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Scientific basis for the Ice Regime System: discussion paper Timco, G. W.; Kubat, I.
TP 13916E
Scientific Basis for the Ice Regime System:
Discussion Paper
G.W. Timco and I. Kubat Canadian Hydraulics Centre National Research Council of Canada
Ottawa, Ont. K1A 0R6 Canada
Technical Report CHC-TR-002
ABSTRACT
The objective of this report is to provide a framework for discussion on the approach that the Transport Canada should take to implement a more scientifically-based approach to the Canadian Ice Regime System. This report begins with a short overview of the work that has been performed to put the Ice Regime System on a scientific basis. The results of discussions with the Stakeholders of the Ice Regime System are then presented. Four possible approaches are proposed for the implementation of the system, and the advantages and disadvantages of each approach are discussed.
TABLE OF CONTENTS ABSTRACT... 1 TABLE OF CONTENTS... 3 LIST OF FIGURES ... 4 LIST OF TABLES... 4 1.0 INTRODUCTION ... 5 2.0 BACKGROUND INFORMATION ... 6
2.1 The Zone-Date System ... 6
2.2 The Ice Regime System ... 6
2.3 The Seven Tasks ... 11
2.3.1 Task 1 - Safety-Related Issues... 13
2.3.2 Task 2 - Specific Problems with Corresponding Ice Conditions... 13
2.3.3 Task 3 – Adequacy of the AIRSS Definition of the Ice Numeral ... 14
2.3.4 Task 4 - Definition of Problem Ice and Operating Conditions... 14
2.3.5 Task 5 - Identification of Problem Ice ... 15
2.3.6 Task 6 - Detection of Problem Ice ... 15
2.3.7 Task 7 – An Approach for the Implementation of the AIRSS... 15
3.0 GENERAL DISCUSSION ... 16
3.1 Should there be an Ice Regime System?... 16
3.2 Discussions with Commercial Ship Owners/Operators... 16
3.3 Discussions with Canadian Coast Guard ... 17
3.4 Information on the IRS Supplied by Transport Canada ... 17
3.5 Key Factors in the Ice Regime System ... 18
4.0 METHODS OF IMPLEMENTING THE ICE REGIME SYSTEM ... 21
4.1 Existing Definition of Ice Numeral (AIRSS Approach)... 22
4.2 Adding Modifiers to Ice Numeral (Interaction Approach) ... 24
4.3 Integer Bonus to Ice Multiplier (Modified Approach) ... 26
4.4 Non-Integer Multipliers (Non-Integer Approach) ... 28
5.0 AUTHOR’S VIEWPOINT ... 29
5.1 General Discussion ... 29
5.2 The Modified Ice Regime System ... 30
6.0 RECOMMENDATIONS... 32
7.0 ACKNOWLEDGEMENTS... 33
Timco and Kubat CHC-TR-002 Page 4
LIST OF FIGURES
Figure 1: Map showing the regions of the Zones in the Zone-Date System... 8
Figure 2: Context diagram for the scienitfic basis for the Ice Regime System ... 13
Figure 3: Pie charts showing the values of the Ice Numeral for Events with Damage Severity (DS) ≥3, 1 or 2, and 0. The Ice Numeral was calculated using the ASPPR defintion. ... 23
Figure 4: Pie charts showing the values of the Ice Numeral for Events with Damage Severity (DS) ≥3, 1 or 2, and 0. The Ice Numeral was calculated using the Interaction Approach. ... 25
Figure 5: Pie charts showing the values of the Ice Numeral for Events with Damage Severity (DS) ≥ 3, 1 or 2, and 0. The Ice Numeral was calculated using the Modified Approach... 27
LIST OF TABLES Table 1: Zone-Date Table ... 7
Table 2: Table of the Ice Multipliers (IM) for the Ice Regime System ... 10
Table 3: Vessel Class for the Ice Regime System ... 11
Scientific Basis for the Ice Regime System:
Discussion Paper
1.0 INTRODUCTION
Transport Canada has asked the National Research Council of Canada to investigate a methodology to put the Arctic Ice Regime Shipping System (AIRSS) on a scientific basis. The NRC developed a 7-Task approach to do this (Timco et al. 1997). The work on the Tasks is now complete.
The objective of this report is to provide a framework for discussion on the approach that Transport Canada should take to implement a more scientifically-based system. It will not review in any detail the 7 Tasks. Instead, it will summarize the authors’ findings on the steps necessary to implement a more scientifically-based system.
Timco and Kubat CHC-TR-002 Page 6
2.0 BACKGROUND INFORMATION
2.1 The Zone-Date System
In 1972, the Canadian Government drafted the Arctic Shipping Pollution Prevention Regulations (ASPPR) to regulate navigation in Canadian waters north of 60°N latitude. These regulations include the Shipping Safety Control Zones (Figure 1), and the Date Table (Table 1), made under the Arctic Waters Pollution Prevention Act. Both of these are combined to form the “Zone/Date System” matrix that gives entry and exit dates for various ship types and classes. In this system, the ship types and classes, in descending order of ice capability are:
Arctic Class: 10, 8, 7, 6, 4, 3, 2, 1A, 1
Type Ships: A, B, C, D, E
The Arctic Class was the thickness in feet of level ice that the vessel had the power and strength to break. The “Zone-Date System” is based on the premise that nature consistently follows a regular pattern year after year. It is a rigid system with little room for exceptions.
Although the Zone-Date System has been used for a number of years, it does have a number of shortcomings:
1. The permission to proceed into a region and the regulatory control for not allowing entry into a region is based solely on historical ice data for any given vessel. It does not take into account the ice conditions at the time that the vessel wants to enter the region;
2. There has not been a recent update on the ice information in the Zone-Date system so the defined zones are not based on the more recent and complete ice information;
3. Even if the ice conditions are light outside the zone-date for a particular vessel, it is not straightforward for the vessel to get permission to enter the zone;
4. The classification of the vessels is based on the performance of the vessel (i.e. how many feet of ice it can break) and not on the structural safety of the vessel in various ice conditions. Since the Regulations are geared towards safety (and not performance) this is a serious flaw in the system.
