manolis l - kevin strowbridge report
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ASSIGNMENT 3: REPORT REVIEW
I nvestigation of Oi l Remediation Options for Shallow Water Shipwrecks in Newfoundland
Waters
Prepared by: Kevin Strowbridge (008801383)
MSTM-410B
Bachelor of Technology
Memorial University of Newfoundland
Supervisor: Ken Baker
Facilitator: Aaron Peach
Revision 4
November 9, 2015
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Letter of Transmittal
155 Ridge Road
St. Johns, Newfoundland A1B 3S7
November 9, 2015
Program CommitteeBachelor of Technology Program
Marine Institute of Memorial University of Newfoundland
P. O. Box 4920
St. Johns, Newfoundland A1C 5R3
Dear Program Committee:
In response to your request on September 8, 2015, I have prepared the following report entitled
Investigation of Oil Remediation Options for Shallow Water Shipwrecks in Newfoundland.This report completes the requirements of both the MSTM 410A and MSTM 410B B-Techcourses.
My research into the field of shipwreck salvage and oil remedial methods has proved to be a veryrewarding experience. I hope that my report will help to raise awareness of the environmental
dangers posed by shallow water shipwrecks and provide information on the best methods
currently available to preform oil remediation of shallow water shipwrecks in Newfoundland
waters. Additionally, I hope to be able to help theManolis L. Citizens Response Committee byproviding them with information that they can use in their attempts to persuade the Canadian
federal government to remove the oil from theManolis L. shipwreck.
I wish to thank my project supervisor, Mr. Ken Baker, my MSTM 410A instructor, ChristopherMcCulloch, my MSTM 410B instructor, Aaron Peach, and my editors, Christine Strowbridge
and Tracey OKeefe.
Should you have any questions about this report, you may contact me at
[email protected]. I look forward to your feedback.
Sincerely,
__________________Kevin Strowbridge
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i
List of Revisions
Revision Description Date
0 Proposal issued for facilitator review July 16, 2015
1Incorporated facilitator feedback and comments and re-
issued the proposalAug 13, 2015
2 Proposal updated and issued for facilitator review Sept 18, 2015
3 Incorporated facilitator feedback and issued the Introduction Oct 9, 2015
4Incorporated facilitator feedback and issued full report for
supervisor and facilitator reviewNov 9, 2015
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Executive Summary
Shallow water shipwrecks, which, for the purpose of this report, are defined as those
wrecks within the 50 meter range of water depth, in Newfoundland (NL) waters contain
hazardous substances, such as petroleum-based oils. Petroleum products that seep from
shipwrecks are devastating to the environment as they are insoluble in water, toxic, and
corrosive. The effects of oil spills from shipwrecks depend on several factors, such as the type
and amount of oil on board at the time of sinking, the characteristics of the affected environment,
the water temperature and depth, shipwreck location, the condition of the ship at the time of
sinking, and the length of time the wreck has been submerged. Currently, there are no
comprehensive methods for environmental risk assessment of shallow water shipwrecks in NL
waters; which causes difficulty on prioritization for remediation options. Additionally, not all
available actions can be taken to minimize or eliminate the environmental risks from these
potentially polluting shipwrecks due to their lack of their applicability and functionality.
The marine industry utilizes several types of petroleum products; the most common being
Marine Diesel Oil (MDO), a light distillate fuel, and Heavy Fuel Oil (HFO), a thick residual fuel.
Three physical properties of these fuels, viscosity, the temperature sensitive measure of a fuels'
resistance to flow, density, the mass per unit of volume, and specific gravity, the ratio between
the density of an object and a reference substance, need to be considered when assessing
shipwrecks. These determine the ability of fuels to flow from a shipwreck and the flow rate of
leakages.
The physical properties of petroleum products must be assessed along with the
environmental conditions in the vicinity of the shipwreck. Since viscosity and density are
temperature dependent, the annual temperature cycle at selected depths must be investigated in
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order to determine how the petroleum products can be expected to behave. At 50 meters,
temperatures are in the range of -2 to +2 deg C. The densest marine fuel, HFO, remains in a near
solid state with a maximum specific gravity of 0.98 at these temperatures, however, its density is
less than the salt water specific gravity of 1.025, which means it can float.
In order to make an informed decision as to which oil remedial options should be
employed, the structural condition of the shipwreck must be assessed. There is sufficient data
available to allow for accurate steel corrosion rate estimate calculations to be performed. These
calculations can help with the risk assessment and shipwreck management decision-making
process. The approximate rate of corrosion in seawater is 0.1 mm/year, however, this rate can
more than double due to wave energy at the surface. Hull plates are generally thick on ships, but,
internal holding tanks and plumbing, ducts and vents are substantially thinner and are often the
first areas to collapse. This can lead to breakup of the hull, which will allow the oil to escape.
Many oil remedial technologies have been successful globally, such as recovery of the
entire wreck, sealing the leaking points and using cofferdams, controlled release of pollutants,
pumping of pollutants from the shipwreck, capping of the entire wreck or of the cargo, or
shipwreck monitoring. Not all of these oil remedial technologies, however, are suitable for use in
Newfoundland shallow water shipwrecks.
The seriousness of a spill does not depend solely on the volume of oil; other factors, such
as location of shipwreck, physical properties of the oil or other pollutants, prevailing marine
conditions and sensitivities of the environment must be assessed. It is essential to undertake an
assessment of both the areas under threat and condition of the shipwreck in order to better
understand the possible consequences of a spill. Shipwreck risk assessment requires an
interdisciplinary approach covering analysis of the shipsconstruction, historical data about the
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ship and documentation from the time of wreckage, corrosion rates, environmental status at the
wreck site, and environmental effects of the hazardous substance(s) onboard. Risks that have
severe consequences and a high probability of occurring require a mitigation plan.
By utilizing theManolis Lshipwreck as a case study, risk factors, such as the corrosion
rates of steel and risk level, were estimated and a shipwreck risk and remedial options matrix
developed that can aid in the prioritization of remediation and environmental response options.
TheManolis Lwas evaluated using all of the analysis methods as laid out in this report and this
demonstrated the functionality of these methods as applied to an actual shipwreck. The risk score
was calculated, the level of consequences was determined and a recommendation for an oil
remediation option for this shipwreck was put forth.
This report's main recommendations are for decision-makers in the shipwreck oil
remediation process to consider the corrosion rate of steel as part of a shipwreck risk matrix, the
creation of a rubric and matrix to analyze each oil remedial option to determine which are best
suited for shallow water shipwrecks in NL waters, and that the Canadian government should
immediately remove the oil from the Manolis L shipwreck or cap the entire shipwreck as
determined by the risk analysis.
