DNV GL Rules - January 2021 edition

The 2021 January edition of the DNV GL rules is now available.

The 2021 January edition of the DNV GL rules is now available on our Rules and Standards page.

1. General information

New and amended rules were formally approved on January 14th 2021 by Group CEO Remi Eriksen and are included in the January 2021 publication of the rules.  

The main changes to the rules cover:

  1. Rules for Ships:
    a) Revised class notation
    b) General updates and corrections
  2. Yachts - new class notations

The entry into force date for these rules is 1st of July 2021.   The rules may, however, be applied to projects contracted before this date upon agreement between parties.

For more information on the changes, please contact your local DNV GL office. 

Below is given a general overview of the main changes in the rules for classification of ships and the rules for classification of yachts.

2. Rules for Ships

Main class

Topic    Rule reference
Type of change

Materials and welding
Fabrication and testing

Pt.2 Ch.4 Sec.7Topic revison
NDT methods

Class notations

Class notationRule reference
Type of change


Pt.5 Ch.10 Sec.10Topic revision
Propeller loads
Tugs and escort vesselsPt.5 Ch.10 Sec.11Topic revision 
Towing winch emergency
release systems
Double acting vesselsPt.6 Ch.6 Sec.7Topic revision
Propeller loads

Updates commented

a) Materials and welding

  • IACS documents related to NDT have been updated, extended and put to a higher level. The new IACS requirements UR W33 and W34 complete a consistent overall picture of NDT requirements in the maritime industry.
  • Rules update in relation to IACS UR W33
    • added table for delay time requirements based on the strength levels of the materials
    • revised minimum parent material thickness requirement
    • aligned standards, abbreviations, quality levels and acceptance criteria.
  • Rules update in relation to IACS UR W34
    • Included definition of ANDT (advanced NDT) methods, standards, abbreviations, acceptance criteria
    • added qualification procedure for ANDT methods.

b) Icebreaker

  • The propeller loads for open propellers and ice pressure for structural loads have been reduced to meet actual operating conditions.

c) Tugs and escort vessels

  • Implemented IACS resolution UR M79 (rev1 Feb 2020) regarding towing winch emergency release systems.
  • Aligned with definitions for ‘black out condition’ and ‘safe location’.
  • New documentation requirement for test procedure for quay and sea trials for emergency release systems for all types of tugs.

d) Double acting vessels

  • Following changes to rules for Icebreakers, the backward blade force factor for DAV with icebreaker notation has been decreased from 1.2 to 1.1 accordingly.

3. Rules for Yachts

Class notation

Class notationRule reference
Type of change


Pt.6  Ch.2 Sec.1New notation
  • Offering a new class notation (MC) differentiating on the requirements for certification of  machinery systems and components based on yacht type/size.

4. Information on coming rule editions

DNV GL publishes main rule editions annually.  The next main rule edition will be published in July 2021.

Additional amendments may be carried out, and all amendments will be specifically marked in the rules table of contents found here.  

Oslo, Norway, 2021-01-21

Henning B. Karlsen

Service Responsible – Ship Class

29 April 2022

IMO maritime safety committee (MSC 105)

The 105th session of the IMO’s Maritime Safety Committee (MSC) was held remotely from 20 to 29 April. A wide range of topics was on the agenda, including the safety of ships carrying industrial personnel, the safety of ships relating to the use of fuel oil, and the consideration of a regulatory framework for maritime autonomous surface ships. Requirements reflecting modern systems for maritime distress and safety communication were adopted and interim guidelines for the safety of ships using fuel cell power installations were approved. The development of interim guidelines for ships using ammonia as fuel were initiated.

  • Maritime
11 April 2022

IMO sub-committee on pollution prevention and response (PPR9)

The 9th session of the IMO’s Sub-Committee on Pollution Prevention and Response (PPR 9) was held remotely from 4 to 8 April 2022. A wide range of topics was on the agenda, including biofouling, ballast water management, black carbon, sewage treatment and marine plastic litter. PPR agreed on draft guidelines on risk and impact assessments of the discharge water from exhaust gas cleaning systems when considering local or regional regulations.

  • Maritime
24 March 2022

SEEMP Part III and the upcoming SEEMP Generator from DNV

Since 2019 ships of 5,000 GT and above have been reporting their fuel oil consumption data mandated by the IMO DCS. From 2023, cargo, cruise and RoPax ships must calculate CII with a required rating of C or better. This means some ships will have to improve their carbon intensity. A verified Ship Operational Carbon Intensity Plan, or SEEMP Part III, is to be kept on board from 1 January 2023 to document how you plan to achieve your CII targets. This statutory news provides an update on the SEEMP Part III and recommends next steps.

  • Maritime
07 March 2022

IMO Sub-Committee on Ship Systems and Equipment (SSE 8)

The 8th session of the IMO’s Sub-Committee on Ship Systems and Equipment (SSE 8) was held remotely from 28 February to 4 March. SSE 8 finalized draft new ventilation requirements for lifeboats and liferafts, and draft new guidelines for the design, construction, installation, testing, maintenance and operation of lifting appliances and anchor handling winches. Good progress was made on the new mandatory requirements to minimize the incidence and consequences of fires on ro-ro passenger ships, and on the work to improve the safety of commercial diving operations.

  • Maritime
14 February 2022

IMO Sub-Committee on Human Element, Training and Watchkeeping (HTW 8)

The 8th session of the IMO’s Sub-Committee on Human Element, Training and Watchkeeping (HTW 8) was held remotely from 7 to 11 February. Highlighting the human element as a key factor both for safety and environmental protection, HTW 8 agreed on a revised checklist for considering the human element in the review, development and implementation of new and existing IMO requirements. HTW 8 also agreed on amendments to the STCW Convention and Code to accommodate the use of seafarers’ electronic certificates and documents.

  • Maritime
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