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MARINE & OFFSHORE DIVISION MANAGEMENT

L-C&R

SDC 6 - 4 TO 8 FEBRUARY 2019

MAJOR OUTCOMES OF THE 6TH SESSION OF THE SUB-COMMITTEE ON SHIP DESIGN

AND CONSTRUCTION

SUMMARY

The 6th session of the Sub-Committee on Ship Design and Construction (SDC 6), was held at IMO

Headquarters from 4 to 8 February 2019.

Revised SOLAS regulation II-1/3-8 and associated guidelines (MSC.1/CIRC.1175) and new

guidelines for safe mooring operations for all ships (item 3)

SDC 6 agreed to :

• draft amendments to SOLAS regulation II-1/3-8, with a view to submission to MSC 101 for

approval ;

• draft Guidelines on the design of mooring arrangements and the selection of appropriate

mooring equipment and fittings for safe mooring and the associated draft MSC circular,

with a view to submission to MSC 101 for approval ;

• draft Guidelines for inspection and maintenance of mooring equipment including lines

and the associated draft MSC circular, with a view to submission to MSC 101 for approval

;

• draft Revised guidance on shipboard towing and mooring equipment and the associated

draft MSC circular, i.e. MSC.1/Circ.1175/Rev.1, with a view to submission to MSC 101 for

approval.

Review SOLAS chapter II-1, parts B-2 TO B-4, to ensure consistency with parts B and B-1 with

regard to watertight integrity (Item 4)

SDC 6 agreed to :

• draft Amendments to SOLAS chapter II-1, parts B-2 to B-4, with a view to approval by MSC

101 ;

• draft amendments to regulation II-1/7-2.5 to require openings in locations immersed in

the final and/or intermediate stages of flooding to be watertight for passenger ships, with

a view to approval by MSC 101 ;

• draft amendments to SOLAS regulation II-1/7-2.5.5 to clarify that some of the listed

openings were allowed to be opened during navigation in accordance with SOLAS

regulations II-1/22 to 24, and were not considered as openings in the damage stability

calculations, with a view to approval by MSC 101;

• draft amendments to SOLAS regulation II-1/17.1 to align with the internal watertight

subdivision arrangements necessary for compliance with the stability requirements in

parts B-1 and B-2 ;

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• draft amendments to SOLAS regulation 12.6.1 on the the requirement for remotely

controlled valves ;

• draft amendments to SOLAS regulations II-1/13.5.1 and II-1/13.6 on remote operating

positions for all power-operated doors

• draft amendments to regulation II-1/22.6 which requires watertight hatches to be kept

closed during navigation.

Finalization of second generation intact stability criteria (item 5)

Important progress was achieved, with a view to finalization at SDC 7 of the following guidelines :

• Draft interim guidelines on the specification of direct stability assessment procedures ;

• Draft interim guidelines on the preparation of operational limitations and operational

guidance ;

• Draft interim guidelines on vulnerability criteria for the second generation of intact

stability criteria.

SDC 6 agreed to the structure of the draft guidelines and the consolidation of all three guidelines

under a single set of guidelines, given the fact that they were all connected and cross-referencing

to one another.

Mandatory instrument and/or provisions addressing safety standards for the carriage of more

than 12 industrial personnel on board vessels engaged on international voyages (item 6)

Despite the hard work in the relevant Working group, it was not possible to finalize the IP Code

during the given timeframe. This task has been forwarded to a new Correspondence group.

SDC 6 agreed that there was a need for thresholds in some of the regulations, and that the

thresholds used in the SPS Code, carriage of not more than 60, more than 60 but not more than

240 and more than 240 persons on board should, whenever possible, be applied for the relevant

regulations in the draft Code.

SDC 6 decided to refer sections on dangerous goods to the CCC and PPR Sub-Committee for their

advice.