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Table of Contents
List of Revisions .............................................................................................................................. i
Executive Summary ........................................................................................................................ ii
List of Illustrations ........................................................................................................................ vii
1.0 Introduction ............................................................................................................................... 1
1.1 Project Purpose ................................................................................................................... 1
1.2 Background ......................................................................................................................... 1
1.3 Scope ................................................................................................................................... 3
1.4 Methodology ....................................................................................................................... 4
2.0 Properties of Common Marine Petroleum Products ............................................................... 5
3.0 Environmental Conditions Data for Newfoundland ............................................................... 7
4.0 Steel Degradation of Shipwrecks .......................................................................................... 105.0 Oil Remedial Technologies................................................................................................... 13
5.1 Recovery of the Entire Wreck........................................................................................... 13
5.2 Sealing the Leaking Points and Using Cofferdams .......................................................... 14
5.3 Controlled Release of Pollutants ....................................................................................... 15
5.4 Pumping of Pollutants from the Shipwreck ...................................................................... 15
5.5 Capping of the Entire Wreck or of the Cargo ................................................................... 16
5.6 Shipwreck Monitoring ...................................................................................................... 16
5.7 Summary of Oil Remedial Options................................................................................... 17
6.0 Shipwreck Risk Analysis Matrix .......................................................................................... 18
6.1 Shipwreck Remediation Decision Process........................................................................ 18
6.2 Definition of Risk Factors and Weights Classes ............................................................... 20
6.2.1 Vessel Type / Tonnage............................................................................................... 21
6.2.2 Volume of Pollutants ................................................................................................. 21
6.2.3 Distance from Coast or a Sensitive Area ................................................................... 22
6.2.4 Environmental Conditions ......................................................................................... 22
6.2.5 Age and Condition of Shipwreck ............................................................................... 23
6.3 Risk Analysis .................................................................................................................... 24
6.3.1 Calculation of Risk Factors ........................................................................................ 24
6.3.2 Risks with Impacts and Rationales ................................................................................ 25
6.3.3 Calculating the Risk Score ......................................................................................... 27
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6.4 Risk Mitigation Strategies................................................................................................. 28
7.0 Case Study:Manolis L.......................................................................................................... 29
7.1 Environmental Conditions Data at the Shipwreck Site..................................................... 30
7.2 Steel Degradation Calculations ......................................................................................... 31
7.2.1 Verification of the Calculations ................................................................................. 32
7.3 Risk Factors ...................................................................................................................... 34
7.4 Calculation of the Risk Score ........................................................................................... 34
7.5 Recommendation for Appropriate Risk Mitigation Strategies ......................................... 35
8.0 Conclusions ........................................................................................................................... 36
9.0 Recommendations ................................................................................................................. 37
References ..................................................................................................................................... 38
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List of Illustrations
Figures
Figure 1-1:Manolis LPrior to Sinking
Figure 2-1: Bunker C Oil
Figure 3-1: Annual Temperature and Salinity Anomalies at Selected Depths (Top Panels)
and Their Decadal Means (Bottom Panels)
Figure 4-1: Effect of Current Velocity on Steel Corrosion Rate
Figure 4-2: Field Results of Steel Corrosion Rates
Figure 4-3: Coating and Steel Degradation Rates
Figure 5-1: Recovery of the Entire Wreck
Figure 5-2: Leak-Sealing Operations
Figure 5-3: Cofferdam on theManolis L
Figure 5-4: Recovering Oil with Booms
Figure 5-5: Hot-Tapping
Figure 5-6: Shipwreck Capping
Figure 5-7: Sonar Image of theManolis L
Figure 6-1: The Basic Structure of the Decision-Making-Process
Figure 7-1:Manolis LPrior to Sinking
Figure 7-2: Notre Dame Bay, Newfoundland
Figure 7-3 Hull Thickness Survey Results As Measured In 2014 with Measurement
Locations
Figure 7-4: Steel Demonstration Piece of Steel Thickness Measured on the Manolis L
Tables
Table 2-1: Physical Properties of Marine Oils
Table 3-1: Results of Various Pressure Conditions at the Shipwreck
Table 5-1: Summary of Oil Remedial Options
Table 6-1: Risk Factor Weights for Vessel Type and Tonnage
Table 6-2: Risk Factor Weights for Volume of Pollutants
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Table 6-3: Risk Factor Weights for Distance from Coast or a Sensitive Area
Table 6-4: Risk Factor Weights for Environmental Conditions
Table 6-5: Risk Factor Weights for Age and Condition of Shipwreck
Table 6-6 Calculation of Risk FactorsTable 6-7: Risk Events with Impacts and Rationales
Table 6-8: Qualitative Risk Classification
Table 6-9: Risk Classification
Table 6-10: Determination of the Risk Score
Table 6-11: Risk Mitigation Strategies
Table 7-1: Structural Steel Corrosion for theManolis L
Table 7-2: Structural Steel Strength Reductions Due To Corrosion for theManolis L
Table 7-3: Average Hull Thickness
Table 7-5: Calculation of the Risk Score for theManolis L
Table 7-6: Recommended Risk Mitigation Strategies for theManolis L
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1.0 Introduction
1.1 Project Purpose
The purpose of this report is to develop a tool for quantitative risk and remedial options
assessment of potentially polluting shallow water shipwrecks in Newfoundland (NL) waters.
This report examines current shipwreck oil remedial options to determine which is best suited for
shallow water shipwrecks in NL waters. By utilizing the Manolis L shipwreck as a case study,
risk factors, such as the corrosion rates of steel, can be estimated and a shipwreck risk and
remedial options matrix developed that can aid in the prioritization of remediation and
environmental response options.
1.2 Background
Shallow water shipwrecks, which, for the purpose of this report, are defined as those
wrecks within the 50 meter range of water depth, in NL waters contain hazardous substances,
such as petroleum-based oils, that can cause harm to the marine environment. Oil spills from
shipwrecks pose a danger to flora and fauna and cause damage to sea and shore ecosystems.
Many of the petroleum chemicals are toxic, carcinogenic or can be absorbed into the tissues of
marine organisms (Landquist, H, et al., 2013). These toxins can make it up the marine food
chain; from plankton to fish to other marine mammals, and even humans.
Large oil spills caused by bilging or grounding of ships often receive swift environmental
responses. These catastrophic spills are extensively covered by media as the amount of oil
dissipated over the water surface underscores the seriousness of the spill (Rogowska, Namienik,
2010). Shipwrecks can potentially cause spills that are on par with the large oil spills, however,
because spills from shipwrecks, known as chronic oil spills, are not instantaneous and do not
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usually cause oil accumulate on the water surface (Landquist, H, et al., 2013), they are often
ignored by the media and do not receive adequate environmental responses.
The effects of oil spills from shipwrecks depend on numerous factors, such as the type
and amount of oil on board at the time of sinking, the characteristics of the affected environment,
the water temperature and depth, wreck location, the condition of the ship at the time of sinking,
and the length of time the wreck has been submerged (Landquist, H, et al., 2013).
Currently, there are no comprehensive methods for environmental risk assessment of
shallow water shipwrecks in NL waters; which causes difficulty on prioritization of remediation
options (Alcaro, L.et al., 2007). Additionally, not all available actions can be taken to minimize
or eliminate the environmental risks from these potentially polluting wrecks due to their lack of
their applicability to, and functionality in, the subject region, which include:
recovery of the entire wreck
sealing the leaking points
installing an oil capturing device
controlled release of pollutants
pumping of pollutants
capping of the entire wreck or of the cargo
wreck monitoring
On January 18, 1985, the 5-year old, 121.85-meter long, steel hulled Liberian cargo
carrier,Manolis L,as shown in Figure 1-1,went off course and struck Blowhard Rock in Notre
Dame Bay, NL, at a speed of 14 knots (Transport Canada, 1985, p.2). This resulted in severe
damage to the hull and ultimately led to the sinking of the vessel in an area identified by
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Environment Canada as an ecologically sensitive area
(CPAWS, 2009, p.60). In late March, 2013, a severe
storm with extreme tidal conditions hit the area and
caused the shipwreck to shift and experience
additional hull damage (CBC News, 2015).
