating has not been significantly degraded by
the corrosive effects of the sea. This could be attributed to the water temperature, salinity levels,
oxygen levels, or the continuing presence of anti-fouling paint. In general, much less growth was
observed on the bottom shell as compared to the sides of the casualty. The integrity of the hull/plating
was further confirmed by the ROV survey which found no signs of buckling or global structural failure
that would indicate the breakdown of internal girders or frames.
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3. OIL ASSESSMENT
The second portion of the wreck assessment entailed carrying out a survey of the oil still held inside the
MANOLIS. The objectives included:
- Locating the remaining hydrocarbons
- Estimating, where possible, the quantity of oil
- Extracting samples in order to identify the type of oil
The oil assessment was carried out primarily thru dive operations with assistance from the ROV where
needed.
3.1. OIL LOCATION
Invasive methods were used to determine the location of the oil in MANOLIS. Divers used a
hydraulically driven magnetic drill to tap into the shell plating of tanks and compartments. The drill
points were made at the high side of the tanks; forward and towards the starboard side of the tank. A
total of 31 penetrations were made over the bottom shell and engine room. The following diagrams
illustrate the drill point locations (See drawing 160512-160-4 in Appendix C for more details).
Figure 3-1: Bottom Shell Drill Locations
Figure 3-2: Sideshell Drill Locations (Starboard and Port Side Respectively
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The results of the drilling yielded the following results which are noted as either containing bulk oil,
traces of oil, or no oil found.
Tank Name Oil Presence DO 0.1S Traces found, negligible volume DO 0.2P N/A DO 0.3S Bulk oil found DO 0.5S Bulk oil found HFO 1.0P Bulk oil found HFO 1.1S Traces found, negligible volume HFO 1.2P No oil found HFO 1.3S No oil found HFO 1.4P Traces found, negligible volume HFO 1.5S Bulk oil found HFO 5.0P No oil found HFO 5.1S No oil found HFO 5.2P No oil found HFO 5.3S No oil found HFO 5.4P Traces found, negligible volume HFO 5.5S Bulk oil found LO 2.0C No oil found LO 2.1C N/A open to the sea LO 2.2C N/A open to the sea LO 2.8P Traces found, negligible volume BWT 4.0C N/A open to the sea BWT 4.1S N/A open to the sea BWT 4.2P N/A open to the sea BWT 4.3S Traces found, negligible volume BWT 4.4P No oil found BWT 4.5S No oil found BWT 4.6P Traces found, negligible volume FWT 3.1S Traces found, negligible volume ENGRM Bulk oil found
Table 3-3: Oil Location Summary
The tanks with traces of oil are shown in the diagram below with the lighter hatching, while those with
bulk oil are shown as solid red.
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Figure 3-4: Oil Location Diagram
3.1.1. FUTURE LEAK POTENTIAL
The risk for future leaks from new locations on the MANOLIS is directly related to the structure integrity
of the hull, aside from outside influences such as icebergs. As there is further degradation in the steel,
new cracks and openings will form and allow the hydrocarbons out of containment. From the evidence
gathered during this assessment it does not appear that this is a risk for the immediate future, although
the recent history of the MANOLIS would suggest otherwise. The risk of any significant release of
pollution seems highly unlikely.
The segregation of oil by tank indicates that the interior bulkheads within the bottom shell are still in
good condition and the compartments between FR41 and FR72 appear to be intact. Likewise, the
forward engine room bulkhead does not appear to have been breached.
3.2. OIL QUANTITIES
The tanks listed above which were found to have product were then further surveyed to estimate the
quantity of oil remaining within. This was accomplished using three different methods depending on
the tank’s location in the casualty and the amount of product:
- Tanks and compartments along the bottom shell that were found to have oil in them were
quantified using a custom made probe that the divers inserted into the tank through drill holes.
The probe would detect the oil level which was simultaneously recorded topside. The oil level
and drill location could then be input into a 3D hydrostatic model of the MANOLIS. The model is
oriented with the appropriate trim and heel and the tanks are then filled to the measured level
using the drill location as a reference point.
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- The side shell tanks were quantified using a traditional salvage method whereby smaller holes
are drilled along the height of the tank to physically find the oil/water interface.
- Tanks with traces of oil found in them were quantified through calculation. A small layer of
product is assumed as 'clingage', and this small layer is multiplied over the surface area of the
top of the tank, i.e. bottom shell.
HFO Tank 1.0: This tank was probed at its initial drill point in the forward corner of the compartment.
