ITS 2016 Boston - Tugconomy paper

Day 1 Paper 8

BOSTON Organised by The ABR Company Ltd

Tugconomy: A New Approach to Value-Based Towage Marinus Jansen (speaker/author), Rotortug BV, the Netherlands

SYNOPSIS

‘Tugconomy’ is a concept that describes a structured value-for-money framework for determining performance space requirements for greenfield marine operations. Tugconomy aims to exclude biases, both positive and negative, in order to provide operators and other stakeholders in greenfield developments with a transparent development cycle. Studying different tug concepts in competition during the development cycle, and including non-normal operations in the process, will provide all stakeholders with a consensus on the ALARP towage solution for their prospective projects.

INTRODUCTION

associated with such risk levels involves multiple parties – and just as many disciplines.

Floating LNG (FLNG) projects rank among the most complex and prestigious marine greenfield operations worldwide. Seven FLNG import/export terminals are currently approved and under construction globally, with an additional six approved (but not yet under construction) on the US East coast and Gulf of Mexico. Twenty-two additional export-only terminals are in various stages of development. LNG is rapidly developing into an energy commodity independent from offshore oil. Even if a strong correlation between oil and gas prices persists and only 20 per cent of these projects prove to be economically feasible, this would mean eight to 10 LNG terminal projects going ahead in the foreseeable future, in the US and Canada alone.

The design process is essentially a social undertaking, where multiple parties, pooling their cumulative knowledge and experience, engage in an engineering process. For example, port developers generally have the means and software capability to optimise aspects such as bathymetry in port lay-outs, yet developing towage services is often considered at the back end of such engineering studies. Including towage services development at a late stage tends to limit design solutions to the scope of normal operations only, while tug design concepts are over-influenced by the past experiences – both positive and negative – of involved parties.

Hazard and risk assessments on greenfield marine LNG operations demand a structured front-end development cycle, including assessment of towage services. Such development cycles should preferably be conducted in a transparent manner and provide stakeholders with multiple options and towage solutions. Extending the development cycle to include non-normal operations, as well as studying different tug concepts in competition, truly provides an ‘as low as reasonable and practicable’ (ALARP) towage service.

Including the development of towage services at an early stage enables synergies between infrastructure and towage service development. Efficient application of available knowledge and resources at the early development phase, defining the required performance space, releases resources in the later stage to include non-normal operations and create non-biased comparative studies between tug concepts to find the ALARP towage solution.

PERFORMANCE MATTERS

Developing a towage service at an FLNG greenfield site is usually considered to come within the scope of such an operation’s hazard and risk assessment. Development teams for greenfield operations generally aim at a pre-defined service level, with ALARP risk levels. Evaluating the required performance space1 and bollard pull (as a subset of the performance space)

Tugboats are a tool at the pilot’s disposal. Pilots require a tug to provide a vector within a reasonable framework of time or response. How much of a force vector, or what is considered a reasonable timeframe, is largely a subjective matter. Industry consensus suggests a faster vector response corresponds with a reduced vector 1

requirement, but quantifying one or the other mainly relates to what technology is available and whether it meets the functional requirements, rather than the other way around: what is the functional requirement and what technologies are available to meet this?

parameter: bollard pull. Tug deployment can be considered with equally powerful tugs on a number of positions with applicable impinged jet losses7 securing a controlled berthing approach. Tier II – dynamic analysis – includes ship dynamics in the horizontal plane. Whereas tier I provides an outline requirement presuming a ‘dead’ assisted vessel, tier II includes an assisted vessel’s inherent manoeuvrability and controllability from propellers, rudders and bow thrusters. Tier II analysis includes a range of scenarios with wind fields, variable currents and banking effects to create an understanding of required tug performance space during the full harbour approach.

A tugboat’s principal purpose is to provide pilots with additional controllability of the assisted vessel. The extent of the required controllability depends on predetermined operating windows, infrastructure layouts, typical assisted vessels and risk policy for harbour areas – because how safe is safe enough? What does that really mean – and safe enough for whom? What kind of procedures need to be considered in case of non-normal operations?

Fast-time simulation tools can run many scenarios within the tier II analysis scope. Fast-time simulation programs – MARIN Shipma (version 7.0) and others (Figure 1) – enable identification of benchmark scenarios within a harbour or terminal operating window. Such programs are often considered during port developments, especially in relation to developing layouts and bathymetry. Applying these programs to develop effective performance space and functional tug requirement is an underappreciated application of fasttime simulation, and enables effective use of Tier III – real-time simulation time and resources.

Multiple views from various stakeholders can be expressed within the safety frame of operations: ship owners, regulatory bodies, terminal operators, those involved in tug (crew) safety. Generating consensus between stakeholders involves finding the sweet spot between available technology, operating psychology and economics. Finding this sweet spot is what Tugconomy is all about. Tugconomy is a concept about value for money for stakeholders in, and related to, towage services. It is about finding towage solutions without a bias, based on previous experiences, both good and bad. Tugconomy believes in always looking for better solutions and making efficient and effective use of resources. It is about taking into account the operational profile of a tug: intended application and operations, asset lifecycles, contract term expirations and so on. Tugconomy is about transparency and reproducibility and therefore stands at the very basis of any towage system’s functional requirements.