Additional damage to a shipwreck can increase the risk of oil leakage (Landquist, H., et al.,
2014). The Notre Dame Bay region relies heavily on tourism and the fishery for its economy
(CBC News, 2015) and one or more oil spills from the Manolis L shipwreck could be
environmentally devastating. Even more serious is the possibility of a chronic oil spill, which
occurs over decades (Landquist, H, et al., 2013).
TheManolis Lis not an isolated case; shallow water shipwrecks eventually reach a point
in their decay curve where they experience structural changes that may lead to oil pollution
(Landquist, H, et al., 2014). Using theManolis Las a case study allows for practical application
of this projects research and demonstration as to how this can be applied to other shallow water
shipwrecks in NL Waters.
1.3 Scope
The scope of this project includes:
overview of shallow water shipwreck steel degradation in NL waters
calculation of the corrosion rate of steel shipwrecks so as to develop a shipwreck risk
matrix
summary and analysis of current shallow water shipwreck oil remedial technologies
creation of a rubric and matrix to analyze each oil remedial option to determine which
are best suited for shallow water shipwrecks in NL waters
Figure 1-1:Manolis L Prior to SinkingSource: CBC News
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recommendations on which oil remedial technologies are best suited for shallow
water shipwrecks in NL waters
The scope of this project does not include:
shipwrecks in water deeper than 60 meters
shipwrecks outside of 2 kilometers from the coastline
non-oil carrying vessels
technology that does not have proven functional and operational profiles
oil remediation costs
1.4 Methodology
The research used to support this project was available literature from secondary sources.
The literature mainly focused towards three types of sources. The first source was journal articles
and papers on the topic of structural degradation in shipwrecks by engineers, experts or
researchers (Kuroda et al., 2008). The second type of source was on the topic of oil remedial
methods and options in the form of papers published by engineers, experts or researchers in
periodicals, articles, or magazines (Mazarakos, Andritsos & Kostopoulos, 2012). The third
source was information and data obtained from companies that operate in the oil remedial sector
(Environment Canada, 2006). Additional sources were used as needed from the MUN and
Marine Institute libraries.
The analysis of the secondary sources was a very critical stage in the development of the
project report. The analysis was qualitative and:
described and summarized the research data
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analyzed the applicability of various remedial methods and options
forecast outcomes
The project report considered current shipwreck oil removal technologies (Mazarakos et al.,
2012) to determine which is best suited for shallow water shipwrecks in NL waters. A shipwreck
in Notre Dame Bay, NL, the Manolis L, was used as a case study (Transport Canada, 1985) for
practical application of this projects research and demonstration as to how this can be applied to
other shallow water shipwrecks in NL Waters.
2.0 Properties of Common Marine Petroleum Products
Crude oil, as shown in Figure 2-1, has been the
most common source of fuel oils for marine use since the
solid fuel, coal, was phased out in 1912. Britains Queen
Elizabeth-class battleships were among the first vessels
designed and built to be powered solely by liquid fuels.
These vessels were successful and the use of liquid fuels
spread to general use in the marine shipping industry
(Dahl, 2001). For the purposes of oil remedial options for shipwrecks, only vessels built after
1912, therefore, need be considered.
An understanding of the physical properties of petroleum products is necessary in order
to develop an understanding of the dangers they pose when they leak from shipwrecks.
Petroleum products that seep from shipwrecks are devastating to the environment (Landquist, H,
et al., 2013) as they are insoluble in water, toxic, and corrosive. The marine industry utilizes
several different types of these products; the most common being Marine Diesel Oil (MDO), a
Figure 2-1:Bunker C Oil
Source: Environment Canada
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light distillate fuel, and Heavy Fuel Oil (HFO), a thick residual fuel. The critical specifications,
those which affect flow rates and buoyancy, are shown in Table 1-1.
Oil Type
Viscosity
0 Ckg/m*s
Viscosity
15 Ckg/m*s
Density
0 Ckg/m3
Density
15 Ckg/m3
Specific Gravity
0 C (SW)T/m3
Specific Gravity
15 C (SW)T/m3
MDO 129 14 996 890 - 920 0.97 0.86 - 0.89
HFO 883 486 980 960 -1010 0.95 0.93 - 0.98
Table 2-1:Physical Properties of Marine Oils
Adapted fromISO 8217:2005 Petroleum products - Fuels (class F) - Specifications of marinefuels, Tables 1 and 2. Retrieved from http://www.chevronmarineproducts.com/products/iso-
specs.aspx
Lubricants, hydraulics, and greases are not considered herein as the quantities of each are
relatively small in comparison to the fuel oils.
Three physical properties of these fuels, viscosity, the temperature sensitive measure of a
fuels' resistance to flow, density, the mass per unit of volume, and specific gravity, the ratio
between the density of an object, and a reference substance, need to be considered when
assessing shipwrecks. These determine the ability of fuels to flow from a shipwreck and the flow
rate of leakages (Pounder & Woodyard, 2004). As MDO is the lighter fuel, it will leak easier
than HFO when an escape route from a shipwreck forms. Lighter oils are able to escape through
narrow cracks, vent pipes, and broken internal pipes and equipment and tend to form large thin
oil sheens that can cover large surface areas. Evaporation in open-water spills lessens the
negative impacts (Milwee, 1996).
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3.0 Environmental Conditions Data for Newfoundland
The petroleum products physical properties must be assessed along with the
environmental conditions of the region under consideration; in this case, Newfoundland. Because
viscosity and density are temperature dependent, the annual temperature cycle at selected depths
must be investigated in order to determine how the petroleum products can be expected to
behave. For the purpose of this report, shallow water depth is deemed to be 50 meters. Figure 1
shows the water temperatures at both the surface and at 50 meters of depth as measured on
Newfoundlands northern coastline. This represents the best-case scenario due to the colder, at
depth, water temperatures which keep heavy fuel oils in a near solid form and less lightly to seep
from a shipwreck.
At 50 meters, temperatures are in the range of -2 to +2 deg C (Colbourne, 2004). The
densest marine fuel, HFO, remains in a near solid state with a maximum specific gravity of 0.98,
however, its density is less than the salt water specific gravity of 1.025. Since the HFO specific
gravity is less than the salt water, the HFO will float should it leak from the shipwreck and,
hence, has the potential to create spills and cause environmental damage.
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Figure 3-1:Annual Temperature and Salinity Anomalies at Selected Depths (Top Panels) andTheir Decadal Means (Bottom Panels)
Source: Colbourne, 2004
Whether oil flows from a ruptured tank depends on more than the viscosity and density of
the oil. The hydrostatic pressure of the water column will not allow oil to easily escape. If the
pressure in the tank is higher than the water pressure, the oil will flow out of the tank. If the
water pressure is higher, then the oil will remain in the tank (Milwee, 1996).
However, other environmental forces can act on the shipwreck and lead to oil spilling
from a tank. Subsea currents can create pressure differences that allow the oil to escape. These
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currents can also force water into tanks, which will displace the oil and force it out of the tank(s)
(Milwee, 1996).
The rising and falling of the tides can affect the pressure differential at the wreck site.
Much like the operation of a displacement pump, a continual tidal cycle can pump oil from the
tanks of a shipwreck. This force is increased when coupled with tidal or storm surges (Milwee,
1996). As the tide rises, the water pressure increases and is forced into the tank(s). Later, as the
tide falls, oil flows out of the tank(s) as the water pressure drops below that of the pressure inside
of the tank(s). Oil will continue to flow out of the tank(s) until the pressures equalize. Table 1-2
shows the effect of different pressure situations.