Amendments to the 2011 ESP code (Item 7)

SDC 6 agreed to the draft consolidated text of the ESP Code, and the associated draft Assembly

resolution, for submission to MSC 101 for approval and subsequent adoption by A 31

Unified interpretation to provisions of IMO safety, security, and environment-related

conventions (item 9)

SDC 6 agreed to :

• draft amendments to the unified interpretations of the 2008 Intact Stability Code

(MSC.1/Circ.1537), for submission to MSC 101 for approval with a view to dissemination

as MSC.1/Circ.1537/Rev.1 ;

• draft amendments to annex to Unified interpretations relating to the Protocol of 1988

relating to the International Convention on Load Lines, 1966 (MSC.1/Circ.1535/Corr.1),

draft Unified interpretations of the 2008 IS Code (MSC.1/Circ.1537) and draft Unified

interpretation of SOLAS Chapter II-1 (MSC.1/Circ.1539) for submission to MSC 101 for

approval ;

• draft MSC circular on Unified interpretation of SOLAS regulations II-1/22-1 and II-

2/21.4.13 regarding safe return to port requirements for flooding detection systems, for

submission to MSC 101 for approval.

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Item 3 - Revised solas regulation II-1/3-8 and associated guidelines (MSC.1/CIRC.1175) and new

guidelines for safe mooring operations for all ships

SDC 5 re-established the Correspondence Group on Safe Mooring Operations. It wa instructed to :

• further develop the draft new Guidelines on the design of mooring arrangements and the

selection of appropriate mooring equipment and fittings for safe moor

• further develop the draft Guidelines for inspection and maintenance of mooring

equipment including lines,

• further develop the draft Revised guidance on shipboard towing and mooring equipment

(MSC.1/Circ.1175),

• further consider any consequential amendments to relevant IMO instruments.

SDC 6 had for its consideration the following main outstanding issues :

• application and inclusion of the human-centred design approach;

• requirement for load monitoring equipment;

• approval of ships' towing and mooring arrangement plans; and

• definitions for "Working Load Limit (WLL)" and "Line Design Break Force (LDBF)".

Application and inclusion of the human-centred design approach

SDC 5 agreed in principle to the draft amendment to SOLAS regulation II-1/3-8, including

paragraph 7, as follows:

"7 For ships of 3,000 gross tonnage and above the design of the mooring arrangement

and the selection of appropriate mooring equipment including lines shall be based on

guidelines developed by the Organization**[, applying a human-centred design

approach]."

The delegation of the Bahamas, having advised the Sub-Committee that they were not able to

accept the draft amendment including the undefined term "human-centred design approach",

reserved their position on this issue, agreed that the words "applying a human-centred design

approach" should be kept in square brackets.

The expression "applying a human-centred design approach" may not constitute a verifiable or

objective standard. The term "human-centred design" is used in ISO standard 13407:1999

"Human-centred design processes for interactive systems", which was later replaced by ISO 9241-

210:2010 "Ergonomics of human-system interaction – Part 210: Human-centred design for

interactive systems". It is a standard for the development of interactive systems. Only few

provisions might be suitable for designing the arrangement of mechanical equipment. It requires

participation of users in the design stage and, ideally, throughout equipment life.

The Correspondence Group on Safe Mooring Operations, established at SDC 5, did not consider

the provisions related to "a human-centred design approach" in the draft Guidelines on the

design of mooring arrangements and the selection of appropriate mooring equipment and fittings

for safe mooring.

Finally, SDC 6 agreed not to include any reference on human-centred design in draft SOLAS

regulation II-1/3-8.7 or the Design Guidelines as it would not constitute a verifiable standard

against which appraisal of mooring arrangement or calculation/approval of the mooring line

strength could be carried out.

Requirement for load monitoring equipment

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SDC 6 agreed not to include provisions requiring load monitoring equipment. It considered as

doubtful, in the absence of relevant information from manufacturers and without the necessary

tools which could be used consistently, that the measurement of mooring line loading patterns

for the assessment of the reduction in the design life and strength of mooring lines could be

achieved by ships' personnel.

Degradation of the lines is caused not only by the loads acting on the lines but by various factors,

such as corrosion. Therefore, replacement of the lines, depending on their wear and tear state, is

considered more effective than monitoring the loads acting on the lines to ensure safety of

mooring operation. In other words, the essential issue is the implementation of the Inspection

and maintenance guidelines.

Approval of ships' towing and mooring arrangement plans

Some delegations raised the issue of whether or not the approach to be taken in devising new or

amending instruments on mooring and towing arrangements would require ships' towing and

mooring arrangement plans to be approved by the Administration. Such a requirement was not

retained.

Use and definitions for strength requirements of mooring lines and equipment

Divergent views were expressed on the use and definitions for strength requirements of mooring

lines and equipment, such as Ship Design Minimum Breaking Load (MBLSD), Working Load Limit

(WLL), the relation between SWL and MBL and others.

