Follow us in Social Media alternative text alternative text SMM Twitter page alternative text alternative text

Frequently Asked Questions for SMM Products

SMM - Ship Performance Frequently Asked Questions
What is the technical background of the SMM-SP software?


SMM-SP is a toolbox for the assessment of ship propulsion performance.  Unlike other software solutions found in the market, SMM-SP does not need to decompose the various ship resistance elements, nor introduce higher uncertainties for normalizing the measurements from actual operating conditions.   

The SMM-SP toolbox contains a variety of solvers, specific to the ship:       

·         For the Voyage Performance module,  the solver is based on the monitoring and reporting of basic parameters during the voyage, their comparison against reference values under actual conditions and charter party terms and warranty conditions.  

Overall Voyage Assessment = Function { Fuel Consumption Calculation, Time Calculation, Charter Party Claims }    

Daily Fuel Oil Consumption = Function { Power , Specific Fuel Oil Consumption }       

·         For the Light Running Margin module, the solver is based on the principle that under same weather conditions, the margin reduces due to the increase of hull roughness and fouling.  The software captures the reduced margin over time. 

Margin Function { Power , RPM , Weather}      

·         For the Hull Surface Savings module, the solver is based on ship-specific algorithms, which estimate the loss of speed and increase of power by interpreting the findings of underwater inspection. The software allows the operator to derive the relative gain ($/year) in deciding hull cleaning or new coating application.  

With the software in place, the user can then:  

  1. evaluate the voyage performance against Charter Party terms and provisions
  2. compare the measured values during service with the respective reference values for power and fuel consumption
  3. monitor the light running margin due to increased roughness and fouling over time
  4. monitor the condition of the underwater hull surface and derivation of the savings from hull cleaning or new coating application


Is the SMM-SP service applicable for all ships?

The SMM-SP service is applicable for modern merchant vessels built with fixed pitch propeller, including but not limited to: General Cargo Vessels, Bulk Carriers, Ore Carriers, Chemical/Product/Oil Tankers, Gas Carriers, Container ships, etc.

Why is the feasibility stage necessary?

The feasibility stage is necessary in order to verify that the information provided is sufficient as well as suitable for the preparation of the ship-specific software service. If the information proves sufficient and suitable for purpose, then the ship-specific mathematical model will have a defined envelope (max-min) of ship speeds and apparent slips, within which the solvers will perform.


What information do I need to forward to SMM for the feasibility stage?

The following information will need to be collected and forwarded in electronic format or hard copies: 

  • Ship Type and Particulars
  • Model Tests Report
  • Propeller Plan/Drawing
  • Engine Particulars
  • Shop Tests Report and, if available, the Engine Manufacturer’s Nominal SFOC Table at ISO Conditions 

The hard copies are returned back to customer.



What is the periodic calibration and how often is this carried out?


The SMM-SP toolbox contains ship-specific mathematical models.  Calibration is essential in order to ensure representation of a good engine system operation, according to the latest milestone set of quality performance measurements.  In general, performance measurements tend to be carried out at milestones: after launching, dry-docking or main engine overhauling.



Do I need all the measurements taken onboard?


Particular attention should be paid to the instrumentation and measurement procedures.  In order to achieve a meaningful comparison it is critical that the in-service measurements are taken on the basis of a well-defined methodology, using reliable, calibrated and accurate instrumentation.  

In order to reduce the scatter of the recorded data and ensure that the instrumentation provides the user reliable measurements, it is recommended to exclude measurements when any of the following conditions apply:  

1.             Large fluctuations of speed, Large ship motions. 

2.             Acceleration and deceleration of the ship, Periods of transit. 

3.             Propeller emergence and ventilation. 

4.             SS>3, BF>4.  

5.             Outside the range of Drafts found in model tests report.  

6.             Outside the range of Speeds tested in model tests report.



How do I review the ship's performance against the Charter Party?

The principle feature of a continuing warranty is that it should establish the benchmark against which Owners’ continuing obligations are to be measured.  The choice of words used will determine the warranty conditions that apply.  In an example, the warranty conditions are as follows:     

1.       In weather conditions not exceeding Beaufort Force 4     

2.       In sea conditions not exceeding Sea State 3   

3.       No adverse current    

4.       No adverse swell    

5.       No shallow waters 

6.       No restricted navigation  

Now, let us compare the conditions shown in the previous question “Do I need all the measurements taken onboard?”, with those in the example above.  It can be observed that the former conditions represent a more robust technical framework and one that should be aimed in charter party agreements.    

Therefore, SMM-SP takes into account the conditions which should apply for a fair evaluation of ship’s performance.    

Subsequently, when all conditions exist, the ship will be expected to demonstrate an ability to perform at the promised speed and consumption and will only be excused from doing so if one or more of the warranty conditions is/are absent.    

Periods of warranty conditions are sometimes loosely referred to as good weather days.  In fact, they should be more accurately described as good weather periods, as the periods of interest are not restricted to full days only.   

Therefore, the SMM-SP user should establish sufficient individual and cumulative periods of warranty conditions, with respective sets of quality measurements to permit a reliable and objective assessment of the ship’s performance.



“Committed to Improve your Ship & Operations”

All copyright reserved © 1986 -