The Marine Environment Protection Committee (MEPC) of IMO has agreed on a schedule for global phase-out of single-hull tankers. Draft amendments to the critical Regulation 13G of Annex I to the Marine Pollution Convention (MARPOL 73/78) were finalised and adopted, entering into force 1 September 2002.

A timetable for mandatory withdrawal from commercial service was adopted, taking into account the anniversary dateof the year of build (see table). A limited life extension may be granted subject to compliance with the Condition Assessment Scheme (CAS).

CAS purpose
The main purpose of CAS is to introduce a veracity check of the hull condition, as opposed to adding yet another layer to existing survey requirements or specifying structural standards in excess of IMO provisions.

CAS implies strict adherence to existing IMO structural standards by strengthening the effective application of the Enhanced Survey Programme (ESP), as contained in IMO Assembly Resolution A. 744(18) as amended. As a consequence, CAS surveys will normally be carried out in concurrence with the renewal of intermediate surveys required under ESP.

CAS seeks to enhance owner and class co-operation as well as strengthen both class supervision and Flag Stateimplementation, in order to obtain the intended results. The critical focus is to ensure that surveys are planned according to strict procedures, with required detail of documentation and close involvement of both owner and classification society in the survey plan approval. A standard questionnaire has been developed to facilitate the process, followed by development of a model survey plan.

CAS includes comprehensive reporting requirements for the classification society. The reports will be verified by the Administration, or an appointed expert, before a Statement of Compliance, valid for a maximum of 39 months, is issued.

Two qualified exclusive surveyors will attend the ship for a CAS survey. During thickness measurements an exclusive surveyor will be present to supervise the process.

A demand for a second opinion to the work executed by the classification society has not been retained. Instead the Administration will establish procedures for monitoring and verification of CAS survey and reporting. These will be performed by qualified persons directly controlled by the Administration, and not connected to the classification society performing the CAS survey.