Pressure Condition Result
Pressure in Tank = Water Pressure No Leakage
Pressure in Tank > Water Pressure Oil flows out of tank(s)
Pressure in Tank < Water Pressure No Leakage
Table 3-1:Results of Various Pressure Conditions at the Shipwreck
Source: author
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4.0 Steel Degradation of Shipwrecks
In order to make an informed decision as to which oil remedial options should be
employed, the structural condition of the shipwreck must be assessed. There is ample data
available to allow for accurate steel corrosion rate estimate calculations to be performed. These
calculations can help with the risk assessment and shipwreck management decision making
process.
Many factors determine the state of steel degradation of a wreck:
the ship's construction materials
the wreck becoming covered in sand or silt
the salinity of the water the level of destruction involved in the ship's loss
the depth of water at the wreck site
the strength of tidal currents or wave action at the wreck site
the exposure to surface weather conditions at the wreck site
the presence of marine animals that consume the ship's fabric
temperature
the acidity (pH) and other chemical characteristics of the water at the site
It is well known that corrosion rate of steel in seawater is influenced by dissolved
oxygen, temperature, marine growth and so on, and increases as current velocity increases
(Kuroda, et al, 2008). Figure 4-1 graphs the effect of current velocity on steel corrosion rate.
Figure 4-1:Effect of Current Velocity on Steel Corrosion Rate
Source: Kuroda, et al, 2008
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The approximate rate of corrosion in seawater is 0.1 mm/year. However, this rate can
more than double due to wave energy at the surface (MacLeod, 2011). Hull plates are generally
thick on ships, however, internal holding tanks and plumbing, ducts and vents are substantially
thinner and are often the first areas to collapse (MacLeod, 2011). This can lead to breakup of the
hull.
Corrosion rates for individual ships are affected by dissolved oxygen and temperatures at
the wreck site (MacLeod, 2010). Baseline corrosion rates do not account for natural events, such
as storm surges and strong currents. Localized corrosion from pitting or microbes can be
important factors and, if occurs much faster than the baseline rate, is more likely to cause
structural failure sooner, however, these cannot be predicted (MacLeod, 2011).
Through the use of experimentation with steel corrosion rates in salt water, a more
accurate gauge of corrosion rates can be utilized (Kuroda, et al, 2008). At depths in the 50 meter
range, the steel corrosion rate values can be taken as 0.21 mm/year, as seen in Figure 4-2.
Figure 4-2:Field Results of Steel Corrosion RatesSource: Kuroda, et al, 2008
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The DNV Hull Inspection Manual (DNV, 2007) provides guidance to ship operators on
maintaining control of ships structural conditions. Figure 4-3 shows the average rates at which
coating systems breakdown and that steel will degrade once the coatings breakdown. This can be
applied to sunken ships. Depending upon the coating condition of the ship at the time of loss, the
coatings will breakdown in approximately 6 years. It then only takes 4 years for the steel to
degrade to the point where holes will begin to form.
Figure 4-3: Coating and Steel Degradation Rates
Source: DNV, 2007
By considering all of these factors, the following formula can be derived that will provide an
estimate of the steel corrosion rate:
Estimated Corrosion (mm) = Corrosion Rate (mm/yr) x [Ship Submersion Time (years) -
Coating Breakdown (years)]
This can be extended to arrive at a formula to estimate the remaining steel thickness:
Estimated Steel Thickness Remaining (mm) = Original Steel Thickness (mm) - Estimated
Corrosion (mm)
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5.0 Oil Remedial Technologies
Many oil remedial technologies have been successful globally. New technology and oil
remedial methods are continually being developed and improved upon. Several operations can be
carried out in order to evaluate, minimize and eliminate the environmental risks deriving from
potentially polluting wrecks:
recovery of the entire wreck
sealing the leaking points and using cofferdams
controlled release of pollutants
pumping of pollutants from the shipwreck
capping of the entire wreck or of the cargo
shipwreck monitoring
Not all of these oil remedial technologies, however, are suitable for use in Newfoundland
shallow water shipwrecks. This section aims to provide an overview of each technology along
with rational towards applicability.
5.1 Recovery of the Entire Wreck
Recovery of the entire shipwreck is
considered to be the best oil remediation option. Not
only are the oils removed, but also all other
potentially hazardous materials onboard; such as the
oily waste, cargo residues, chemicals in the
equipment, hydraulic oils, lubricants, and greases.
The wreck removal process is shown in Figure 5-1. Shallow water shipwreck recovery in
Newfoundland waters is a viable option for vessels that are mainly intact and have not degraded
substantially (Alcaro et al., 2007).
Figure 5-1:Recovery of the Entire Wreck
Source: SMIT Salvage
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Many shipwrecks, however, are not good candidates for recovery as they are damaged to
the point of being fragile. Recovery attempts of vessels in this condition can lead to vessel
breakup; which could cause a greater environmental problem. The longer a vessel remains
underwater, the more degradation will occur (Milwee, 1996).
5.2 Sealing the Leaking Points and Using Cofferdams
Sealing the leaking points, as shown in figure 5-2,
is a temporary measure that is used to slow the flow of
oils from a wreck until a more permanent solution can be
decided upon. It is typically the first option to consider in
the event of an emergency.
Sealing can be performed with a variety of tools
and materials to plug leaks, using either a ROV or diver
(Alcaro et al., 2007) and is a viable temporary option for shipwrecks in Newfoundland waters.
Another level of protection can be included
with this option; use of an oil-capturing system, such
as a cofferdam (shown in Figure 5-3). Cofferdams can
be placed over leaking points to trap any leaking oil.
This oil can then be pumped from the cofferdam on a
regular basis.
Cofferdam use must be considered to be temporary solution as they do not prevent the oil
from leaking from the shipwreck. The shipwreck continues to degrade and, eventually, the oil
leakages can become too numerous or the seepage flow rate can increase to a point where the
volume of the cofferdam is inadequate.
Figure 5-2:Leak-Sealing Operations
Source: French Navy
Figure 5-3: Cofferdam on the Manolis L
Source: CCG
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5.3 Controlled Release of Pollutants
This method is implemented by drilling holes in
the hull of the shipwreck to puncture the tank, thereby
allowing controlled release of the pollutants (Alcaro et al.,
2007). The controlled discharge of pollutants, however,
has limitations. The pollutant must be able to float so that
it can be captured and collected on the surface by oil
booms. This can be seen in figure 5-4. Because of the use
of surface vessels and floating oil booms, ideal sea and weather conditions are required; a rarity
in Newfoundland.
5.4 Pumping of Pollutants from the Shipwreck
The most common option employed to pump
pollutants from shipwrecks is the hot-tap technique
(Alcaro et al., 2007), as shown in Figure 5-5. This
method involves the drilling of several holes in the
shipwreck hull and installing pipe flanges. This is
achieved using specialized tools that do not allow
leakages to occur during the procedure. Several hot-
tap flanges and holes must be installed in a tank to mount the pump, provide make-up water, and
insert heating coils. Sometimes it results necessary to heat the transfer line of the pump steam
into the oil tank to melt the oil and reduce its viscosity, which improves flow.
Hot-tapping can be performed by divers and ROVs and is a viable option in
Newfoundland waters.