2.2 The Ice Regime System
Transport Canada, in consultation with Stakeholders, has made extensive revisions to the Regulations through the introduction of the Ice regime System (ASPPR 1989; Canadian Gazette 1996; Equivalent Standards 1995; AIRSS 1996). The changes are designed to reduce the risk of structural damage in ships which could lead to the release of pollution into the environment, yet provide the necessary flexibility to Shipowners by making use of actual ice conditions, as seen by the Master to determine transit.
Timco and Kubat CHC-TR-002 Page 8
In this new system, an "Ice Regime", which is a region of generally consistent ice conditions, is defined at the time the vessel enters that specific geographic region, or it is defined in advance for planning and design purposes. The Arctic Ice Regime Shipping System (AIRSS) is based on a simple arithmetic calculation that produces an “Ice
Numeral” that combines the ice regime and the vessel’s ability to navigate safely in that
region. The Ice Numeral (IN) is based on the quantity of hazardous ice with respect to the ASPPR classification of the vessel (see Table 2). The Ice Numeral is calculated from
.... ] [ ] [ + + = CaxIMa CbxIMb IN [1] where IN = Ice Numeral
Ca = Concentration in tenths of ice type “a”
IMa = Ice Multiplier for ice type “a” and Ship Category (from Table 2)
The term on the right hand side of the equation (a, b, c, etc.) is repeated for as many ice types as may be present, including open water. The values of the Ice Multipliers are adjusted to take into account the decay or ridging of the ice by adding or subtracting a correction of 1 to the multiplier, respectively (see Table 2). The Ice Numeral is therefore unique to the particular ice regime and ship operating within its boundaries.
The vessel class is defined in terms of vessels that are designed to operate in severe ice conditions for both transit and icebreaking (Canadian Arctic Class - CAC class) as well as vessels designed to operate in more moderate first-year ice conditions (Type vessels). The classes were developed based on a “limiting” ice type, which were correlated to the World Meteorological Organization (WMO) classification for sea ice as given in Table 3 (ASPPR 1989).
The Ice Regime System determines whether or not a given vessel should proceed through that particular ice regime. If the Ice Numeral is negative, the ship is not allowed to proceed. However, if the Ice Numeral is zero or positive, the ship is allowed to proceed into the ice regime. Responsibility to plan the route, identify the ice, and carry out this numeric calculation rests with the Ice Navigator who could be the Master or Officer of the Watch. Due care and attention of the mariner, including avoidance of hazards, is vital to the successful application of the Ice Regime System. Authority by the Regulator (Pollution Prevention Officer) to direct ships in danger, or during an emergency, remains unchanged.
At the present time, there is only partial application of the Ice Regime System, exclusively outside of the “Zone-Date” System. That is, vessel traffic is regulated by the Zone-Date System, but is allowed to proceed into a (normally) restricted zone if the ice conditions are such that the Ice Regime System gives a positive Ice Numeral. For this, the vessel must have an Ice Navigator onboard and initially send an Ice Regime Routing Message to the CCG-NORDREG office in Iqaluit indicating a positive ice regime. Following the voyage, an After Action Report must be submitted to Transport Canada.
Timco and Kubat CHC -TR -002 Page 10 Table 2 :
Table of the Ice Multipliers (IM) for the Ice Regime System
T a b l e O f I c e M u l t i p l i e r s B y S h i p C a t e g o r y
AES / WMO I c e M u l t i p l i e r s for each S h i p C a t e g o r y
Ice Codes I c e T y p e s Type E Type D Type C Type B Type A CAC 4 CAC 3
7• or 9• Old / Multi-Year Ice... (MY) -4 -4 -4 -4 -4 -3 -1
8• Second Year Ice ... (SY) -4 -4 -4 -4 -3 -2 1
6 or 4• Thick First Year Ice ... (TFY) > 120 cm -3 -3 -3 -2 -1 1 2
1• Medium First Year Ice ... (MFY) 70-120 cm -2 -2 -2 -1 1 2 2
7 Thin First Year Ice ... (FY) 30-70 cm -1 -1 -1 1 2 2 2
9 Thin First Year Ice - 2nd Stage 50-70 cm
8 Thin First Year Ice - 1st Stage 30-50 cm -1 -1 1 1 2 2 2
3 or 5 Grey-White Ice... (GW) 15-30 cm -1 1 1 1 2 2 2 4 Grey Ice... (G) 10-15 cm 1 2 2 2 2 2 2 2 1 ð∆ °°°°
Nilas, Ice Rind
New Ice ... (N) Brash (ice fragments < 2 m across)
Bergy Water Open Water < 10 cm < 10 cm 2 “ “ “ “ 2 “ “ “ “ 2 “ “ “ “ 2 “ “ “ “ 2 “ “ “ “ 2 “ “ “ “ 2 “ “ “ “
Notes: Decayed Ice: For the following ice types: MY, SY, TFY, and MFY that are ‘decayed’, add 1 to the Ice Multiplier.
Ridged Ice: For floes of ice that are over 3/10ths ‘Ridged’ and in an overall concentration that is greater than 6/10ths, subtract 1 from the Ice Multiplier.
Table 3: Vessel Class for the Ice Regime System
CATEGORY OPERATING
ROLE ICE TYPE
CAC 1 Unrestricted Multiyear Ice CAC 2 Transit or controlled icebreaking Multiyear Ice CAC 3 Transit or controlled icebreaking Second Year Ice CAC 4 Transit or controlled icebreaking Thick First Year Ice Type A Transit Medium First Year Ice
Type B Transit Thin First Year Ice - 2nd Stage Type C Transit Thin First Year Ice - 1st Stage Type D Transit Grey-White Ice
Type E Transit Grey Ice
Over the years, Transport Canada has sponsored a considerable amount of research on the Ice Regime System through a series of dedicated shipboard observations. They have also sponsored several projects and Workshops related to the understanding of local hull loads on vessels in different ice conditions. Further, they have worked with the Canadian Ice Service to ensure that there is co-ordination between the two Organizations with respect to the Ice Regime System.
Transport Canada also produced a Users Assistance Package (1998), which provides information and a video on the Ice Regime System.