In the MEG4, WLL is used in order to calculate the ship design MBL. When the ship design MBL is

calculated using the WLL, WLL can be used as operational limit value. However, since WLL is

determined based on environmental condition, the operational limit can be set by the

environmental condition.

Here are the provisions retained in the final draft :

5.2.8 Load limits

5.2.8.1 Notwithstanding the definitions in paragraph 2.1, LDBF of mooring lines

made of nylon should be tested under wet and spliced conditions.

5.2.8.2 All components of a ship's mooring system, within defined tolerances,

should be selected based on MBLSD.

5.2.8.3 When selecting lines, the LDBF should be 100% to 105% of the MBLSD.

5.2.8.4 The WLL of mooring lines should be used as user operating limiting values,

not to be exceeded. The WLL is expressed as a percentage of MBLSD and should

be used as a limiting value in operational mooring analyses. Steel wires have a

WLL of 55% of MBLSD and all other cordage (synthetic) have a WLL of 50% of the

MBLSD.

Draft amendments to SOLAS regulation II-1/3-8

SDC 6 agreed to the draft amendments to SOLAS regulation II-1/3-8, with a view to submission to

MSC 101 for approval.

It agreed :

• to refer to "occupational safety" in place of "human-centred design approach” ;

• to insert the new requirement of "The design of mooring arrangements and rationale of

selection of the mooring equipment including lines shall be documented and kept

onboard" in SOLAS, but without specifying any type or details of such a document.

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Draft new guidelines on the design of mooring arrangements

SDC 6 agreed to the draft Guidelines on the design of mooring arrangements and the selection of

appropriate mooring equipment and fittings for safe mooring and the associated draft MSC

circular, with a view to submission to MSC for approval, in conjunction with the adoption of the

draft amendments to SOLAS regulation II-1/3-8

Noting that human element was one of the principal considerations in the development of the

draft new Guidelines, one paragraph under section 1 regarding the application of principles of

ergonomics and usability was included.

A new section for reference in the draft Guidelines takes into account principles for effective

mooring arrangements included in appropriate industry guidance.

Draft guidelines for inspection and maintenance

SDC 6 agreed to the draft Guidelines for inspection and maintenance of mooring equipment

including lines and the associated draft MSC circular, with a view to submission to MSC for

approval,

SDC 6 considered that familiarization and training related to safe use of mooring equipment and

fittings would be more appropriately addressed by another IMO body. Hence, it decided to

forward matters regarding familiarization and training to MSC for consideration and action, as

appropriate, taking into account that such issues are out of the scope of the work of the current

output.

Draft revised guidance on shipboard towing and mooring equipment (MSC.1/Circ.1175)

SDC 6 agreed to the draft Revised guidance on shipboard towing and mooring equipment and the

associated draft MSC circular, i.e. MSC.1/Circ.1175/Rev.1, with a view to submission to MSC for

approval, in conjunction with the adoption of the draft amendments to SOLAS regulation II-1/3-8

It agreed to clarify that sections 2 and 3 of appendix A provide minimum value of ship design

Minimum Breaking Load (MBLSD) and MBLSD should be determined by a ship designer.

The draft Revised guidance should be applicable to ships constructed on or after the date of entry

into force of revised SOLAS regulation II-1/3-8. Meanwhile, the Guidance on shipboard towing and

mooring equipment (MSC.1/Circ.1175) will continue to be applicable to ships constructed on or

after 1 January 2007 but before the aforementioned date of entry into force.

Consequential amendments to relevant IMO instruments

SDC 6 noted that there might be some more consequential amendments to other IMO

instruments, and therefore requested the IMO Secretariat to take action, as appropriate.

The following three IMO instruments were identified as those which may be amended

consequentially :

.1 Survey guidelines under the harmonized system of survey and certification (HSSC), 2015

(resolution A.1104(29));

.2 List of certificates and documents required to be carried on board ships, 2013

(FAL.2/Circ.127-MEPC.1/Circ.817-MSC.1/Circ.1462);

.3 List of codes, recommendations, guidelines and other safety- and security-related non-

mandatory instruments (MSC.1/Circ.1371 and addenda 1 and 2).

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Nevertheless, this task on the SDC agenda is now considered to be fulfilled.