Figure 5-4:Recovering Oil with
BoomsSource: Markleen Oil Spill
Technologies
Figure 5-5:Hot-TappingSource: Markleen Oil Spill
Technologies
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5.5 Capping of the Entire Wreck or of the Cargo
This option aims to completely cover the wreck or the cargo, as shown in Figure 5-6, in
order to avoid the leakage of pollutants components into the marine environment (Alcaro et al.,
2007). The advantages of this type of technology include:
isolation of pollutants and preventing
their dispersion by the use of capping
materials with a low permeability to
fluids
protection of the shipwreck from any
contact with fishing equipment or
other human activities that can cause
an increase of deteriorating rate
reduction of the corrosion rate of
metals and steels
transformation of pollutants if the
capping material is added with
reacting and neutralizing compounds
The capping material should be made of crushed rocks and is a viable option in
Newfoundland waters. The large quantity of capping materials and transport to the shipwreck
site, however, may prove to be obstacles.
5.6 Shipwreck Monitoring
Monitoring the shipwreck involves the use of
sonar, divers, ROVs, magnetometers, and even
enlisting the help of local residents to report any oil
spills. An example of a sonar image is shown in
figure 5-7. Even if sonar imaging provides us with
the position of a wreck on the bottom, only close
visual examination (camera, diver or ROV) can
Figure 5-6: Shipwreck Capping
Source: DEEPP Pro ect
Figure 5-7: Sonar Image of the
Manolis L
Source: CCG
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provide us with details (location of holes, leaks, corrosion, etc.) (Alcaro et al., 2007). The French
Department of Labor authorizes tank diving to a depth of 60 meters. Since this paper considers
water depths below 60 meters to be shallow water, this is a viable option in Newfoundland
waters.
Shipwreck monitoring, however, is not an oil remediation solution. It simply provides
notice that an oil spill has occurred or is about to occur.
5.7 Summary of Oil Remedial Options
This section discussed the various oil remedial options which are in use for shipwreck
remediation globally. Table 5-1 summaries these options.
Option Description
Viable for
NFLD
(Y/N)
Permanent
Solution
(Y/N)
A recovery of the entire wreck Y Y
B sealing the leaking points and using cofferdams Y N
C controlled release of pollutants N Y
D pumping of pollutants from the shipwreck Y Y
E capping of the entire wreck or of the cargo Y Y
F shipwreck monitoring Y N
Table 5-1: Summary of Oil Remedial OptionsSource: Adapted from Alcaro, 2007
Only options which are viable for Newfoundland waters will be considered further in this
report. Temporary solutions will be considered further as these are acceptable options in some
situations.
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6.0 Shipwreck Risk Analysis Matrix
The seriousness of a spill does not depend solely on the volume of oil; other factors, such
as location of shipwreck, physical properties of the oil or other pollutants, prevailing marine
conditions and sensitivities of the environment must be assessed. It is, therefore, crucial to
undertake an assessment of both the areas under threat and condition of the shipwreck in order to
better understand the possible consequences of a spill (Alcaro, et al, 2007).
Ship wreck risk assessment requires an interdisciplinary approach covering analysis of
ship construction, historical data about the ship and documentation from the time of wreckage,
corrosion rates, environmental status at the wreck site, and environmental effects of the
hazardous substance/s onboard. Consideration of these will lead to the creation of a rubric and
matrix to analyze each oil remedial technology to determine which are best suited for shallow
water shipwrecks in NL waters.
Risks that have severe consequences and a high probability of occurring require a
mitigation plan.
6.1 Shipwreck Remediation Decision Process
The general process of risk management consists of a number of steps, as shown in
Figure 6-1. Initially it involves an establishment of the context where the scope and goal of the
risk management work is stated. This is followed by the risk assessment where risk identification
is performed which implies identification of areas of impact, events, sources of risks and
potential causes and consequences. Risk assessment also involves a risk analysis process to
develop an understanding of the risk and to provide input to the subsequent risk evaluation. An
evaluation of what risks to consider and how to prioritize among them is included in the risk
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evaluation step, together with a comparison of possible alternatives to mitigate the risks. This
provides support to the decision-makers on benefits and limitations of possible risk treatment
alternatives (Landquist, 2013).
Figure 6-1: The Basic Structure of the Decision-Making-ProcessSource: Adapted from Landquist, 2013
Shipwrecks need to be assessed and prioritized to ensure that available resources can be used
efficiently to reduce risk. This proactive approach involves the inspecting and performance of
corrective actions, when needed, prior to the occurrence of any leakages. A well-structured risk
assessment that can identify and prioritize shipwrecks is needed for a proactive strategy to be
effective. Moreover, such an assessment can help prioritize between remedial alternatives and
provide necessary decision support. Prioritizing sunken vessels will help resource managers and
governments use resources effectively and assure stakeholders that the problem has been
carefully assessed.
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6.2 Definition of Risk Factors and Weights Classes
Risk assessment involves the overall process of identifying risk, analyzing risk and
evaluating risk. The aim of risk identification is to identify potential risks and gather relevant
information on these risks. This identification is critical as risks that are not identified will not be
considered in the supplementary process.
Risk management begins with the establishment of the context where the objectives and risk
criteria are set. Five factors were chosen to build a matrix of wreck threats:
1. vessel type / tonnage
2.
volume of pollutants
3. distance from coast or a sensitive area
4. environmental conditions
5. age and condition of shipwreck
These components provide a measure of impact that a leaking ship will have on the
environment. Each factor is classed between 1 (least dangerous) and 10 (most dangerous). Risk
factors were then summed to produce the final risk rating for a maximum score of 50. Large oil
tankers found in shallow, near shore waters in areas of high marine biological diversity are
ranked highest, for example, while smaller ships in deeper waters are of lowest priority.
Risk Index: Recall that the under riding criteria are:
ships built after 1910
steel hulled
shallow waters (50 m range)
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6.2.1 Vessel Type / Tonnage
The tonnage of ships is considered as larger vessels carry larger fuel reserves. Tonnage
values in the dataset range from 1000 to 50,000 tons. Oil tankers receive more points within the
scoring due to their significant cargo oil capacity (Grennan, 2010). Table 6-1 shows the risk
factor weights for vessel type and tonnage.
Class Description Risk Factor Weights
A < 2,000 tons 1
B 2,000 - 2,999 tons 2
C 3,000 - 3,999 tons 3
D 4,000 - 4,999 tons 4
E > 5,000 tons 5
F Tanker Vessel add 3
Table 6-1:Risk Factor Weights for Vessel Type and Tonnage
Source: Adapted from Alcaro, 2007
6.2.2 Volume of Pollutants
Unless documentation can prove that vessel tanks are not 100% full, it should be assumed
that the vessel tanks are 100%. In cases where vessel tank capacities or design drawings are not
available, capacities from similar ships should be used. The total volume includes the total vessel
fuel capacity and any cargo that contains pollutants. Table 6-2 shows the risk factor weights for
volume of pollutants.
Class Pollutant Volume (m3) Risk Factor Weights
A < 200 1
B 200 - 299 2C 300 - 399 3
D 400 - 500 4
E > 500 5
Table 6-2:Risk Factor Weights for Volume of PollutantsSource: Adapted from Alcaro, 2007
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6.2.3 Distance from Coast or a Sensitive Area
The distance from shore is a critical factor as any pollutants that leak from a near-shore
shipwreck will reach the shoreline within a few hours (Alcaro, et al, 2007)). This drastically
reduces the oil remediation response time. Additionally, near-shore shipwrecks are usually
located in shallow waters. The reduced depth of the water column means that the pollutant does
not have the opportunity to dilute or dissipate. Table 6-3 shows the risk factor weights for
distance from coast or a sensitive area.