2.3 The Seven Tasks
Credibility of the Ice Regime System has wide implications, not only for ship safety and pollution prevention, but also in lowering ship insurance rates and predicting ship performance. Therefore, there is a definite need to establish a scientific basis for the system. To this end, Transport Canada approached the Canadian Hydraulics Centre of the National Research Council of Canada in Ottawa to assist them in developing a methodology for establishing a scientific basis for AIRSS. This led to a "road map" approach that is based on 7 Tasks (Timco and Frederking 1996; Timco et al. 1997).
Different approaches were looked at to put the system on a scientific basis. For a variety of reasons, it was decided that an empirical approach would provide the most confidence in establishing a scientific basis. That is, the approach is not based on first-principle calculations of potential ice damage. Instead, the approach makes use of the large number
Timco and Kubat CHC-TR-002 Page 12
of different vessels that have traveled through a wide range of ice and environmental conditions. It investigates the actual conditions that have caused vessel damage in ice.
There are many things to consider with the ice regime system. First, it is based on the Pollution Prevention Regulations and is, therefore, safety (not operational) oriented. Any suitable system must meet the needs of Transport Canada as the Regulator, but must not unduly penalize ship operators from operating in ice-covered waters. In developing a scientific basis, there are a number of key components that can be used as input into the scientific approach. Based on this analysis, Timco and Frederking (1996) prepared the Context Diagram for the scientific basis as shown in Figure 2. This Diagram presents a summary overview of the main factors driving this work. It is important to understand this diagram. It is the main driving force for the scientific basis.
In developing the methodology, a very straightforward approach was employed. The approach centred on asking and answering seven basic questions. Each question is a logical extension to the answer of the previous question. The basic questions are:
1. What problems can happen to a ship in ice?
2. What are specific examples of problems that have occurred that could be used for a deterministic development? i.e. specific case-histories that can be used to identify and understand the problems.
3. Would the current ice regime system have predicted these problems? 4. If not, how can the problem conditions be better defined?
5. Can the current ice detection methods identify the problem ice conditions?
6. If not, how can the ice detection systems be improved in a pragmatic manner to be able to detect the problem ice?
7. How can this information be communicated to the ship to implement the Ice Regime System?
These questions led to the following 7 Tasks:
1. Define Safety-Related Issues
2. Definition of Specific Problems with the Corresponding Ice Conditions 3. Assess the Adequacy of the AIRSS
4. Definition of Problem Ice and Operation Conditions 5. Identification of Problem Ice
6. Detection of Problem Ice
Figure 2: Context diagram for the scienitfic basis for the Ice Regime System
The author and his Colleagues have published a number of reports and papers describing the approach and the work that was done in each of the 7 Tasks (Timco and Frederking 1996; Timco et al. 1997, 1999; Timco and Morin 1997, 1998a, 1998b; Timco and Kubat 2000, 2001a, 2001b; Kubat and Timco 2001). The results are too lengthy to report here and only a brief sketch of the results of each Task will be presented here. Interested parties should consult the original reports for complete details.
2.3.1 Task 1 - Safety-Related Issues
This task reviewed historical data on the safety-related problems that a ship could encounter in ice. The review showed that a large number of vessels have been damaged by ice. The damage primarily relates to hull deformation or fractures due to impacts with ice, damage to propellers or steering gears, vessel immobilization due to pressured-ice conditions, and ice overtopping the deck and damaging critical elements. A complete listing of the damage descriptions can be found in Timco and Kubat (2000). The output of the task was a classification of safety-related issues and identification of a comprehensive set of data sources.
2.3.2 Task 2 - Specific Problems with Corresponding Ice Conditions
In this task, it was necessary to collect, in a very systematic manner, information on both damage Events and non-damage Events. In this case, an Event is described as ship transit through a known ice regime. The Event included all relevant information about the transit including the vessel characteristics, route, climate, ice conditions and resulting damage (or no damage). It was important to include both damage and non-damage events to
Timco and Kubat CHC-TR-002 Page 14
ensure that the analysis had a fair balance between the restrictions to limit damage (i.e. Regulators viewpoint) and the ability to travel through ice (Operators viewpoint).
The CHC developed a very comprehensive database that combines all of the key elements in a systematic manner (Timco and Morin 1997, 1998a, 1998b; Timco et al. 1999). Since the details of the database have been discussed extensively in these references, they will not be described here. For the present purposes it is important to understand that the database can be used to evaluate the influence of a number of different parameters in the Ice Regime System.
2.3.3 Task 3 – Adequacy of the AIRSS Definition of the Ice Numeral
It was possible to use the CHC database to determine if the definition for the Ice Numeral (IN) proposed in the AIRSS agrees with documented empirical data. An analysis was performed and it was found that although the definition provided a reasonable definition, there were several Events of ship damage that had a positive Ice Numeral, and a considerable number of Events with a negative Ice Numeral in which there was no damage. According to this analysis, the current definition of the Ice Numeral captures the general desired trend. However, the current definition misses several damage Events, and significantly restricts access in situations in which there was no resulting damage.
2.3.4 Task 4 - Definition of Problem Ice and Operating Conditions
In this task, the CHC database was used to investigate the relative influence of a number of factors not considered in the current definition of the Ice Numeral. This was done by using an “Interaction Approach” which takes into account factors such as vessel speed, experience of the Master, ice strength, visibility, etc. (see Timco and Kubat 2000, 2001b). This approach showed a significant improvement in the definition of the Ice Numeral. The methodology had 2 basic underlying principles driving it:
1. Ship Operators are rewarded when they use a high ice-strengthened vessel (CAC or Type A, B) operating with experienced Masters who proceed carefully through difficult ice and navigation conditions.
2. Ship Operators are severely penalized when they use lower class vessels (Type C and lower) and less experienced personnel.
Although this approach provided a significant improvement in the definition of the Ice Numeral, its application would be difficult since several factors must be taken into account. Nevertheless, it clearly showed that a significant improvement could be made if the appropriate factors were taken into account in the Ice Regime System.
2.3.5 Task 5 - Identification of Problem Ice
This task examined the ability of the Canadian Ice Service (CIS) and current ice detection systems to accurately predict the ice conditions. A comparison was made of CIS-predicted ice conditions with ground-truthed information (Timco and Kubat 2000; Kubat and Timco, 2001). Based on the data analysed in this Task, it appears that the CIS ice predictions usually present a reliable description of the actual ice conditions. Although the predictions were not exactly accurate, there was no observable bias in the predictions.
