Sub-Committee on Ship Design and Construction (SDC 12), 19-23 January 2026

The Sub-Committee on Ship Design and Construction held its 12th session at IMO Headquarters in London from 19 to 23 January and was chaired by Mr. Erik Tvedt (Denmark). 

Draft workplan agreed to develop a safety framework for selected GHG-reducing technologies 

The Sub-Committee finalised a workplan for the development of a safety regulatory framework to support the reduction of GHG emissions from ships using new technologies and alternative fuels, under the purview of the SDC Sub-Committee. This will be submitted to the Maritime Safety Committee (MSC 111) in May 2026 for approval. 

The timeline includes key milestones for developing or amending existing safety regulations related to: 

  • nuclear power; 

  • wind-propulsion and wind-assisted power; and  

  • lithium-ion batteries and swappable traction battery containers on ships.  

Some key milestones include: 

2026  

  • MSC 111: Endorsement of the work plan developed at SDC 12. 

2027  

  • SDC 13: Finalization of amendments to SOLAS regulation II-1/41 to allow for batteries to be used as the main source of electrical power and lighting systems. 
  • MSC 113: Approval of amendments to SOLAS regulation II-1/41 to allow for batteries to be used as the main source of electrical power  

2028 

  • SDC 14: Decision on whether to develop a unified interpretation, or guidelines, on installation requirements for a safety approval plate in battery containers, and, referring to SP389, storage and safety requirements for lithium-ion batteries in a swappable container. 
  • MSC 114: Adoption of amendments to SOLAS regulation II-1/41 to allow for batteries to be used as the main source of electrical power and lighting systems.

2029 

  • SDC 15:  Finalization of interim guidelines for the safety of ships using wind propulsion and wind assisted power.  
  • MSC 116: Approval of interim guidelines for the safety of ships using wind propulsion and wind-assisted power.

2030  

  • SDC 16: Finalization of the revised Code of Safety for Nuclear Ships (Nuclear Code) and amendments to SOLAS chapter VIII. 
  • MSC 117: Approval of amendments to SOLAS chapter VIII 
  • MSC 118: Adoption of the revised Nuclear Code and amendments to SOLAS chapter VIII. 


The Sub-Committee established the SDC Correspondence Group on GHG Safety to compile and analyse information related to nuclear and wind power, as well as develop draft amendments to SOLAS regulation II-1/41 to allow for batteries to be used as the main source of electrical power and lighting systems. The Correspondence Group will submit a written report to SDC 13. 

Actions to reduce underwater radiated noise from ships  

The Sub-Committee further progressed the work of the Organization under the Action Plan for the reduction of underwater radiated (URN) noise from commercial shipping (URN Action Plan), which was approved at MEPC 82 in 2024.   

Experience-building phase extended   

After analysing and discussing lessons learned to date from the three-year experience-building phase (EBP) initiated in 2024 from implementing the Revised guidelines for the reduction of underwater radiated noise from shipping to address adverse impacts on marine life (Revised URN Guidelines) (MEPC.1/Circ.906/Rev.1), the Sub-Committee agreed to invite the Marine Environment Protection Committee (MEPC 84) to extend the EBP for two more years, with a target completion year in 2028.  

Should this two-year extension of the EBP be agreed by MEPC 84, it would allow for an extended window to gain further experience in the application of the Revised URN Guidelines, providing more time to address the remaining gaps, needs and barriers related to the implementation of this IMO instrument.  

Draft technical guidance agreed for integrating energy-efficient and low irradiated noise solutions in ship design and retrofitting 

The Sub-Committee agreed to the draft technical guidance on co-optimizing energy efficiency and underwater radiated noise at the design and retrofit stage with a view to approval by MEPC 84.   

This circular provides supplementary technical guidance on integrating URN reduction with energy efficiency (EE), recognizing the synergies between the two frameworks and drawing on experience gained EPB and the outcomes of URN/EE workshops held in 2023 and 2025. 