CASE STUDY: GREENFIELD FLNG

Bollard pull is any tug’s primary performance indicator and a subset of tugs’ respective performance space. Determining total bollard pull required to control an LNG carrier or other assisted vessel is often subject to discussion, with as many opinions as there are experts. Tugconomy discards opinions, instead enabling a multitiered, transparent approach, enabling and including expert views at every tier.

Figure 1: MARIN SHIPMA flow diagram

RISK ANALYSIS AND HAZARD IDENTIFICATION

Acceptable risk is a key criterion in any professional hazard identification and risk analysis. A reasonable sub-question would be: Acceptable to whom? Most risk analysis includes (maximum) likelihood and consequence matrices. Within this paper we will focus on operational risks in relation to a greenfield LNG terminal project, yet the principle can be applied to a range of marine operations (Table 1, opposite).

Tier I – static analysis – is a static desktop spreadsheet calculation on the basis of the OCIMF (Oil Companies International Marine Forum) and SIGGTO (Society of International Gas Tanker and Terminal Operators) methodology2 +20 per cent3. Alternatively, other methods can be applied to determine wind4, current5 and wave6 forces finding guidance in dynamic positioning methodology and literature. At this stage, the main focus is a static situation where the assisted vessel is controlled during a berthing manoeuvre.

A failure is here defined as a condition of nonserviceability of the operation. Within this scope, environmental conditions and/or loads can exceed the towage service capability (Figure 2, opposite), prompting a suspension of marine operations. Three types of failures can be identified in this manner, where

With a listed serviceability interval of the marine operation and MET dataset, this enables anyone to establish a basic tug requirement. At the very basis of a tug’s functional requirement is the static performance 2

KEY Very Low: Acceptable level of risk. Further analyses not needed. Low: Acceptable level of risk Medium: Represents a manageable level of risk. Controls required, implemented and verified. High: Extensive risk controls must be immediately implemented. Very High: Stop activities unless risk controls have been implemented and the risk is reduced to a lower level.

Table 1: Example likelihood and consequence matrix respective consequence ratings are self-evident. The extent to which a temporary suspension of service is acceptable must always be subject to a terminal’s operator risk policy.

operators in their field, and why there is an increasing focus on operator QHSE (quality, health, safety, environment) qualifications, and risk awareness and associated skill-levels among crews. Some hazards and risks cannot be fully excluded because they are, by their very nature, beyond our control, but we can procure fit-for-purpose tugs designed to provide crews with the tools to mitigate the consequences of this type of failure.

Reversible, excess windage T

ALARP is a term often used in the towage industry, underlying the comparative nature of technologies and procedures deployed in the field. Within this framework, Tugconomy appeals to the reasonableness and practicability of towage solutions. But perhaps the principal underlying questions are: acceptable risk to whom, and what are my options?

Non-reversible, allision with terminal T

Reversible, after repairs: towline failure

Technology

T

Psychology

Figure 2: Towage service capability

ACCEPTABLE RISK POLICY

Economics

Acceptable risk is a comparative measure. FMEAC (failure mode, effects and criticality) analysis should ultimately benefit the decision-making process in the development phase of marine greenfield operations. How does one technology or tug concept compare to the other and what details in tug design can benefit operational safety? Creating value, by identifying key areas where additional capital investment and operating expenses provide value for money, appeals to decision-makers.

Figure 3: Technology, economics and psychology Decision-making involves combining the above disciplines (Figure 3) into acceptable towage solutions – ie, those providing the most effective vectors and leverage to assisted vessels in a practicable manner. Maximising berth availability, minimising operational delays, securing safe work conditions and providing

Some failure modes can be mitigated by procedural means. That is why you want to deal with expert 3

a cost-effective towage service capability, including marketable assets (tugs) should be an integral part of infrastructure developments considering a towage service.

of Tugconomy, all such functional requirements are addressed and weighted providing competitive – and effective – support services.

TUGCONOMY

Identifying performance space requirements and benchmark scenarios in tier II fast-time simulations8 enables effective use of tier III real-time resources. Real-time simulations can take 2hrs/run involving a team of marine pilots and tug masters, often in a consultancy capacity. Considering one week’s testing amounts to 16-20 runs to test a range of scenarios, resources are limited indeed. Running tier I desktop and tier II fast-time simulation prior to such simulations ensures key benchmark performance scenarios are identified beforehand, and non-normal operations can be considered.

TIER III – A TOUCH OF ELEGANCE

Within the framework of Tugconomy, the question is whether better solutions are available and, if so, to what extent are they practicable? The Tugconomy concept applies both to individual technologies and sub-system designs, and includes tug concepts and designs, as well as procedures designed to successfully deploy tugs and react to unexpected events. But Tugconomy is also about economics, with cost breakdowns where crew expenses are a substantial part of an operator’s cost base. Such a cost base, and high-powered engines, inevitably create a drive for fewer, but more powerful, tugs – consequently altering the towage operation/tug deployment and the towage service failure modes.

