Operational guide · Certification & surveys

Managing Surveys under Dual/Multiple Classification

Double class and dual class describe different arrangements. Survey responsibilities must follow the participating societies’ documents.

dual classIACSclassificationsurveytransfer of class

Operational Explanation

In double class, each of the two societies acts as if it were the sole class. In dual class, a written bilateral agreement governs work sharing. IACS PR 1B addresses these arrangements; PR 1A addresses transfer of class. Withdrawal of one class is not automatically a transfer.

Regulatory Reference

IACS PR 1B; Society Rules and applicable agreement. As of 15 September 2026: PR 1B Rev.8 current; Rev.9 from 1 January 2027.

On withdrawal from double class, the remaining Society must obtain the owner’s written intention and authorization to exchange status. It requests status within two working days of receipt at its head office or designated centre. Overdue conditions do not disappear: failure to close them at the first port where surveys can be performed can result in suspension, subject to the age-related allocation of responsibilities and any accepted direct voyage to a repair port. Withdrawal from dual class follows the agreement between the Societies. PRS 97/P, January 2026, §§2.6–2.7.

Scope of Application

PR 1B covers double/dual class within its scope. For more than two societies, verify specific agreements and Rules; flag statutory delegation must be checked separately.

Procedure / How to Complete It

Identify double or dual class and obtain the relevant agreement.
Compare both societies’ status, deadlines and outstanding conditions.
Agree attendance, reports, acceptance of work and condition closure in writing.
After the survey, check both status records and affected statutory documents are updated.

Practical Example

Do not assume one society’s report automatically closes the other’s conditions: check the agreement and obtain documented confirmation of credit and status.

What Typically Goes Wrong

Confusing double and dual class; using only one status; assuming all work is automatically accepted.

Common Mistakes Mistake Library

Mistake	How to avoid it
Confusing double and dual class; using only one status; assuming all work is automatically accepted.	Check the individual ship’s requirements and documents before closing the work.

What the PSCO Checks

Double classification does not replace statutory certificates or checks of the ship’s condition. Identify each certificate’s authorized issuer and relevant restrictions; a class agreement does not itself confer flag delegation.

Operational Tips

Use a matrix of tasks, responsible society and closure evidence.
Record confirmations from both societies.

Preparation checklist

Arrangement and agreement identified
Two status records reconciled
Responsibilities and credits confirmed

FAQ

Are double and dual class synonyms?

No. In dual class, work sharing is governed by a written bilateral agreement.

Which PR addresses these arrangements?

IACS PR 1B; transfer of class is addressed by PR 1A.

Which PR 1B revision is current?

As of 15 September 2026, Rev.8; Rev.9 takes effect on 1 January 2027.

Managing Surveys under Dual/Multiple Classification

Operational Explanation

Regulatory Reference

Scope of Application

Procedure / How to Complete It

Practical Example

What Typically Goes Wrong

Common Mistakes Mistake Library

What the PSCO Checks

Operational Tips

Preparation checklist

FAQ

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