Class Distance (km) Risk Factor WeightsA > 5 1
B 3 -4 2
C 2 -3 3
D 1 - 2 4
E < 1 5
Table 6-3:Risk Factor Weights for Distance from Coast or a Sensitive Area
Source: Adapted from Alcaro, 2007
According to Alcro, et al (2007), in a few hours, oil will reach the coast if the shipwreck is
located 1 km offshore. Within a day, even without the effects of tides or currents, a floating oil
slick will range from 616 km. In a few days, the distance will range from 1680 km.
6.2.4 Environmental Conditions
As shown is previous sections, the environmental conditions at the shipwreck site are an
important consideration. The salient levels, current velocities and temperatures affect both the
behaviors of the pollutants and the corrosion rates of the shipwreck. The actions of the tidal cycle
and storm surges also affect possible outcomes. Table 6-4 shows the risk factor weights for
environmental conditions.
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Class Description Risk Factor Weights
A salient levels > 35 1
B tidal range > 0.6 m 2
C > 4 storm surges/ year 3
D current velocities > 4 m/s 4
E temperatures > 2 C 5
Table 6-4:Risk Factor Weights for Environmental Conditions
Source: Adapted from Alcaro, 2007
It is possible that more than one of these risk factors can be present simultaneously. As such,
the total risk factor weight for this consideration is the total sum of all of the weights, 15.
6.2.5 Age and Condition of Shipwreck
The length of time since the sinking of a vessel affects how much steel deterioration the
shipwreck will experience; as shown in previous sections. The amount of damage a vessel
sustains at the time of loss is an important factor, as well if the vessel remains intact. Table 6-5
shows the risk factor weights for age and condition of shipwreck.
Class Description Risk Factor WeightsA 0-9 years underwater 1
B 10-19 years underwater 2
Cconsiderable damage at
time of loss3
D shipwreck not intact 4
E > 20 years underwater 5
Table 6-5:Risk Factor Weights for Age and Condition of Shipwreck
Source: Adapted from Alcaro, 2007
It is possible that more than one of these risk factors can be present simultaneously. As such,
the total risk factor weight for this consideration is the total sum of all of the weights, which is
12.
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6.3 Risk Analysis
Risk analysis allows for the development of a deeper understanding of the potential risks.
This provides input to the risk evaluation, if there is a need for treatment and also the decision on
suitable mitigation options.
The risk analysis requires a method to determine the amount of risk and the possible
outcomes of these risks. Next, the level of risks must be defined in order to prioritize shipwrecks
for oil remediation. Finally, the oil remedial options must be evaluated against the risk levels.
6.3.1 Calculation of Risk Factors
The determination of the risk factor is based on the ratio of the Class of Distance RF / Class
of Volume RF:
Risk Factor (RF) = Class of Distance RF / Class of Volume RF
These two risk factors are the largest contributors to the size and severity of a potential oil
spill. Table 6-6 shows the calculation of risk factors.
Class of
Distance
Class of
Volume RF
Class of
Distance
Class of
Volume RF
Class of
Distance
Class of
Volume RF
1 1 1.00 3 1 3.00 5 1 5.00
1 2 0.50 3 2 1.50 5 2 2.50
1 3 0.33 3 3 1.00 5 3 1.67
1 4 0.25 3 4 0.75 5 4 1.25
1 5 0.20 3 5 0.60 5 5 1.00
2 1 2.00 4 1 4.00
2 2 1.00 4 2 2.00
2 3 0.67 4 3 1.33
2 4 0.50 4 4 1.00
2 5 0.40 4 5 0.80
Table 6-6 Calculation of Risk FactorsSource: Adapted from Alcaro, 2007
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6.3.2 Risks with Impacts and Rationales
All of the risk factors work to increase the probability of a spill occurring. It is currently
impossible to calculate the probability of a shipwreck releasing pollutants in the shallow waters
of Newfoundland due to the lack of historical data; which is a good thing as this means that the
number of spills that have occurred in the subject region is low. The best we can presently
achieve is a rating system for the severity of risk.
Even though probabilities cannot currently be estimated, the events that can lead to a possible
spill can be itemized (Landquist, et al, 2014). The most common are shown in Table 6-7.
No. Risk Event Rationale
1 Corrosion Steel corrodes in salt water at a rate that can be calculated
2 Diving Shipwrecks can be damaged by divers
3 Landslides/earth quakesShifting of a shipwreck can introduce forces and stresses that
can cause tanks to rupture
4 Ship traffic
Shipwrecks in shallow waters are susceptible to damage from
ship traffic. Anchors, for example, can puncture a tank on a
shipwreck
5 Storms/extreme weatherShifting of a shipwreck can introduce forces and stresses that
can cause tanks to rupture
6 TrawlingA collision between a trawl and shipwreck can cause tanks to
rupture
Table 6-7:Risk Events with Impacts and RationalesSource: Author
The risk is based on the consequence of the risks compared to the likelihood of the risks
occurring. This comparison is illustrated in Table 6-7. Table 6-8 illustrates the degree of
consequence of each risk factor and the likelihood of a particular risk factor happening. It also
illustrates the impact potential if such risks are realized.
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These possible events can be rated on a level of hazard based on the potential for the event to
occur and the resulting consequences. The impact levels are:
Minor
Moderate Serious
Minor corresponds to wrecks with a limited damage-potential due to the non-polluting
category of the pollutant or the low risk factor score.
Moderate denotes wrecks that may have impacts. Special care and monitoring should be
performed before making a decision: neutralization of the risk or leave the wreck as it is, taking
into account the accessibility of the pollutants (depth, position of the wreck at the sea bottom,
location of the wreck, sea conditions, etc.).
Serious means that potentially very severe effects are expected. These top priority cases
should receive immediate action plan and mitigation.
Table 6-8 shows the risk classification with the estimated impact potential and consequences.
Risk Risk Factor Likelihood ImpactPotential
Consequence
1 Corrosion High Serious Serious
2 Diving Low Minor Serious
3 Landslides/earth quakes Medium Serious Serious
4 Ship traffic Medium Serious Serious
5 Storms/extreme weather High Serious Serious
6 Trawling Low Minor Serious
Table 6-8: Qualitative Risk Classification
Source: Author
As can be seen in Table 6-9, the consequence for each risk factor is serious. No matter how
low the likelihood of a risk factor occurring may be, the consequence is that a spill is the end
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result; which is serious. This serves to highlight the need for oil remediation strategies to be
considered following the loss of any vessel.
Consequence
Likelihood Nil Minor Moderate Major Severe
Almost Certain 5 10 15 20 25
Likely 4 8 12 16 20
Possible 3 6 9 12 15
Unlikely 2 4 6 8 10
Rare 1 2 3 4 5
Impact key
01-04 = Minor
05-09 = Moderate
10-16 = Major
17-25 = Severe
Table 6-9:Risk Classification
Source: Author
6.3.3 Calculating the Risk Score
After the five risk factors have been analyzed, the results can be recorded and an overall
(total) risk score obtained. The higher the risk score, the higher the need for an oil remediation
strategy. Table 6-10 provides the means to calculate the risk score
Risk FactorRisk Factor
Weights
Max
Weight
Vessel type / tonnage 8
Volume of pollutants 5
Distance from coast or a sensitive area 5
Environmental conditions 15
Age and condition of shipwreck 12
TOTAL SCORE: 45Impact key
01-09 = Minor
10-29 = Moderate
30-45 = Severe
Table 6-10:Determination of the Risk Score
Source: Author
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6.4 Risk Mitigation Strategies
As a result of the risk analysis, the utilization of risk mitigation strategies, which, in the case
of shipwrecks refers to the oil remediation options, in an effort to minimize risks must be
undertaken. Table 6-11 outlines the risk mitigation strategies, determined for the associated risks
and is dependent upon the risk score of the shipwreck.