The level recorded on the probe was 98cm. This was input into GHS which calculated the tank as being
75-80% full with a correlating volume of 60-65 cubic meters.
HFO Tank 5.5: Tank 5.5 was initially drilled at the forward end of the tank with no traces of product.
However, a second hole was also drilled into the aft area of the tank because of the proximity to the
weighted seal. This hole proved to have bulk oil which was probed and found to be 35cm thick.
Because of the conflicting and inexplicable results a third hole was then drilled approximately 8-9 frames
forward of the aft penetration. The mid location also proved to have bulk oil present. The probe was
deployed and a 55cm thick layer of oil was measured. Both reference points and oil levels were input
into GHS. The aft point yielded 20 cubic meters when the 35cm level was carried out over the full length
of the tank. The midpoint produced a similar but slightly larger volume of 23cu.m. This can be
attributed to the transverse locations of the drill points. The midpoint was drilled further outboard at a
higher point where the oil level would be at its thickest.
There are two possibilities for the lack of oil present at the forward end of 5.5. Either blockage has
occurred in the rat holes of the transverse frames, preventing oil from traveling forward, or the tank top
has collapsed somewhere between the mid and forward location. Due to this anomaly the quantity of
the product in tank 5.5 is estimated to be in a range of 10-25 cubic meters.
Engine Room: The engine room space was drilled in two different locations and found to have product
emitting from both points. When ENGRM2 was drilled a mixture of hydrocarbons was found. It
appeared to contain hydraulic fluid, diesel, and lube. At this location the drill bit hit a frame and the
area was subsequently patched with the aforementioned steel box.
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When ENGRM 1 was drilled an air pocket was struck. The air was slowly released by the ROV
intermittently opening the ball valve on the tap location. Once the air had been purged from the area
the probe was inserted and 102mm of product was measured. This correlated to a volume of
approximately 15cu.m. when input into the GHS model.
The following screenshots are from the hydrostatic software, GHS, which was used for this project (GHS
Output can be found in Appendix D).
Figure 3-5: GHS Screenshots
HFO Tank 1.5: Tank 1.5 is located on the starboard sideshell of the engine room. Initially product was
found when it was first drilled so one additional 5/8" hole was made approximately 1/3 of the way from
the inverted tank top. Oil was discovered at this point as well and the opening was capped by screwing
a 5/8" bolt into the hole. No further holes were made, however, as it was decided to halt additional
drilling operations on the sideshell to reduce the risk of release and avoid creating future leak points
that could not be dealt with by the CCG. For the purposes of estimating the quantity of this tank it is
known to be at least 1/3 filled and possibly more. The total capacity of the tank is 28 cubic meters so
the volume is estimated to be between 15 and 25 cubes.
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Figure 3-6: Tank 1.5 Drilling Ops and installed 5/8" bolt
DO Tanks 0.3 and 0.5: Both tanks were drilled and found to have product. However, because of the size
of the tanks it was decided not to drill additional holes. Both tanks are assumed full and estimated to
have 5cu.m. each.
Tanks w/ Trace Amounts of Product (Negligible Volume): Tanks were deemed to have ‘trace amounts’ of
oil, or negligible volume, based on the results of the tapping and sampling procedure. In these tanks
there was oil visible on the drill bitt, ball valve, divers’ gloves, etc during the initial drilling process.
Tanks were further tested for product by inserting a 1.15m threaded rod thru the interface. In these
cases the threaded rod would be retracted with traces of oil on the rod but not over the entire length.
These tanks were also probed and the sensors did not find a significant layer of oil present. The sensors
would read oil once the probe had been retracted into the hottap/ball valve assembly. These results led
to the conclusion that there was indeed oil present in the tanks, however, only small pockets or
‘clingage’ along the bottom shell.
To estimate the volume of these compartments a 4mm layer of oil was used to calculate the remaining
product in the tanks where trace amounts were discovered. The below is the surface area of the
bottom shell for each tank with the 4mm layer applied. In GHS this has been input as 1.0%.
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WBT 4.3: 82sq.m. = approximately 0.5cu.m
WBT 4.6: 85sq.m. = approximately 0.5cu.m
HFO 5.4: 91sq.m. = approximately 0.5cu.m
DO 0.1: 66sq.m. = approximately 0.5cu.m
LO 2.8: 15sq.m. = approximately 0.1cu.m
FW 3.1: 11sq.m. = approximately 0.1cu.m
HFO 1.1: 32sq.m. = approximately 0.25cu.m
HFO 1.4: approximately 0.25cu.m
The results are summarized in the following spreadsheet.