Item 4 - Review SOLAS chapter II-1, parts B-2 TO B-4, to ensure consistency with parts B and B-1

with regard to watertight integrity

Relying on the work made by the dedicated correspondence group set up by SDC 5, SDC 6 had for

objective to :

• finalize the draft amendments to regulation II-1/7-2.5.2 ;

• consider amendments to regulation II-1/12.6.1 in relation to the location and operation of

the collision bulkhead valve;

• consider the draft application criteria for the amendments;

• revise MSC.1/Circ.1464/Rev.1.

SDC 6 agreed to the draft Amendments to SOLAS chapter II-1, parts B-2 to B-4, and SOLAS

regulation 7-2 of part B-1, with a view to approval by MSC 101.

Amendments to SOLAS regulation 7-2.5

SDC 6 considered SOLAS regulations II-1/7-2.5 and II-1/17.1 and agreed there was a significant

inconsistency regarding the treatment of openings in bulkheads that were considered watertight

in the damage stability calculations and were located above the bulkhead deck.

Regulation II-1/7-2.5.2.1 only requires these doors to be watertight if immersed at the final

equilibrium stage of flooding, but not at intermediate stages of flooding beyond the final

equilibrium angle or in the residual range of stability. Regulation II-1/17.1, together with

MSC/Circ.541, although generally considered legacy provisions, require these doors to be

watertight in all stages of flooding but are somewhat unclear regarding the residual range of

stability.

As SOLAS regulation II-1/17 is only applicable to passenger ships and, therefore, the amendments

to resolve the inconsistency should only apply to passenger ships.

Thus, SDC 6 agreed to revise SOLAS regulation II-1/7-2.5 to require openings in locations

immersed in the final and/or intermediate stages of flooding to be watertight for passenger ships.

This was accomplished by making regulation II-1/7-2.5.2.1 applicable only to cargo ships and

duplicating the SOLAS regulation II-1/7-2.5.2.1 text as a new SOLAS regulation II-1/7-2.5.3.4

applicable only to passenger ships.

Regulation 7-2

Calculation of the factor si

5.2 The factor si is to be taken as zero in those cases where the final waterline, taking into

account sinkage, heel and trim, immerses:

.1 for cargo ships, the lower edge of openings through which progressive flooding

may take place and such flooding is not accounted for in the calculation of factor

si. Such openings shall include air-pipes, ventilators and openings which are closed

by means of weathertight doors or hatch covers; and

.2 any part of the bulkhead deck in passenger ships considered a horizontal

evacuation route for compliance with chapter II-2; and

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.3 for passenger ships subject to the provisions of regulation 1.1.1.1 and

constructed before 1 January 2024, the lower edge of openings through which

progressive flooding may take place and such flooding is not accounted for in the

calculation of factor si. Such openings shall include air-pipes, ventilators and

openings which are closed by means of weathertight doors or hatch covers.

5.3 The factor si is to be taken as zero if, taking into account sinkage, heel and trim, any of

the following occur in any intermediate stage or in the final stage of flooding:

(…)

.4 for passenger ships constructed on or after 1 January 2024, immersion of the

lower edge of openings through which progressive flooding may take place and

such flooding is not accounted for in the calculation of factor si. Such openings

shall include air-pipes, ventilators and openings which are closed by means of

weathertight doors or hatch covers.

SDC 6 also agreed to an amendment to SOLAS regulation II-1/7-2.5.5 to clarify that some of the

listed openings were allowed to be opened during navigation in accordance with SOLAS

regulations II-1/22 to 24, and were not considered as openings in the damage stability

calculations.

5.5 Except as provided in paragraph 5.3.1, openings closed by means of watertight

manhole covers and flush scuttles, remotely operated sliding watertight doors, side

scuttles of the non-opening type as well as watertight access doors and watertight hatch

covers required to be kept closed at sea during navigation in accordance with regulations

22 to 24 need not be considered.

Amendments to SOLAS regulation 17

Taking into account the agreed amendments to SOLAS regulation II-1/7-2.5, SDC 6 agreed to

amend SOLAS regulation II-1/17.1 to align with the internal watertight subdivision arrangements

necessary for compliance with the stability requirements in parts B-1 and B-2.