Study on URN emissions  

The Sub-Committee agreed to the draft terms of reference for an IMO-commissioned study on URN emissions, and requested the IMO Secretariat to assess options to cover the cost of the study. The study will support the development of targets for reducing URN by generating in-water estimates and help in determining an URN baseline for ships, as well as for contemporary and future projections of URN emissions. 

Revision of the Interim guidelines for the use of fibre-reinforced plastics (FRP) within ship structures agreed  

The Sub-Committee agreed to the draft revised Guidelines for the use of fibre-reinforced plastics (FRP) within ship structures (MSC.1/Circ.1574) related to fire safety, for approval at the next session of the Maritime Safety Committee (MSC 111). 

Fibre-reinforced plastics is a family of composite materials that are light, strong and resistant to corrosion, attractive when compared to steel alloys, especially in construction of lighter ship structures. However, some types of FRP have combustion characteristics that make fire safety a key concern when applied onboard ships.  

The FRP guidelines provide guidance for ship designers and builders on the safe use of FRP in ship structures, especially in addressing fire safety risks associated to FRP materials. They help Administrations ensuring that relevant fire safety tests for FRP materials are carried out consistently by all Flag States, in line with SOLAS requirements, and in the wider context of Alternative Design and Arrangements.  

The draft revision incorporates experience regarding the assessment of the fire safety in the case of alternative designs, and addresses main fire safety aspects, including ignition potential of the FRP material, fire growth potential, firefighting strategies and equipment, and maintenance of the insulation to protect the FRP. 

Revision of the explanatory notes for passenger ships’ safe return to port requirements agreed 

The Sub-Committee agreed to the draft Explanatory Notes for safe return to port and orderly evacuation and abandonment after a fire or flooding casualty, and the associated draft MSC circular, with a view to approval at MSC 111. 

The SOLAS regulations for safe return to port (SRtP) for passenger ships, which came into effect in 2010, have wide implications for the design, testing and operation of passenger ships, but the industry has found it challenging to put into practice.  

The original Explanatory Notes in 2010 (MSC.1/Circ.1369) aimed to help ensuring the SRtP requirements were applied consistently, in particular on verification and approval of compliance by Administrations. Sixteen years later, a lack of uniform implementation across the passenger ship sector, and many points needing further clarification, led to the necessary revision process. 

The draft revision of the Explanatory Notes expands the scope of the guidance beyond that of MSC.1/Circ.1369 to cover the full life cycle of passenger ships – including design and verification, testing and operational aspects, including the following: 

  • aspects to be addressed in the pre-contract/early project phase; 

  • design requirements and acceptance criteria for all SRtP and orderly evacuation and abandonment (OEA) systems 

  • SRtP assessment process 

  • tests and trials 

  • documentation, verification and approval 

  • on-board documentation for SRtP and OEA 

  • high-level operational aspects 

The draft revision of the Explanatory Notes will be submitted to MSC 111 for approval. 

The Sub-Committee agreed to provide the draft Explanatory Notes to the Sub-Committee on Human Element, Training and Watchkeeping (HTW 13) and the Sub-Committee on Implementation of IMO Instruments (III 12) and invite them to consider whether existing instruments under their remit need to be amended accordingly. 

Roadmap on the development of ECRAM performance standards agreed 

The Sub-Committee agreed to the road map for developing Engine Control Room Alert Management (ECRAM) performance standards, as an independent instrument from Bridge Alert Management standards (resolution MSC.302(87)). These will define how alarms in a ship’s engine control room (ECR) are designed and maintained to ensure operations under normal and emergency conditions.  

The roadmap includes finalization of the draft ECRAM performance standards at SDC 14, for consideration and adoption by MSC 114 in 2028. A Correspondence Group was established to progress the work intersessionally. 