An analysis was also performed of the variability of ice regimes within a single egg code “region” of an ice chart. This analysis showed that, although the average conditions are correct, there could be considerable variability in the ice conditions within the region. Thus, the ice charts should not be solely used for calculating the Ice Numeral for tactical navigation. Continual on-board ice observations are an essential component for correct determination of the Ice Numeral.
2.3.6 Task 6 - Detection of Problem Ice
The intent of this Task was to examine, in a pragmatic way, improvements in ice identification methods that could be implemented if the results of Task 5 were poor. However, as noted above, the CIS predictions are quite reasonable and can be used in the IRS for strategic planning. Thus, there was no effort spent in this Task.
2.3.7 Task 7 – An Approach for the Implementation of the AIRSS The results of this Task are presented in the remainder of this report.
Timco and Kubat CHC-TR-002 Page 16
3.0 GENERAL DISCUSSION
Once the basic groundwork for the scientific basis was in place, the remaining Task was to develop an approach to implement it. During the course of this work the author had numerous discussions with several of the key Stakeholders. These discussions were invaluable. They shaped the thoughts that follow.
In developing Task 7, it is important to revisit the Context Diagram that is driving the scientific basis (Figure 2). The work done to date basically integrates all of the items in the red boxes on the diagram. Now, the remaining Task is to develop a plan for implementation that is acceptable to Transport Canada and the Ship Operators, while still maintaining the scientific basis. It should be stated up-front that the author is not a Stakeholder in the Ice Regime System. The author’s work has been to try to facilitate the scientific basis.
3.1 Should there be an Ice Regime System?
A fundamental question arises with respect to the Ice Regime System. It has been used outside the Zone-Date System for several years now so there is a good amount of experience with it. There was a very strong opinion that the concept of the Ice Regime System was a good one. There are several advantages of the Ice Regime System (IRS) over the Zone-Date System (ZDS):
1. The analysis of the available information for the scientific basis clearly shows that the Ice Regime System does provide a good approach for identifying dangerous ice conditions;
2. There has been a very significant advance in the quality and availability of the ice information over the past several years. The IRS approach makes direct use of this information whereas the ZDS does not use it directly;
3. Some vessels have very sophisticated onboard ice information systems (e.g. IceNav) that provide near real-time ice information that can be used for both strategic and tactical operations;
4. There has been a much better understanding of the process of hull loading by ice and the attendant hull loads. This information has been integrated into the Ice Regime System;
5. There has been a great deal of experience gained with the IRS that is both shipboard experience and documented experience. This makes it possible to improve the IRS.
These are very strong and compelling reasons for the use of the Ice Regime System compared to the Zone-Date System.
3.2 Discussions with Commercial Ship Owners/Operators
During discussions with several of the Ship Owners/Operators, it was clear that there was a great deal of both confusion and mistrust of the Ice Regime System. Some of the complaints included:
• The definition of the Ice Numeral is incorrect – there have been numerous voyages with a negative IN with no damage;
• Learning the system is confusing and difficult;
• Implementing it in real-time is not possible;
• The system does not take into account a number of the key features (such as vessel speed and floe size);
• Experienced Masters do not have to calculate an IN – they know when they are in a potentially dangerous situation;
• Most accidents occur due to undetected hazards;
• The definition of an ice regime is ambiguous. There could be hundreds on each voyage;
• Multi ice regimes lead to complexity since there is no need to calculate the IN for all regimes;
• They were comfortable with the Zone-Date System and could use it for their long-term planning.
It was also clear that there was a general mistrust of the Ice Regime System, since many felt that it would give “Ottawa” greater control over their shipping. Some even felt this could occur in almost a real-time situation.
In spite of this, the Ice regime System is being used by several of the Operators outside of the Zone-Date System with very good success.
3.3 Discussions with Canadian Coast Guard
The Canadian Coast Guard has not had much experience with the Ice Regime System. Over the past year or so, however, there has been a move to educate the CCG on the System and have them use it. Discussions with the CCG indicated:
1. They found it difficult and confusing to use;
2. They did not find a good correlation between the Ice Numeral and the potential degree of danger associated with the ice regime;
3. There were some issues related to the regulatory control of shipping due to the IRS.
In discussions with the CCG, it was apparent that they had not received proper training on the System and this could explain a large part of the confusion and negativism on their part. They were, however, quite willing to pursue the training aspects and continue to evaluate the Ice Regime System if it was done in a co-ordinated and comprehensive manner.
3.4 Information on the IRS Supplied by Transport Canada
In light of the comments by both the commercial operators and the CCG, the author critically reviewed the information supplied by Transport Canada on the Ice Regime
Timco and Kubat CHC-TR-002 Page 18
System. This included the original report on the ASPPR (ASPPR 1989), as well as the Equivalent Standards (1995), the Arctic Ice Regime Shipping System Standards (AIRSS 1996) and the more recent User Assistance Package (Transport Canada UAP, 1998).
Although the information on the IRS is contained in these reports, they are, in the author’s view, very inadequate to be used as a training tool for the Ice Regime System. A few examples:
• The reports and information relate everything directly to the Regulations, and this makes the whole system appear to be very bureaucratic and unworkable.
• The reports and the User Assistance Package (UAP) do not teach the basic concepts of the Ice Regime System in a straightforward manner. For example, the definition of an ice regime is not presented until page 9 of the UAP;
• The UAP does not define the information in the Canadian Ice Service “Egg Code”, yet it is used to illustrate examples of the calculation of the Ice Numeral;
• There are inconsistencies in the definition of the Ice Numeral. For example, there was no added bonus of +1 to the Ice Multiplier for decay of multi-year ice in the original ASPPR (1989) document, but there is a bonus in the AIRSS document.
• There was criticism of the software in the UAP. It did not work properly and often “crashed” the computer.