Tank Total Tank Capacity
Cu.M.
Estimated amount: Low to High Range Notes
DO 0.1S 80 0.5 1 2" Hole drilled, traces found, sample taken, probed w/ negligible results DO 0.3S 5.6 5 5 2" Hole drilled, oil found, assumed full due to small tank size DO 0.5S 5 5 5 2" Hole drilled, oil found, assumed full due to small tank size HFO 1.0P 80.5 60 65 98cm sounding at forward high (inboard) corner of the tank. 75-80% filled HFO 1.1S 32.3 0.25 0.5 2" Hole drilled, traces found, sample taken, probed w/ negligible results HFO 1.4P 28.4 0.25 0.5 Traces found HFO 1.5S 28.4 15 25 2" Hole drilled, oil found, 5/8" hole drilled 1.5m lower. HFO 5.4P 96.8 0.5 1 5.4fwd, no oil, 5.4aft traces found, sample taken HFO 5.5S 96.8 10 25 5.5fwd no oil, 5.5aft 35cm sounding, 5.5mid 55cm sounding LO 2.8P 13.7 0.1 0.5 2" Hole drilled, traces found BWT 4.3S 91.1 0.5 1 Traces found BWT 4.6P 97.3 0.5 1 4.6fwd drilled, no oil, 4.6aft drilled, traces found FWT 3.1S 7.8 0.1 0.5 Traces found ENGRM 1 15 20 Eng. Room 2 and 1 drilled, 102cm found, air pocket also present
Total 112.7 151
Table 3-7: Oil Quantity Estimation
Based on the oil assessment performed the total quantity of hydrocarbons found can be estimated to
fall within the range of 115 to 150cu.m.
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Each drilling location was capped following the oil assessment with a yellow dome similar to the red
ones used for marking the hull.
Table 3-8: HFO 5.2 Marker
3.3. OIL SAMPLE RESULTS
Samples taken from the Manolis L (each approximately 200-300mL in volume) were stored onboard the
Maersk Cutter at 4 Degrees Centigrade until transfer to Petroforma Laboratories for further analysis in
St. Johns, Newfoundland. Of the tanks sampled, those where only water was found were kept as
reference to other tanks until the end of the technical assessment. At the completion of onsite
operations, with concurrence from the Canadian Coast Guard representative, those samples which only
contained water were disposed of.
A total of 11 representative samples were provided to Petroforma laboratories for further analysis.
Initially, Density (API & ATSM 4052) and Flash Point testing (ASTM D93) were envisioned to
appropriately type the hydrocarbon samples. However, some challenges arose from water entrainment,
suitable sample volume and hydrocarbon settling which called for the addition of one Saturates
Aromatics Resins Asphaltenes (SARA) analysis and 5 Carbon 30+ Analysis to ensure samples were
appropriately typed. The results of this testing are listed in the below table and further analysis may be
found in the full Petroforma Report in Appendix E.
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Table 3-9: Petroforma Laboratory Analysis Results
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Generally, the tanks with hydrocarbons present can be confirmed as diesel or #6 fuel oil respectively.
N/A in the table above indicates that a particular test was not conducted for a sample. There was one
anomaly of note which occurred in the sample from Tank HFO 5.4 P AFT. Once delivered to the lab for
additional testing and left to settle at 15 degrees C, the sample settled into 3 distinct layers composed of
light hydrocarbons on top, with saltwater below and a layer of heavy hydrocarbons resting on the
bottom of the sample beaker. After 24 hours of settling this layering persisted which is why a SARA
analysis was performed on this sample of oil confirming a mixture of asphaltenes and other heavy
hydrocarbons. Important to note for this particular sample, is that when the sample was collected the
ambient bottom temperature was recorded at 1 degree C. The sample was collected from the very top
of the tank volume as single sample and the hydrocarbons collected were observed as one continuous
sample. The segregation of specific gravity only occurred upon an increase in sample temperature to 15
degrees C. This behavior was not observed in any other samples. As such, this does not represent a
statistically significant observation for the bulk oil observations. However, future removal operations
should take this observed behavior under consideration when designing on scene hydrocarbon/oil water
separation techniques and apparatuses in the unlikely event it occurs on a larger scale with bulk oil at
15C.
Section 3-10: Petroforma Laboratory Analysis Results – Stratification of heavy and light hydrocarbons