Real-time simulations are where the human element comes into the equation. Anticipating manoeuvres, there is a lot to say in favour of including human skilllevels in that equation. Real-time simulations also enable you to include non-normal operations as an additional layer of complexity, and to compare suitability of tug concepts for your operation.

Creating public support for terminal and/or port infrastructure developments requires a structured and transparent approach to how we go about managing navigational risks in marine operations. The psychology of a marine operation involves all stakeholders, ranging from the not-in-my-back-yard neighbours to crews – and associated unions – operating in front of a ULCC at 8 knots, and US EPA-required additional emissions controls for engines >2,000kW. In towage terms, that means any tug of more than 60 tonnes BP. Exploring and comparing multiple tug concepts appears to be a sensible and transparent approach to covering these liabilities.

Tugconomy is about zeroing in on your towage solution, increasingly defining and refining the boundaries of a tug’s performance space for ship and/ or tug-handling concepts. Marine pilots require vectors, but act with caution in case of ‘vector’ tugs. Vector response and jet-impinged thrust phenomena are tricky to grasp at best. Jet-impinged thrust losses, from propeller wash impinging on the assisted vessels, can range from 23-62 per cent9.

In particular, greenfield LNG developments favour this unbiased approach to determining towage requirements and define both the functional requirements and technology meeting those requirements. Tugs often provide myriad functional requirements within the wider QHSE scope, with a differentiation between the primary navigation risks and, for example, fire-fighting, stand-by or oil pollution prevention. Within the scope

Auditing the simulation centres beforehand to ensure that such physics phenomena are included appears to be a sensible approach. Auditing subcontractors and suppliers is becoming an increasingly common phenomenon among global operators. Including simulation requirements to provide and include new tug concepts in their portfolio is a straightforward policy which any simulation software provider can endorse.

Assisted vessel, Basic MET conditions, Basic Bathymetry, Serviceability level Tier 1 – SIGGTO/OCIMF

Tier 2 – Fast-time simulations Scenario-driven Tier 3 – Real-time simulations, human factors Non-normal operations Towage solution Figure 4: Towage in port development 4

NON-NORMAL OPERATIONS

secure greenfield developments and quantify expert views while excluding human operator bias.

Limited resources, or more specifically available runs, restrict the number of non-normal operations and associated procedural actions to be explored. Nonnormal operations can be distinguished between general failures, such as towline failures, and total blackouts. Both can be mitigated by either split/double drums, or turning around, using another winch (Rotortug) or using 24V back-up systems. There really is no differential with regard to tug concepts in these circumstances, or it is a differential that can be successfully simulated.

FOOTNOTES

All tugs have a fully-developed theoretical performance ‘space’, indicating their respective towing capability, Performance Matters – A Case Study, Marinus Jansen, Tugnology ’15, London 2 Mooring Equipment Guidelines, 3rd edition, OCIMF, 2013 3 Tug Use in Port – a practical guide, Hensen, Nautical Institute, 1997 4 DNV-RP-C205: Environmental conditions and environmental loads, October 2010 5 Modified strip-theory 6 Sea Loads on Ships and Offshore Structures, Faltinsen, OM, Cambridge University Press, 1990 7,9 SafeTug Offshore berthing operability methodology, MARIN, January 2008 8 eg, MARIN SHIPMA programme 10 Force Technology: Tackling the Rotortug challenge, Jesper Nielsen, International Harbour Masters Congress 2012 1

The other types of failure consider the tug’s or assisted vessel’s propulsion and steering system. Considering two tug concepts to create a comparative analysis further reduces the available runs to about four or five per tug concept. The following list of scenarios should be considered as a minimum: •  Loss of steering assisted vessel. •  Loss of propulsion assisted vessel. •  Temporary (5 mins) loss of propulsion unit on centrelead fore tug. •  Temporary (5 mins) loss of propulsion unit on centrelead aft tug. •  Pursuing ALARP risk levels should by all means include an analysis of different tug concepts. Rotortug BV, the technical marketing company dedicated to the development of the Rotortug concept, has supplied tug design – and trial data – to a range of simulator software suppliers as a policy for a number of years10. Within this scope, the key issue is whether you can afford not to review alternative tug concepts, and how these might mitigate hazards in a marine operation. Note: Tugconomy is not just about incorporating the triple Z-drive Rotortug in the aforementioned analysis. Other concepts, such as SDMs, are out there and available and these successfully meet their intended design criteria. However, some of these concepts may lack versatility with regard to their intended application and long-term operation after contract expiration.

CONCLUSION

Developing towage service functional requirements includes many different stakeholders with as many interests. Acknowledging that port development includes social engineering (and design, by its very nature, is a social process) and requires a transparent and unbiased approach to stakeholders. Such bias can be mitigated only by having multiple technologies and tug concepts acting in competition, within the scope of a marine operations development. Within this framework, Tugconomy involves a transparent design cycle, establishing a firm performance space requirement and including nonnormal operations during the front-end development phase – thereby providing greenfield marine operations with a cost-effective and ALARP towage solution. Expert opinions alone are not sufficient to align stakeholder interests and mitigate an operator’s liability. Tugconomy provides a framework model to establish 5

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