3.5 Key Factors in the Ice Regime System
The author discussed the factors that were identified in the “Interaction Approach” (Timco and Kubat 2001a, 2001b) with several of the Stakeholders. Some of the key comments follow:
Vessel Class (currently considered in the IRS)
• Essential component to consider
• Very difficult to incorporate since no ships have been built to the CASPPR class
• There can be discussions (i.e. negotiations) with Operators on the Ice Multipliers for specific ships
• Some vessels are severely downgraded due to only 1 or 2 features that do not meet the class (e.g. Russian Icebreakers)
• There can be some hesitancy to use the new Polar Code regulations since the technology can chase away the (conservative) shipping industry
• More substantiation of risk levels is required, especially for Type vessels. Ice Concentration (currently considered in the IRS)
• Essential component to consider
• Not a unique quantity (i.e. different concentrations might be estimated by two different people for the same ice regime)
Ice Thickness (currently considered in the IRS)
• Ice type boundaries can make a big difference in the Ice Numeral, especially for Type vessels, but difficult to sub-divide it further
• Ice roughness is also important to consider Summer Conditions (currently not considered in the IRS)
• Important component to consider
• Related to strength of ice, visibility and strength (brittleness) of ship steel
• More attention should be paid to ice strength, especially for multi-year ice Decay (currently considered in the IRS)
• Confusion and non-clarity on the definition of decay
• Surface drainage information important to Operators Ridging (currently considered in the IRS)
• Taken into account in a reasonable manner with the existing system
• More effort should be directed towards quantifying this aspect – it gives an indication of the thickness of the consolidated layer
Presence of Multi-year Ice (currently considered in the IRS)
• Not clear why the Ice Multiplier for multi-year ice is the same of all Type vessels, i.e. why is –4 for both a Type A and Type E vessel? [Author’s note: The analysis of vessel damage by the authors clearly showed that a large number of damage Events are caused by multi-year ice]
• Multi-year ice in the summer months can be either very strong or very weak and it is not possible to detect which state the ice is in. Therefore it must always be treated with caution
Ships under Escort (currently indirectly considered in the IRS)
• Difficult to consider
• Important that both the Escort vessel and the escorted vessel understand the Ice Regime System
• This can effect floe size which is not reflected in the Ice Numeral; i.e. the ice concentration and thickness can be the same, but the smaller floe size does not have the weight to cause damage
Visibility (currently not considered in the IRS)
• Important component to consider
• Due caution of Mariner
Timco and Kubat CHC-TR-002 Page 20
Vessel Speed (currently not considered in the IRS)
• Important component to consider
• Could eventually develop a relationship to make the Ice Numeral a function of vessel speed for each vessel class.
Experience of Master or Ice Navigator (currently not considered in the IRS)
• Important aspect to include
• Ice Navigators should have minimum 4 or 5 trips to the Arctic under the supervision of an experienced Ice Navigator before they should be allowed to go alone
• Regulations should be all encompassing for Ice Navigator requirements
• IMD/MUN developed a course syllabus for Ice Navigators about 5 years ago, but this was never implemented
• Critically important factor – it can integrate a number of the other factors Maneuverability of Vessel (currently not considered in the IRS)
• Important factor but difficult to incorporate explicitly
• Depends upon the experience of the Master
• Can influence the ice regimes since a more maneuverable vessel can more readily avoid multi-year ice and large ice floes
Navigational (ice information) Equipment (currently not considered in the IRS)
• Current regulations for this non-existent, but very important aspect (most damage occurs due to lack of detectability of dangerous ice)
• Should be part of the AIRSS System Floe Size (currently not considered in the IRS)
• Consider using due caution
• Can alter the ice regime considerably since it can affect the manoeuvrability of the vessel
• Smaller ice floes do not have the same weight to damage a vessel Bergy Bits (currently not considered in the IRS)
• Can’t be considered in the Regulations since the concentration is not specified on the ice charts
• Very important to consider since they can cause considerable damage [Author’s note: Their strength is comparable to multi-year ice].
• Could include this aspect by incorporating the “bergy water” regions of the CIS Ice Charts
4.0 METHODS OF IMPLEMENTING THE ICE REGIME SYSTEM
What is the best way to proceed to revise, improve and implement the Ice Regime System? A number of suggestions were put forward during the discussions with the various Stakeholders. The author has consolidated these into four possible approaches:1. Existing Definition of Ice Numeral 2. Adding Modifiers to Ice Numeral 3. Integer Bonus to Ice Multiplier 4. Non-Integer Multipliers
Each of these approaches will be discussed in the following sections. It should be noted that the approaches are put forward for discussion purposes by all Stakeholders.
Timco and Kubat CHC-TR-002 Page 22
4.1 Existing Definition of Ice Numeral (AIRSS Approach)
Description – The existing definition of the Ice Numeral using the existing AIRSS Table of Multipliers with the existing modifications for decay and ridging.
Approach – The existing Ice Regime System would be used in its present form.
The Advantages of this approach are:
1. System has been used for several years – familiarity 2. Relatively simple to use
3. Can be easily indicated on CIS Ice Charts (i.e. minimum class entry into an egg code region)
The Disadvantages of this approach are:
1. Reasonable, but not good fit to empirical data 2. Does not cover all of the important parameters 3. No speed factor
4. Table of Multipliers is confusing to some people
5. Table of Multipliers is inconsistent (e.g. same Multiplier for multi-year ice for Class E and Class A vessels).
An analysis of the data in the CHC/NRC Ice Regimes Database was done to investigate the suitability of this definition. Figure 3 shows the results in a pie chart format. In this case, the data has been broken down into 3 different Damage Severity (DS) situations:
1. Damage Severity where DS≥3, which could cause potential pollution (Potential Pollution Damage – PPD)
2. Damage Severity where DS = 1 or 2 in which there was some damage to the vessel, but no breach of the hull
3. Damage Severity where DS = 0 where there was no damage.
For an ideal Ice Regime System, all of the damage with DS ≥ 3 should be negative (i.e. the top pie chart should be all red), and all non-damage Events should have DS =0 (i.e. all of the bottom pie chart should be green). This is clearly not the situation with the current AIRSS definition of the Ice Numeral.
In this case, although the current AIRSS definition “captured” 84% of the PPD damage Events, it missed 16%. Moreover, there were 18% of the non-damage Events (DS = 0) which had a negative Ice Numeral yet the vessel did not sustain any damage.