A new SOLAS regulation II-1/17.3 was added to address doors in internal watertight subdivision

arrangements above the bulkhead deck that were immersed only in the required range of positive

stability for any damage cases contributing to the attained subdivision index A. These doors,

which may be hinged or sliding, shall be capable of preventing the passage of water. In addition,

these doors may remain open provided they can be remotely closed from the navigation bridge

and are always ready to be immediately closed.

Regulation 17

Internal watertight integrity of passenger ships above the bulkhead deck

1 For passenger ships subject to the provisions of regulation 1.1.1.1 and constructed

before 1 January 2024, the Administration may require that all reasonable and practicable

measures shall be taken to limit the entry and spread of water above the bulkhead deck.

Such measures may include partial bulkheads or webs. When partial watertight bulkheads

and webs are fitted on the bulkhead deck, above or in the immediate vicinity of

watertight bulkheads, they shall have watertight shell and bulkhead deck connections so

as to restrict the flow of water along the deck when the ship is in a heeled damaged

condition. Where the partial watertight bulkhead does not line up with the bulkhead

below, the bulkhead deck between shall be made effectively watertight. Where openings,

pipes, scuppers, electric cables etc. are carried through the partial watertight bulkheads

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or decks within the immersed part of the bulkhead deck, arrangements shall be made to

ensure the watertight integrity of the structure above the bulkhead deck.

12 For ships constructed on or after 1 January 2024, The Administration may require that

all reasonable and practicable measures shall be taken to limit the entry and spread of

water above the bulkhead deck. Such measures may include partial bulkheads or webs.

the internal watertight subdivision arrangements to limit the entry and spread of water

above the bulkhead deck shall be in accordance with the design arrangements necessary

for compliance with the stability requirements in parts B-1, and B-2 if applicable. When

partial watertight bulkheads and webs are fitted on the bulkhead deck, above or in the

immediate vicinity of watertight bulkheads, they shall have watertight shell and bulkhead

deck connections so as to restrict the flow of water along the deck when the ship is in a

heeled damaged condition. Where the partial watertight bulkhead does not line up with

the bulkhead below, the bulkhead deck between shall be made effectively watertight.

Where openings, pipes, scuppers, electric cables, etc. are carried through the partial

internal watertight bulkheads or decks within the immersed part of the bulkhead deck,

arrangements boundaries that are immersed at any intermediate or final stage of flooding

in damage cases that contribute to the attained subdivision index A, arrangements shall

be made to ensure their watertight integrity of the structure above the bulkhead deck.*

* Refer to the Guidance notes on the integrity of flooding boundaries above the bulkhead

deck of passenger ships for proper application of regulations II-1/8 and 20, paragraph 1, of

SOLAS 1974, as amended (MSC/Circ.541, as may be amended).

3 For ships constructed on or after 1 January 2024, doors in internal watertight

subdivision arrangements above the bulkhead deck, and also above the worst

intermediate or final stage of flooding waterlines, shall be capable of preventing the

passage of water when immersed in the required range of positive stability for any

damage cases contributing to the attained subdivision index A. These doors may remain

open provided they can be remotely closed from the navigation bridge. They shall always

be ready to be immediately closed.

Amendments to SOLAS regulation 12.6.1

During the process of harmonizing the probabilistic damage stability regulations for both cargo

and passenger ships, the SDS Working Group concluded that "the principles for watertight spaces

and openings are similar for passenger ships and cargo ships and wherever possible the provisions

should be harmonized in the revised regulations". This has resulted in the current regulation 12,

which is now applicable to all ship types and which requires "screw-down" valves for all ships, but

also makes a provision for other valve types, such as butterfly valves, only on cargo ships.

The deletion of prescriptive collision bulkhead valve type and location requirements in regulation

II-1/12.6.1 was supported by a large majority but there were mixed views on the new

replacement text, i.e. "remotely controlled valve" or "valve with a positive means of closing from

a position above the bulkhead deck of passenger ships and the freeboard deck of cargo ships".

SDC 6 agreed to the requirement for remotely controlled valves and to retain some of the existing

restrictions regarding the location of the valves. The valve could be located on either the forward

or aft side of the collision bulkhead, provided the space on the aft side was not a cargo space.

A provision was also included to ensure that the valve was either fail safe or capable of being

closed manually from a position above the bulkhead deck of passenger ships and the freeboard

deck of cargo ships if the remote control system should fail.

In addition, a new provision was added that the valve shall be normally closed.

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Regulation 12

Peak and machinery space bulkheads, shaft tunnels, etc.

