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SMM SHIP PERFORMANCE (SMM-SP). CHALLENGES FOR SHIP OWNERS/MANAGERS/OPERATORS. Technical Specification: insufficient description of the promised performance Model Tests: narrow scope and insufficient results of the predicted performance
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CHALLENGES FOR SHIP OWNERS/MANAGERS/OPERATORS • Technical Specification: insufficient description of the promised performance • Model Tests: narrow scope and insufficient results of the predicted performance • Sea Trials: lack of verification of the performance predicted from model tests (Speed, Power AND RPM) + no provision of the ship's final calibrated performance status at different drafts, speeds and average hull roughness + no final calibrated ship performance reference values • Technology: instrumentation with less than promised accuracy and repeatability • Charter-Party Agreement: made for disputing a single value, instead of considering the ship's reference performance envelope in a holistic manner
PERFORMANCE RELATED ISSUES • Sister Ship with significantly different behavior in adverse weather conditions and maneuvering • Weather Routing Providers with performance standards without sound technical criteria • Inappropriate Model tests due to alterations in assumptions effected • Lack of sound commercial reporting • Increased Performance claims due to the collapsed Freight Rates market • No time for crosschecking the daily reports provided by shipboard personnel • Huge Investments on performance monitoring tools with unsatisfactory results
METHODOLOGY Based on hard evidence (shipbuilders' documentation, ie. Sea trials, model tests, etc.) No Current Effects compared to Speed over ground and no wake fraction estimation in contrast to Real Slip Elimination of all measurements complexities and uncertainties coming from the fluctuating environmental and operational conditions (Waves, Trim, Draft, Wind etc.) APPARENT SLIP METHOD Your ship performance standards based on sound technical criteria ADVANTAGES The methodology based on Telfer (1924): • “the propeller does not sense wind, waves, fouling or any other resistance. It does sense a reduction in the rate of inflow”. • Rate of inflow variation incorporated in the term Apparent Slip related to reference brake power for a recommended range of operating speeds through water.
BASIC PARAMETERS OF SMM-SP Minimum data Collection for Maximum End Result: • Speed = Vs, Speed through Water • Apparent Slip, Function {Vs, RPM, Pitch} = Based on above as being ascertained and calibrated from model tests and sea trials, we derive the following for the several modules of SMM-SP: • The Power-Speed-Slip functions (ship-specific) • Power = PB, Brake Power Function { Vs , Apparent Slip } • Daily Fuel Oil Consumption = Function { Power , SFOC } • Light Running Margin = Function { Power , RPM , Weather } • Overall Voyage Assessment = Function { FOC, Time Calculation, Charter Party Claims}
THE SIGNIFICANCE OF APPARENT SLIP FIGURE? For any given set of conditions of Brake Power, RPM (N) and Speed Through Water (STW, Vs), there is a value of propeller diameter and pitch ratio for optimum efficiency. It follows that there is a corresponding optimum value of apparent slip.
TYPICAL SHIP-SPECIFIC POWER REFERENCE VALUES Range for application for a typical LNG Vessel:
SMM-SP SOFTWARE FOR ONBOARD AND OFFICE USE INVOLVES: Initial Calibration: Based on sea trials data or client’s provided propulsion performance measurement reports (Propulsion Powering Reference) Voyage Performance (Overall Voyage Assessment) Propulsion Performance (Overall Engine - Fuel System Evaluation) Light Running Margin Monitoring (Fouling Monitoring, Hull Roughness) Hull Surface Savings (Relative Gain for Hull Cleaning or new coating application) • Feasibility (Free of Charge): A qualitative review to confirm sufficiency of information and the feasible envelope of ship speeds and apparent slips • Set-Up: Preparation of vessel-specific mathematical models • Support, Calibration, Consultancy and Updates during service period
INFO REQUIRED FOR SMM-SP The following information will need to be collected and forwarded in electronic format or hard copies: • Ship Type and Particulars • Model Tests Report • Sea Trials Report • Propeller Plan/Drawing • Engine Particulars • Shop Tests Report and, if available, the Engine Manufacturer’s Nominal SFOC Table at ISO Conditions
PROVISIONS FOR GOOD MEASUREMENTS • It is recommended to exclude measurements when any of the following conditions apply: • Strong currents (i.e. >1.5 knots), Ship drifting, Beam winds and seas. (i.e. Vs-trans > 0.5 knots) • Large fluctuations of speed, Large ship motions • Acceleration and deceleration of the ship, Periods of transit • Propeller emergence and ventilation • SS>3, BF>4 • Outside the range of Drafts found in model tests report. • Outside the range of Speeds tested in model tests report.
25 % of observations found to be within the range of SS0-SS4 in North Atlantic
COMPETITIVE ADVANTAGES OF SMM- SP OVER COMPETITION • Easy to implement and minimum administration and equipment cost • Support and consultancy about several issues concerning performance aspects of monitored vessels and any relevant issues arising throughout the service period • Accuracy (SMM-SP) uses only the minimum number of parameters compared to other methods such as Resistance Decomposition and Artificial Neural Network) • Elimination of numerous complexities and uncertainties (wave, wind etc.) • SMM-SP focusing on warranty conditions constituting a fair evaluation of ship’s performance with respective sets of quality measurements • Value for Money
DRAWBACKS OF OTHER METHODOLOGIES • Resistance Decomposition • High uncertainty due to the plethora of involved parameters • The lack of reliable and accurate methodology to evaluate the different components of Resistance such as Wave Resistance, (statistics, etc) • Very Expensive Equipment for Monitoring • Neural Networks • High Uncertainty based on the Self-Learning Method and the number of variables involved • Very Expensive Equipment for Monitoring • Weather Routing Software • Unsatisfactory results in many cases due to non scientifically sound formulas used
SUMMARY OF BENEFITS • Overall Voyage Assessment • Overall Engine-Fuel System Evaluation • Monitoring Roughness & Fouling • Provision of sound commercial reporting • Monitoring of Shipboard Personnel • Compliance with Environmental & Energy Regulations and Industry Standards (EEOI, SEEMP, ISO 50001-EMS, TMSA, MRV) • Evaluation of the milestones (i.e. Overhauling of M/E, Underwater Cleaning etc.) • Assessment of Hull Cleanings and New Coating Application