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SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD THAT HAS PASSED THE END DATE: 

Demonstrate an understanding of ship stability 
SAQA US ID UNIT STANDARD TITLE
261077  Demonstrate an understanding of ship stability 
ORIGINATOR
SGB Maritime Defence 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 08 - Law, Military Science and Security Sovereignty of the State 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 5  Level TBA: Pre-2009 was L5  5 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Passed the End Date -
Status was "Reregistered" 		 2018-07-01  2023-06-30  SAQA 06120/18 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2024-06-30   2027-06-30  

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.  

This unit standard does not replace any other unit standard and is not replaced by any other unit standard. 

PURPOSE OF THE UNIT STANDARD 
This unit standard is intended for learners within the Maritime Sector who work/wish to work as an officer on the bridge of a ship. This Unit Standard meets the needs of the sub-field and of the society by providing competent maritime officers who by being able to maintain the stability of a ship, contributes to a safer environment on the ship and at sea. The learner successfully completing this Unit Standard will gain essential knowledge and practical skills required to determine whether a ship has sufficient stability to put to sea and can maintain positive stability in a seaway.

The competencies achieved by the learner in this Unit Standard will, in the case of the Merchant Navy and the Fishing Industry, contribute to the economic upliftment of the country, and in the case of the South African Navy, contribute the preservation of human life and the defence of South African warships, territorial waters and/or area of responsibility, thus providing a safer and secure society for South African citizens.

Learners credited with this unit standard will be able to:
  • Demonstrate an understanding of ship stability assessment.
  • Demonstrate an understanding of the effects of the movement of the centre of gravity on the ship during loading operations or while on passage.
  • Demonstrate understanding of the effect of slack and fresh water tanks on ship stability.
  • Demonstrate understanding of the fundamentals of watertight integrity. 
    		•

    LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
    It is assumed that the learner has the following knowledge and skills:
  • Communication at NQF Level 4.
  • Mathematical Literacy at NQF Level 4. 
    		•

    UNIT STANDARD RANGE 
    N/A 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Demonstrate an understanding of ship stability assessment. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    An explanation is given of the relationship between the mass of a ship and the volume of water it displaces with reference to Archimedes' principle. 
    ASSESSMENT CRITERION RANGE 
    The explanation includes light displacement, load displacement, deadweight, tonnes per centimetre immersion (TPC), density, displacement/draught curve, deadweight curve/scale, Tonnes Per Centimetre scale and Tonnes Per Centimetre formulae.
     

    ASSESSMENT CRITERION 2 
    A description is given of the statical stability of a ship afloat with reference to the relationship between stability, righting lever and righting moment for small and large angles of heel. 
    ASSESSMENT CRITERION RANGE 
    The explanation includes centre of gravity, centre of buoyancy, metacentre, metacentric height (GM), righting lever (GZ), righting moment, "stiff" and "tender" as well as their associated dangers, stable and unstable, neutral equilibrium and capsizing moment.
     

    ASSESSMENT CRITERION 3 
    A description is given of the dynamics of a ship at the angle of loll in terms of the dangers of a ship rolling about this angle of loll. 

    ASSESSMENT CRITERION 4 
    A description is given of how stability curves are used to determine accurately the metacentric height and the range of stability of a ship. 
    ASSESSMENT CRITERION RANGE 
  • Stability curves include KN curves (cross curves of statical stability), righting lever (GZ) curve.
  • Range of stability includes stable and initially unstable ships, maximum righting lever and the angle at which it occurs, angle of vanishing stability, range of stability and effect of lowering position of gravity.
     
    		•

    ASSESSMENT CRITERION 5 
    A description is given of the effect of the down flooding angle on the curve of stability for a particular ship in terms of its implications for ship stability. 

    SPECIFIC OUTCOME 2 
    Demonstrate an understanding of the effects of the movement of the centre of gravity on the ship during loading operations or while on passage. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    An explanation is given of the relationship between centre of gravity, centre of buoyancy and metacentric height with reference to the stability of the ship. 

    ASSESSMENT CRITERION 2 
    The movement of the centre of gravity of a ship during loading operations is demonstrated with the aid of diagrams and calculations. 