Oil Remedial Option
Risk Identification A B C D E F
Risk score = Minor Y Y Y Y Y
Risk score = Moderate N Y Y Y Y
Risk score = Severe N N Y Y Y/N
Key
Option Description
A recovery of the entire wreck
B sealing the leaking points and using cofferdams
C controlled release of pollutants
D pumping of pollutants from the shipwreck
E capping of the entire wreck or of the cargo
F shipwreck monitoring
Table 6-11:Risk Mitigation StrategiesSource: Author
Option A is not viable with risk scores above Minor as the shipwreck will have
deteriorated to the point where recovery of the shipwreck may cause severe environmental
damage.
Option B is not viable with risk scores above Moderate as this option is a temporary
solution and the shipwreck will require permanent solutions.
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Option F with Severe risk scores receives a Y/N because at this level of risk, oil
remediation should have already occurred. The wreck should be monitored, however, in the
event that not all of the oil was captured during the oil remediation process.
It is expected that all risks are factored in to these strategies. If however, other risks develop,
it is hoped that their effects may be analysed and appropriate mitigation strategies can be put in
place.
7.0 Case Study: Manolis L
On January 18, 1985, the 5-year old, 121.85-meter
long, steel hulled Liberian cargo carrier, Manolis L
(shown in Figure 7-1), went off course and struck
Blowhard Rock in Notre Dame Bay, NL, at a speed of 14
knots (Transport Canada, 1985, p.2). This resulted in
severe damage to the hull and ultimately led to the sinking
of the vessel in an area identified by Environment Canada as an ecologically sensitive area
(CPAWS, 2009, p.60). In late March, 2013, a severe storm with extreme tidal conditions hit the
area and caused the shipwreck to shift and experience additional hull damage. Additional
damage to a shipwreck will increase the risk of oil leakage (Landquist, H., et al., 2014). The
Notre Dame Bay region relies heavily on tourism and the fishery for its economy (CBC News,
2015) and one or more oil spills from the Manolis L shipwreck could be environmentally
devastating. Even more serious is the possibility of a chronic oil spill, which occurs over decades
(Landquist, H, et al., 2013).
Figure 7-1:Manolis L Prior to
SinkingSource: CBC News
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TheManolis Lwill be evaluated using all of the analysis methods as laid out in previous
sections. This will serve to demonstrate the functionality of these methods as applied to an actual
shipwreck. The risk score will be calculated and a recommendation for an oil remediation option
will be put forth.
7.1 Environmental Conditions Data at the Shipwreck Site
According to (Rao & Gregory, 2009), Notre dame Bay is a 6000 km2inlet of the Atlantic
Ocean located on the northeast coast of Newfoundland. It contains many islands including Fogo
Island, Change Islands, Exploits Islands and Twillingate. The tides are semi-diurnal with a height
difference of approximately 1 m between high and low tides. Fast ice persists in the small bays
and inlets for most of the season. Notre dame Bay falls within the North Shore Forest ecoregion,
and is located in the Newfoundland Shelf region of Parks Canadas National Marine
Conservation Areas System. The subject area is shown in Figure 7-2.
Figure 7-2:Notre Dame Bay, NewfoundlandSource: Oceanviewer.org
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7.2 Steel Degradation Calculations
Based on the field results of steel corrosion rates (Kuroda, et al, 2008), and structural
information from similar ships built in 1980, table 7-1 shows calculations that were completed
for theManolis Lusing the following formulas:
Estimated Corrosion (mm) = Corrosion Rate (mm/year) x [Ship Submersion Time (years) -
Coating Breakdown (years)]
Estimated Steel Thickness Remaining (mm) = Original Steel Thickness (mm) - Estimated
Corrosion (mm)
Shell Internal 1 Internal 2
Original Steel Thickness (mm) 19 12 9
Coating Breakdown (years) 5
Corrosion Rate (mm/yr) 0.21
Ship Submersion Time (years) 30
Estimated Corrosion: 0.235 x 30
= 7.05 mm
Estimated Steel Thickness Remaining: 257.05 127.05 97.05
= 11.95 mm 4.95 mm 1.05 mm
Table 7-1: Structural Steel Corrosion for the Manolis LSource: Author
This data can be represented as average strength reductions by dividing the estimated steel
thickness by the original steel thickness, as shown in table 7-2.
Shell Internal 1 Internal 2
Original Steel Thickness (mm) 19 12 9Estimated Steel Thickness Remaining 11.95 4.95 1.05
average strength reductions 37.11% 58.75% 88.33%
Table 7-2: Structural Steel Strength Reductions Due To Corrosion for the Manolis L
Source: Author
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7.2.1 Verification of the Calculations
Figure 7-3 shows the hull thickness survey results as measured in 2013 by Seaforth
Figure 7-3Hull Thickness Survey Results As Measured In 2014 with Measurement Locations
Source: Seaforth, 2014
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The average hull thickness is shown in Table 7-3.
Reading
No.
Thickness
(mm)
Reading
No.
Thickness
(mm)
1 13.2 12 9.2
2 12 13 10.63 4.7 14 10.8
4 9.6 15 10
5 13.1 16 11.1
6 11.7 17 10.2
7 10.4 18 10
8 10.4 19 10.6
9 13.8 20 11.2
10 10.8 21 9.1
11 11.3 22 14.1
10.81 Average
Table 7-3:Average Hull Thickness
Source: Adapted from Seaforth, 2014
It was previously shown that the estimated thickness was 11.95 mm, which means that
the average thickness is less than the actual field measurements. This can be accounted for if an
actual variable at the shipwreck site is different than those used in the analysis, for example, a
higher salient level or current velocity would increase the corrosion rates.
Figure 7-4 is a demonstration piece that was prepared by the author to demonstrate the
differences in steel thickness that are shown in Table 7-3.
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Figure 7-4: Steel Demonstration Piece of Steel Thickness Measured on the Manolis L
Source: Author
7.3 Risk Factors
The risk factor for the Manolis Lis the highest rating, meaning that the likelihood of an
oil spill is high and the consequences will be "serious".
7.4 Calculation of the Risk Score
Table 7-5 shows the calculation of the risk score for theManolis L.
Risk FactorRisk Factor
WeightsRationale
Vessel type / tonnage 5 Manolis Ltonnage is 5,421
Volume of pollutants 5 522 cu-m recorded at time of loss
Distance from coast or a sensitive area 5 less than 1 kmEnvironmental conditions 15 all variables are applicable
Age and condition of shipwreck 5 Manolis Lsank in 1985
TOTAL SCORE: 35
Table 7-5: Calculation of the Risk Score for the Manolis LSource: Author
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The value of the risk score means that theManolis Lis assessed to be serious, whichmeans
that potentially very severe effects are expected. This is a top priority case and should receive an
immediate action plan and mitigation.
7.5 Recommendation for Appropriate Risk Mitigation Strategies
Based on the analysis, calculations, and oil remediation options currently available and
applicable, options D or E, as shown in Table 7-6, are the recommended risk mitigation
strategies.