Positive IN
16%
Negative IN
84%
Positive IN46% Negative IN 54%Positive IN
82%
Negative IN
18%
Figure 3: Pie charts showing the values of the Ice Numeral for Events with
Damage Severity (DS) ≥3, 1 or 2, and 0. The Ice Numeral was calculated
Timco and Kubat CHC-TR-002 Page 24 4.2 Adding Modifiers to Ice Numeral (Interaction Approach)
Description – Use a (revised) Table of Multipliers and add or subtract to the calculated Ice Numeral to modify for speed, visibility, experience, etc.
Approach – The existing Ice Regime System is used to calculate an Ice Numeral. Then, the IN could be increased or decreased by adding pre-defined quantities for each of the important factors (i.e. add +5 if vessel speed is less than 3 knots; subtract –3 if Type E vessel and multi-year ice is present, etc.). The details of the amount to be added or subtracted would be based on the best fit to the CHC/NRC database and the experience of the Stakeholders. This approach would be similar to that discussed by Timco and Kubat (2001a, 2001b) for optimizing the data fit to the database. It is based on the Interaction Approach discussed by Timco and Kubat.
The Advantages of this approach are: 1. Significantly more accurate system
2. Can take into account virtually all factors including speed
The Disadvantages of this approach are:
1. Very difficult and time-consuming to use
2. Each ice regime would require detailed calculations
3. Would require a computer program for calculations (therefore more costly to implement and/or not usable on all vessels)
4. Disagreement on the amount of adjustment for each factor
5. Could not be used for route planning (e.g. visibility would modify the IN, etc.).
Figure 4 shows a pie chart distribution of the data based on this definition. It is a significant improvement over the existing AIRSS definition. In this case more of the PPD damage Events have a negative Ice Numeral. More strikingly, the number of negative IN Events with no damage is significantly decreased. With this approach, the number of false negative Events decreased from 18% to 6%. Clearly, this is a much more accurate approach.
Positive IN
13%
Negative IN
87%
Positive IN 59% Negative IN41%Positive IN
94%
Negative IN
6%
Figure 4: Pie charts showing the values of the Ice Numeral for Events with
Damage Severity (DS) ≥3, 1 or 2, and 0. The Ice Numeral was calculated
Timco and Kubat CHC-TR-002 Page 26 4.3 Integer Bonus to Ice Multiplier (Modified Approach)
Description - Use the existing Table of Multipliers and give a bonus of +1 to the Ice Multipliers if a vessel has three specific features; viz, Master with a certain number of years of experience, very good ice detection equipment, and summer (low strength) ice conditions.
Approach – The existing Ice Regime System approach would be used. Ship Operators could increase the Ice Multiplier for first-year ice if the vessel meets three additional criteria: (1) the Master or Ice Navigator has more than “x” years of Arctic experience, (2) there is complete ice detection/navigation equipment onboard and used by experienced personnel, and (3) the ice has low strength due to summer conditions. In this case, the summer condition criterion would replace the decay bonus and be based on a predefined analysis as advanced by Timco et al. (2001).
The Advantages of this approach are:
1. Familiarity since very similar to the existing IRS
2. Emphasis on experienced, well equipped vessels, i.e. more safety oriented 3. Would allow more access for better-equipped vessels
4. Better fit to the empirical data.
The Disadvantages of this approach are:
1. Vessel would require all of the necessary factors to get a bonus
2. Possible disagreement on the amount of experience and equipment that would be required for the bonus. This would have to be defined by Transport Canada
3. Would not take into account many of the other important factors (e.g. vessel speed, floe size, etc.) in an explicit manner.
An analysis was performed of the data using this approach and making reasonable assumptions regarding the dates for the summer bonus. The analysis in this case was somewhat subjective and the data that was influenced by this approach was quite limited because of this. Figure 5 shows the results in pie chart format. In this case, there is no change for the DS ≥ 3, or DS = 1 or 2, but there is some improvement for the DS = 0 data. In this case, the number of false-negative Events decreased to 16% compared to 18% with the AIRSS definition.
Positive IN 46% Negative IN 54%
Positive IN
16%
Negative IN
84%
Positive IN
84%
Negative IN
16%
Figure 5: Pie charts showing the values of the Ice Numeral for Events with
Damage Severity (DS) ≥ 3, 1 or 2, and 0. The Ice Numeral was
calculated using the Modified Approach.
Timco and Kubat CHC-TR-002 Page 28
4.4 Non-Integer Multipliers (Non-Integer Approach)
Description - Each vessel would be given a unique set of Multipliers based on the vessel class, experience, ice navigation equipment, time of year (i.e. ice strength, decay, etc.), vessel speed, …. This would be done when the vessel crosses north of 60° N latitude, and would be a (non-integer) bonus on the Ice Multipliers for each identified factor.
Approach – Every time a vessel crosses north of 60°N latitude, they register with NORDREG and provide standard details on the vessel including the Master, Ice Navigator, ice navigation equipment onboard, etc. NORDREG would evaluate this and provide a set of Ice Multipliers for the vessel (an IM for ice below the vessel limit ice type and an IM for ice above the limit ice type). This would be done using a pre-designed system for the defined factors. The Ice Multipliers would be non-integer and reflect the capability of the vessel, the crew, the time of year (i.e. ice strength, etc).
The Advantages of this approach are: 1. Very accurate system
2. Would encourage Ship Owners to improve safety items
3. The approach and application would be similar to the existing system except that non-integer Ice Multipliers would be used
4. Each Master would not be required to know the details of calculating the Ice Multipliers – This would be set-up in an automated way at NORDREG
5. Can readily incorporate changes from any international harmonization initiatives.
The Disadvantages of this approach are:
1. Considerably more work for Canadian Government 2. Initially could be confusing to the Ship Owners & Masters 3. Possible disagreement on the bonus amount for each factor.
An analysis of this approach is not possible until the modifiers for the Ice Multipliers have been established. However, it is expected that the results would be very similar to the Interaction Approach.
5.0 AUTHOR’S VIEWPOINT
5.1 General Discussion
The direction to take to put the Ice Regime System on a scientific basis is not straightforward. Compromises will have to be made.
