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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INVESTIGATION OF OIL REMEDIATION OPTIONS Page ii

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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INVESTIGATION OF OIL REMEDIATION OPTIONS Page iii

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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INVESTIGATION OF OIL REMEDIATION OPTIONS Page iv

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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v

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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INVESTIGATION OF OIL REMEDIATION OPTIONS Page vi

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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vii

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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INVESTIGATION OF OIL REMEDIATION OPTIONS Page viii of 2

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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INVESTIGATION OF OIL REMEDIATION OPTIONS Page 1 of 41

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


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


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


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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