Draft amendments to the 2009 MODU Code agreed 

The Sub-Committee agreed to the draft amendments to the Code for the Construction and Equipment of Mobile Offshore Drilling Units (MODU Code, 2009), specifically on Chapter 6 on Machinery and Electrical Installations in Hazardous Areas, related to emergency conditions due to drilling operations. 

The agreed amendments require that, during emergencies, only essential and well-protected equipment continues to operate, reducing fire and explosion risks. Equipment exposed to open areas must be suitable for potentially hazardous conditions, while equipment inside enclosed spaces is allowed to keep running only if extra safety protections are in place, and critical lighting, alarms, and communication systems are always kept available to protect people and the installation. 

The Sub-Committee agreed to apply the amendments only to new MODUs constructed on or after 1 January 2027, and finalized the draft amendments and its associated draft MSC resolution, with a view to adoption at MSC 111. 

Draft guidelines on remote inspection techniques for ESP surveys agreed 

The Sub-Committee agreed to the draft guidelines on the use of remote inspection techniques (RIT), with a view to approval by MSC 111, in conjunction with the adoption of the associated draft amendments to the 2011 ESP Code to allow the use of RIT in ESP Code surveys. 

These guidelines provide guidance for the safe use remote inspection tools, such as drones or robotic devices, to help surveyors inspect hard-to-reach parts of a ship’s structure during inspections required by the International Code on the Enhanced Programme of Inspections During Surveys of Bulk Carriers and Oil Tankers (2011 ESP Code). 

Draft amendments to the 2011 ESP Code agreed and related instruments 

The Sub-Committee agreed to draft an amendment to the 2011 ESP Code to harmonize the fracture detection procedures between bulk carrier and oil tankers by including the option for “other equivalent means” to paragraph 5.4.2 of both parts A and B of Annex A. 

The draft amendments will be submitted to MSC 111 (May 2026) for Approval in Principle and is planned to be adopted by MSC 114 (2028). 

The Sub-Committee agreed to related draft amendments to the Technical provisions for means of access for inspections (resolution MSC.133(76), as amended), with a view to approval by MSC 111 and adoption by MSC 112. 

Propulsion and steering systems 

Revision of SOLAS Chapters II-1 (Part C) and V, and related instruments regarding steering and propulsion requirements 

The Sub-Committee continued its work to develop draft amendments to SOLAS Chapters II-1 (Part C) and V regarding ship steering and propulsion systems, focusing on application dates, format, ship steering performance and steering system failure tolerance, among other issues.  

The Sub-Committee agreed in principle to the proposed amendments and that the new requirements will be goal-based and apply to all steering and propulsion systems, both existing conventional systems and modern combined steering and propulsion systems. A working group is expected to be established at its next session (SDC 13) to continue discussions. 

Draft new international ship manoeuvrability standards (ISSM)  

The Sub-Committee further discussed the ongoing development of draft new international ship manoeuvrability standards, intended to be applicable to new ships subject to the new goal-based SOLAS regulations.  

The Sub-Committee agreed in principle to proposed principles for the establishment ISSM; however, further work was needed for their development.  

The Sub-Committee reiterated the invitation to Member States and international organizations to continue submitting relevant trial data to assist in developing robust standards, which will apply to both traditional and non-traditional propulsion and steering systems. 

Work on the draft revision of SOLAS Chapter II-1, aimed at addressing both traditional and non-traditional propulsion and steering systems,  is underway. According to the roadmap agreed at SDC 11, the revised chapter is planned to enter into force on 1 January 2032, together with the new standards, both of which are expected to be adopted in 2029 (MSC 116).  

Amendments to the Fire Safety Systems Code  

The Sub-Committee considered draft amendments to chapter 15 of the International Code for Fire Safety Systems (FSS Code) regarding nitrogen systems, and discussed the review of Guidelines for the application of plastic pipes on ships (resolution A.753(18)).

The Sub-Committee agreed to establish a working group during its next session (SDC 13) to continue discussions.