Maintaining the status quo for the Ice Regime System (Approach #1) has several disadvantages and should not be considered. The most serious flaw is that it does not accurately reflect the empirical data for shipping in the Arctic. The present approach did not capture a number of the damage Events, and it seriously restricts navigation that has been shown to be safe (i.e. with no damage), yet has a negative Ice Numeral. Therefore if this approach is adopted, both the Regulators and the Operators will find frustration with the system.
From a scientific point-of-view, the best approach to take is either the Interaction Approach (adding modifiers to Ice Numeral) or the Non-Integer Approach (non-integer Multipliers). Both of these could be tailored to the empirical data to give the optimum fit for a scientifically-based system. However, both of the approaches would be very difficult and frustrating to implement.
From a practical point-of-view, the best approach to take is Modified Approach (integer bonus to the Ice Multipliers). This approach emphasizes safety aspects and rewards vessels with good experience and ice detection/navigation equipment. These factors were found to be the essential points in the scientific analysis of Timco and Kubat (2000, 2001b). In their analysis, they developed two basic underlying principles that gave the optimum fit to the empirical data:
1. Ship Operators are rewarded when they use a high ice-strengthened vessel (CAC or Type A, B) operating with experienced Masters who proceed carefully through difficult ice and navigation conditions.
2. Ship Operators are severely penalized when they use low ice class vessels and less experienced personnel.
These factors would be incorporated into the Modified Approach. In this case, several of the key factors such as speed, vessel manoeuvrability, floe size, etc. would not be taken into account explicitly. Instead, it would be implicitly taken into account in the experience of the Master or Ice Navigator. This would provide more flexibility for the Operators while maintaining the basic structure of the Ice Regime System. It should also provide the necessary framework for minimizing damage Events that could lead to pollution. Further, this approach would maintain the general simplicity of the current approach to the Ice Regime System. This approach combines the simplicity of the existing system with the improvement fundamentals driven by the scientific analysis. The difficult aspect of this approach relates to the definition of the experience level of the Master, and defining the acceptable level of ice detection/navigation equipment for the bonus integer. These aspects should not be insurmountable.
Timco and Kubat CHC-TR-002 Page 30
Based on this discussion and analysis, the author recommends that Transport Canada should actively investigate implementing Approach #3 for the Ice Regime System.
5.2 The Modified Ice Regime System
The Modified Ice Regime System would take the following form:
The Ice Numeral (IN) is based on the quantity of hazardous ice with respect to the classification of the vessel, and calculated using:
.... ] [ ] [ + + = CaxIMa CbxIMb IN [2] where IN = Ice Numeral
Ca = Concentration in tenths of ice type “a”
IMa = Ice Multiplier for ice type “a” and Ship Category
The term on the right hand side of the equation (a, b, c, etc.) is repeated for as many ice types as may be present, including open water. Table 4 lists the revised Table of Multipliers. In this table, the changes from the current Ice Multiplier table are indicated with yellow shading. There are 2 significant changes from the existing system:
1. The Ice Multipliers for multi-year and second-year ice are increased by 1 for all of the lower class vessels (Type E, D and C)1.
2. A Summer Bonus replaces the decayed ice modification. This Bonus would add +1 to the Ice Multipliers for first-year ice for vessels Type B and higher (indicated in the Red box). It would be given if:
1) There are low strength ice conditions2;
2) The Master or Ice Navigator has a minimum 4 years of experience in the Arctic; and
3) The vessel has suitable instrumentation and equipment for identifying the ice conditions. This could be a marine radar and downlink capability for receiving the CIS information directly.
1
This was done in response to the significant damage events that occur with the lower class vessels and multi-year ice (Timco and Kubat, 2000).
2
Timco et al (2001) have shown that the criterion for defining low strength ice can be based on the mean daily air temperature. An analysis has shown that the strength of the first-year sea ice is approximately 10% of the mid-winter strength once the mean daily air temperature has been above 0°C for 1 month. A similar criterion is being developed for the autumn (growth) season. There are plans to include these dates on the CIS Ice Charts.
Table 4: Table of Multipliers for the Modified Ice Regime System
Ice Multipliers for each Vessel Category
Type CAC
E D C B A 4 3
Old / Multi-Year Ice -5 -5 -5 -4 -4 -3 -1
Second-Year Ice -5 -5 -5 -4 -3 -2 1
Thick First-Year Ice -3 -3 -3 -2 -1 1 2 Medium First-Year Ice -2 -2 -2 -1 1 2 2 Thin First-Year Ice - 2nd Stage -1 -1 -1 1 2 2 2
Thin First-Year Ice - 1st Stage -1 -1 1 2 2 2 2
Grey-White Ice -1 1 1 2 2 2 2
Grey Ice 1 2 2 2 2 2 2
Nilas, Ice Rind 2 2 2 2 2 2 2 New Ice 2 2 2 2 2 2 2
Brash 2 2 2 2 2 2 2
Open Water 2 2 2 2 2 2 2
Ice Types
Ridged Ice: For floes that are 3/10th ridged and in overall concentration that is greater than 6/10s, subtract 1 from the
Ice Multiplier
Summer Conditions:For vessels that meet the Summer Condition requiremetns, add +1 to the Ice Mulitpiers for first-year ice
Timco and Kubat CHC-TR-002 Page 32
6.0 RECOMMENDATIONS
To move forward on the implementation of the Ice Regime System, the author recommends the following:
1. All Stakeholders – Transport Canada, Ship Owners/Operators, Canadian Coast Guard - must initially reach an agreement in principle that the Ice Regime System has definite merit and should be part of the Regulations;
2. All Stakeholders must have input into the decision of the best approach to define the Ice Numeral and implement the System. This approach must give the Regulators sufficient confidence that safety aspects are considered, whilst giving the Operators the necessary flexibility to operate their business. Once all Stakeholders have put forward their input, Transport Canada as the Regulator should decide and implement the best approach;
3. All Stakeholders must actively play a role in improving the Ice Regime System. This includes proving continual quantitative feedback on the use of the IRS, and advising on the relative importance of the key parameters affecting the Ice Numeral;
4. Transport Canada should develop an improved approach for educating people on the Ice Regime System. This approach should be directed towards helping people (1) understand the basic concept of the Ice Regime System, (2) identifying ice regimes, (3) calculating Ice Numerals for a variety of situations, and (4) using the various ice navigation information systems for supporting the Ice Regime System.