    ASSESSMENT CRITERION 3 
    The change in Ship's Center of Gravity Above Keel (KG) is calculated resulting from consumption of fuel, stores, absorption of water by deck cargo and accumulation of ice on upper decks and superstructure. 

    SPECIFIC OUTCOME 3 
    Demonstrate understanding of the effect of slack and fresh water tanks on ship stability. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    An explanation is given of the movement of the centre of gravity in a partly filled tank during rolling with reference to the free surface effect. 

    ASSESSMENT CRITERION 2 
    An explanation is given of the implications for Ship's Center of Gravity Above Keel (KG)of a partially filled space with reference to the effects of breadth and mass of liquid contained. 

    ASSESSMENT CRITERION 3 
    A description is given of specific ship construction measures with reference to their impact on free surface effects. 

    ASSESSMENT CRITERION 4 
    A description is given of the procedures for ballasting tanks with reference to their impact on a ship at an angle of loll or with a small positive Metacentric Height (GM). 

    ASSESSMENT CRITERION 5 
    An explanation is given of the relationship between draft and density of seawater or dock water with reference to implications for ship stability. 

    SPECIFIC OUTCOME 4 
    Demonstrate understanding of the fundamentals of watertight integrity. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    A description is given of watertight integrity in terms of the consequences for stability, trim and stress. 

    ASSESSMENT CRITERION 2 
    A description is given of the consequences for the ship of partial loss of intact buoyancy, together with actions to be taken to maintain ship stability. 

    ASSESSMENT CRITERION 3 
    A description is given of actions that must be taken to to ensure and maintain the watertight integrity of the ship. 


    UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
  • An individual wishing to be assessed (including through RPL) against this Unit Standard may apply to an assessment agency, assessor or provider institution accredited by the relevant ETQA, or an ETQA that has a Memorandum of Understanding with the relevant ETQA.
  • Anyone assessing a learner against this Unit Standard must be registered as an assessor with the relevant ETQA or with an ETQA that has a Memorandum of Understanding with the relevant ETQA.
  • Any institution offering learning that will enable achievement of this Unit Standard or assessing this Unit Standard must be accredited as a provider with the relevant ETQA or with an ETQA that has a Memorandum of Understanding with the relevant ETQA.
  • Moderation of assessment will be conducted by the relevant ETQA at its discretion. 
    		•

    UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
    Embedded knowledge includes:
  • Safety of Life At Sea Convention, as amended.
  • Seafarer's Training, Certification and Watchkeeping Convention, as amended. 
    		•

    UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    Identifying and solving problems in which responses display that responsible decisions using critical and creative thinking have been made when:
  • Demonstrating an understanding of ship stability assessment.
  • Demonstrating an understanding of the effects of the movement of the centre of gravity on the ship during loading operations or while on passage.
  • Demonstrating understanding of the effect of slack and fresh water tanks on ship stability.
  • Demonstrating understanding of the fundamentals of watertight integrity. 
    		•

    UNIT STANDARD CCFO COLLECTING 
    Collecting, analysing, organising and critically evaluating information to better understand and explain:
  • Ships stability assessment.
  • The effects of the movement of the centre of gravity on the ship during loading operations or while on passage.
  • The effect of slack and fresh water tanks on ship stability.
  • The fundamentals of watertight integrity. 
    		•

    UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    REREGISTRATION HISTORY 
    As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015. 

    UNIT STANDARD NOTES 
    The following scope and context applies to the whole unit standard:
  • International Maritime Organisation stability requirements for a cargo ship (Seafarer's Training, Certification and Watchkeeping Code Table A-II/1: Seaworthiness).
  • South African Maritime Safety Authority: Merchant Shipping (Training and Certification) Amendment Regulations, 2006. 
    		•

    QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Elective  64929   National Certificate: Vessel Safety Practices  Level 5  Level TBA: Pre-2009 was L5  Passed the End Date -
    Status was "Reregistered"     		 2023-06-30  SAS SETA 


    PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD: 
    This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.
     
    NONE 


    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.