Oil Remedial Option
Risk Identification A B C D E F
Risk score = Severe N N Y Y N
D pumping of pollutants from the shipwreck
E capping of the entire wreck
Table 7-6:Recommended Risk Mitigation Strategies for the Manolis L
Source: Author
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8.0 Conclusions
The purpose of this report was to develop a tool for quantitative risk and remedial options
assessment of potentially polluting shallow water shipwrecks in NL waters. This report
examined current shipwreck oil remedial options and determined which are best suited for
shallow water shipwrecks in NL waters. By utilizing the Manolis L shipwreck as a case study,
risk factors, such as the corrosion rates of steel and levels of consequences, were estimated and a
shipwreck risk and remedial options matrix developed that can aid in the prioritization of
remediation and environmental response options.
It was shown that the effects of oil spills from shipwrecks depend on numerous factors,
such as the type and amount of oil on board at the time of sinking, the characteristics of the
affected environment, the water temperature and depth, shipwreck location, the condition of the
ship at the time of sinking, and the length of time the wreck has been submerged. A quantitative
approach was developed for the subject region and wreck depth and location from shore that can
be used as a tool in the shipwreck mitigation process in setting priority levels to different
shipwrecks.
Current shipwreck oil remedial techniques and shipwreck management strategies were
investigated and their applicability to, and functionality in, the subject region were analyzed. Not
all of the current oil remediation options are applicable and were, therefore, removed from the
list of acceptable options.
Expanded further, a method was developed to perform a risk analysis that led to an
overall risk score that can be used in the decision-making process. An evaluation of which risks
to consider and how to prioritize among them was included in the risk evaluation steps along
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with a comparison of possible oil remediation options, which may provide support to the
decision-makers on benefits and limitations of possible risk treatment alternatives.
The case study investigated, the Manolis L, was evaluated using all of the analysis
methods as laid out in this report. This demonstrated the functionality of these methods as
applied to an actual shipwreck. The risk score was calculated, the level of consequences were
determined and a recommendation for an oil remediation option for this shipwreck was put forth.
9.0 Recommendations
Based on the information outlined in this report, the following set of recommendations
are encouraged:
Decision-makers in the shipwreck oil remediation process should consider the corrosion
rate of steel shipwrecks as part of a shipwreck risk matrix.
The creation of a rubric and matrix to analyze each oil remedial option to determine
which are best suited for shallow water shipwrecks in NL waters.
Alternatives to the current shallow water shipwreck oil remedial technologies should be
researched.
A database of potentially polluting shipwrecks in NL waters should be developed and
each ship analyzed for risk and consequences and prioritized for remediation, if needed.
The Canadian government should immediately remove the oil from theManolis L
shipwreck or cap the entire shipwreck as determined by the risk analysis of this report.
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References
Alcaro, L., Amato, E., Cabioch, F., Farchi, C., Gouriou, V., Wrubl, C. (2007) Development of
European guidelines for potentially polluting shipwrecks. D.G. Environment, Civil
Protection Unit, Institute of Marine Sciences (ISMAR).
CBC News. (2015, January 16). Manolis L a time bomb for more oil leaks, warn residents.
Retrieved October 1, 2015 from http://www.cbc.ca/news/canada/newfoundland-
labrador/manolis-l-a-time-bomb-for-more-oil-leaks-warn-residents-1.2911960
Colbourne, E. B. (2004). Decadal Changes in the Ocean Climate in Newfoundland and
Labrador Waters from the 1950s to the 1990s. 2004.J. Northw. Atl. Fish. Sci., 34: 43-61.
doi:10.2960/J.v34.m478
DET NORSKE VERITAS (DNV) (Ed.). (2007). DNV Hull Inspection Manual (Vol. MTP NO
864). Hvik: DET NORSKE VERITAS.
Emergencies Science and Technology Division, Environment Canada (2006).Bunker C fuel oil.
Retrieved October 7, 2015, from http://www.etc-
cte.ec.gc.ca/databases/oilproperties/pdf/web_bunker_c_fuel_oil.pdf
Dahl, Erik J. (2001).Naval Innovation: From Coal to Oil. Joint Forces QuarterlyVolume 27,
pp. 50-56. Institute for National Strategic Studies, Nation Defense University,
Washington, D.C.
-
7/25/2019 Manolis L - Kevin Strowbridge Report
49/51
INVESTIGATION OF OIL REMEDIATION OPTIONS Page 39 of 41
Grennan, D. (2010) What is the current state of the art for assessment, salvage and response
technologies?International Corrosion Workshop, Newport News, VA.
Kuroda, T., Takai, R., Kobayashi, Y., Tanaka, Y., & Hara, S. (2008). Corrosion rate of
shipwreck structural steels under the sea. OCEANS 2008 - MTS/IEEE Kobe Techno-
Ocean, 08(978-1-4244-2126-8).
Landquist, H., Hassellv, I., Rosn, L., Lindgren, J., & Dahllf, I. (2013). Evaluating the needs
of risk assessment methods of potentially polluting shipwrecks.Journal of Environmental
Management Vol 119 (2013), pp 85-92.
Landquist, H., Rosn, L., Lindhe, A., Norberg, T., Hassellv, I., Lindgren, J., & Dahllf, I.
(2014). A fault tree model to assess probability of contaminant discharge from
shipwrecks.Marine Pollution Bulletin, 88, 239-248.
MacLeod, Ian. 2010. Modeling Corrosion, Assessment of Complicating Factors Panel.
International Corrosion Workshop, Newport News, VA. October 2010.
Mazarakos, D.E., Andritsos, F., Kostopoulos, V. (2012). Recovery of oil-pollutant from
shipwrecks:DIFIS project, International Journal of Structural Integrity, Vol. 3 Iss: 3 pp.
285 - 319
Milwee, W. (1996).Modern marine salvage. Centreville Md.: Cornell Maritime Press.
-
7/25/2019 Manolis L - Kevin Strowbridge Report
50/51
INVESTIGATION OF OIL REMEDIATION OPTIONS Page 40 of 41
Pounder, C., & Woodyard, D. (2004). Pounder's marine diesel engines and gas turbines (8th
ed.). Oxford: Elsevier Butterworth Heinemann.
Rao, A., Outhouse, L., Gregory, D. (2009). Special marine areas in Newfoundland and
Labrador, areas of interest in our marine backyards. Canadian Parks and Wildlife
Society (CPAWS), Newfoundland and Labrador Chapter.
Rogowska J, Namienik J (2010) Environmental implications of oil spills from shipping
accidents. Rev Environ Contam Toxicol 206:95114
Seaforth Geosurveys Inc. (2014)ROV support operations report removal and reinstallation of
cofferdam, hull thickness measurements and HD video survey of the shipwreck M.V.
Manolis L, Blow Hard Rock, NL. Dartmouth, NS.
Symons, L., Michel, J., Delgado, J., Reich, D., Rench McCay, D., Chmidt Etkin, D., & Elton, D.
(2014). The Remediation of Underwater Legacy Environmental Threats (RULET) risk
assessment for potentially polluting shipwrecks in u.s. waters. 2014 International Oil
Spill Conference.
Symons, L., Michel, J., Delgado, J., Reich, D., McCay, D., Etkin, D., Helton, D. (2014) The
Remediation of Underwater Legacy Environmental Threats (RULET) Risk Assessment
for Potentially Polluting Shipwrecks in U.S. Waters, 2014 International Oil Spill
Conference, Abstract 299454
-
7/25/2019 Manolis L - Kevin Strowbridge Report
51/51
INVESTIGATION OF OIL REMEDIATION OPTIONS Page 41 of 41
Transport Canada, Investigation report into the circumstances attending the grounding,
abandonment and sinking of the Liberian vessel "Manolis L." in Notre Dame Bay,
Newfoundland on January 17, 1985, Ottawa: Marine Casualty Investigations, 1985