If these recommendations were followed by Transport Canada, the Ice Regime System would become an extremely useful and accurate method for minimizing the potential for pollution due to shipping in the Arctic.
7.0 ACKNOWLEDGEMENTS
The authors would like to thank a number of individuals for helpful comments and discussions including Glenda Cameron, Capt. Doug Camsel, Capt. John Cowan, Bob Frederking, Bob Gorman, David Jackson, Tim Keane, Andrew Kendrick, Tom Paterson, Victor Santos-Pedro, Peter Timonin, Georges Tousignant, Dugald Wells, Robert Wolfe, Brian Wright, and Tom Zagon.
8.0 REFERENCES
Equivalent Standards for the Construction of the Arctic Class Ships, 1995. Transport Canada Report TP-12260, Ottawa, Ont., Canada.
AIRSS 1996. Arctic Ice Regime Shipping System (AIRSS) Standards, Transport Canada, June 1996, TP 12259E, Ottawa. Ont., Canada.
ASPPR, 1989. Proposals for the Revision of the Arctic Shipping Pollution Prevention Regulations. Transport Canada Report TP 9981, Ottawa. Ont., Canada.
Canadian Gazette, 1996. Regulations Amending the Arctic Shipping Pollution Prevention Regulations. p 1729, Ottawa, Canada.
Kubat, I. and Timco, G.W. 2001. Ground-Truthing of Ice Conditions Predicted by the Canadian Ice Service. Proceedings 16th International Conference on Port and Ocean Engineering under Arctic Conditions, POAC’01, pp 1071-1080, Ottawa, Canada.
Timco, G.W. and Frederking, R.M.W. 1996. A Methodology for Developing a Scientific Basis for the Ice Regime System. National Research Council of Canada Report HYD-TR-009, TP-12789E, Ottawa, Canada.
Timco, G.W., Frederking, R.M.W. and Santos-Pedro, V.M. 1997, A Methodology for Developing a Scientific Basis for the Ice Regime System. Proceedings ISOPE’97, Vol II, pp 498-503, Honolulu, USA.
Timco, G.W. and Morin, I. 1997. Canadian Ice Regime System Database. National Research Council of Canada Report HYD-TR-024, TP 13003E, Ottawa, Canada.
Timco, G.W. and Morin, I. 1998a. Scientific Basis for Ice Regime System: March 1998 Update. National Research Council of Canada Report HYD-CTR-047, Ottawa, Canada.
Timco, G.W. and Morin, I. 1998b. Canadian Ice Regime System Database. Proceedings ISOPE’98, Vol. II, pp 586-591, Montreal, PQ, Canada.
Timco and Kubat CHC-TR-002 Page 34
Timco, G.W., Skabova, I. and Morin, I. 1999. Scientific Basis for Ice Regime System: March 1999 Update. National Research Council of Canada Report HYD-CTR-072, Ottawa, Canada.
Timco, G.W. and Kubat, I. 2000. Scientific Basis for the Ice Regime System: March 2000 Update. CHC/NRC Report HYD-TR-048, TP 1357E, Ottawa, ON, Canada.
Timco, G.W. and Kubat, I. 2001a. Scientific Basis for the Ice Regime System: March 2001 Update. CHC/NRC Report HYD-TR-061, TP-13405, Ottawa, ON, Canada.
Timco, G.W. and Kubat, I. 2001b. Canadian Ice Regime System: Improvements Using an Interaction Approach. Proceedings 16th International Conference on Port and Ocean Engineering under Arctic Conditions, POAC’01, pp 769-778, Ottawa, Canada.
Transport Canada UAP. 1998. User Assistance Package for the implementation of the Canada’s Arctic Ice regime Shipping System (AIRSS). Transport Canada Report and Video, TP12819, Ottawa, Ont., Canada.
PUBLICATION DATA FORM - FORMULE DE DONNÉES SUR LA PUBLICATION
1. Transport Canada Publication No. No
de la publication de Transports Canada
TP 13916E
2. Project No. - No
de l’étude 3. Recipients Catalogue No. No
de catalogue du destinataire
4. Title and Subtitle - Titre et sous-titre
Scientific Basis for the Ice Regime System: Discussion Paper
5. Publication Date - Date de la publication
March 2002
6. Performing Organization Document No. No du document de l’organisme
CHC-TR-002
7. Author(s) - Auteur(s)
G.W. Timco and I. Kubat
8. Transport Canada File No. No de dossier de Transports Canada
9. Performing Organization Name and Address - Nom et adresse de l’organisme exécutant
Canadian Hydraulics Centre
National Research Council of Canada Ottawa, Ont. K1A 0R6
10. DSS File No. - No de dossier - ASC
11. DSS or Transport Canada Contract No. No de contrat - ASC ou Transports Canada
12. Sponsoring Agency Name and Address - Nom et adresse de l’organisme parrain
Transport Canada Marine Safety 330 Sparks St.
Ottawa, Ont. K1A 0N8
13. Type of Publication and Period Covered Genre de publication et période visée
Technical Report
14. Sponsoring Agency Code -Code de l’roganisme parrain
15. Supplementary Notes - Remarques additionelles 16. Project Officer - Agent de projet
V.M. Santos-Pedro
17. Abstract – Résumé
The objective of this report is to provide a framework for discussion on the approach that the Transport Canada should take to implement a more scientifically-based approach to the Canadian Ice Regime System. This report begins with a short overview of the work that has been performed to put the Ice Regime System on a scientific basis. The results of discussions with the Stakeholders of the Ice Regime System are then presented. Four possible approaches are proposed for the implementation of the system, and the advantages and disadvantages of each approach are discussed.
18. Keywords - Mots-clés
AIRSS, Ice Numerals, ASPPR, Regulations
19. Distribution Statement - Diffusion
20. Security Classification (of this publication) Classification de sécurité
(de cette publication)
Unclassified
21. Security Classification (of this page) Classification de sécurité (de cette page)
Unclassified
22. Declassification (date)
Déclassification (date) 23. No. of Pages Nombre de pages
34