6.12 For ships constructed on or after 1 January 2024, eExcept as provided in paragraph

6.23, the collision bulkhead may be pierced below the bulkhead deck of passenger ships

and the freeboard deck of cargo ships by not more than one pipe for dealing with fluid in

the forepeak tank, provided that the pipe is fitted with a screw-down valve remotely

controlled valve capable of being operated from above the bulkhead deck of passenger

ships and the freeboard deck of cargo ships., the valve being located inside the forepeak

at the collision bulkhead. The Administration may, however, authorize the fitting of this

valve on the after side of the collision bulkhead provided that the valve is readily

accessible under all service conditions and the space in which it is located is not a cargo

space. Alternatively, for cargo ships, the pipe may be fitted with a butterfly valve suitably

supported by a seat or flanges and capable of being operated from above the freeboard

deck. The valve shall be normally closed. If the remote control system should fail during

operation of the valve, the valve shall close automatically or be capable of being closed

manually from a position above the bulkhead deck of passenger ships and the freeboard

deck of cargo ships. The valve shall be located at the collision bulkhead on either the

forward or aft side, provided the space on the aft side is not a cargo space. All The valves

shall be of steel, bronze or other approved ductile material. Valves of ordinary cast iron or

similar material are not acceptable.

Amendments to SOLAS regulation 13

IACS proposed amendments to SOLAS regulations II-1/13.5.1 and II-1/13.6, which currently limit

the remote operating positions for all power-operated sliding doors to the navigation bridge and

the location above the bulkhead deck where hand operation is provided. The proposal is to

extend the remote operating positions to other locations in light of the requirement in SOLAS

regulation II-2/23.6 and the available computer technologies

SOLAS regulation II-1/13.5.1 states:

"Watertight doors, except as provided in paragraph 9.1 or regulation 14, shall be power-

operated sliding doors complying with the requirements of paragraph 7 capable of being

closed simultaneously from the central operating console at the navigation bridge in not

more than 60 s with the ship in the upright position."

In addition, SOLAS regulation II-1/13.6 states:

"All power-operated sliding watertight doors shall be provided with means of indication

which will show at all remote operating positions whether the doors are open or closed.

Remote operating positions shall only be at the navigation bridge as required by

paragraph 7.1.5 and at the location where hand operation above the bulkhead deck is

required by paragraph 7.1.4."

The above regulations might be interpreted so that the requirements prescribed therein refer to

the mandatory remote control positions to operate the watertight doors in case of damage, but

they do not prohibit the installation of additional remote controls associated with other safety

systems. It is understood that systems associated with such remote controls do not impair the full

functionality of the watertight doors' controls as required by SOLAS regulations II-1/13.5.1 and II-

1/13.6.

Moreover, it is noted that SOLAS regulation II-2/23.6 "Control and monitoring of safety systems",

which has been in force since 1 July 2010, requires watertight door controls to be placed in the

safety centre. The safety centre may not be on the navigating bridge. The requirements of SOLAS

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regulation II-1/13.6 interpreted as described in paragraph 2 above would prevent the controls

from being placed in the safety centre, which is not considered reasonable.

Amendments were accepted with the exception of the proposal to allow the potential fitting of

additional watertight door remote operating positions.

Regulation 13 Openings in watertight boundaries below the bulkhead deck in passenger

ships

87.1 A central operating console for all power-operated sliding watertight doors shall be

located in the safety centre in accordance with regulation II-2/23. If the safety centre is

located in a separate space adjacent to the navigation bridge, a central operating console

shall also be located on the navigation bridge. The central operating console(s) at the

navigation bridge shall have a "master mode" switch with two modes of control: a "local

control" mode which shall allow any door to be locally opened and locally closed after use

without automatic closure, and a "doors closed" mode which shall automatically close any

door that is open in not more than 60 s with the ship in an upright position. The “doors

closed” mode shall automatically close any door that is open. The "doors closed" mode

shall permit doors to be opened locally and shall automatically re-close the doors upon

release of the local control mechanism. The "master mode" switch shall normally be in

the "local control" mode. The "doors closed" mode shall only be used in an emergency or

for testing purposes. Special consideration shall be given to the reliability of the "master

mode" switch.

Amendments to SOLAS regulation 22.6

SDC 6 agreed to amend regulation II-1/22.6 which requires watertight hatches to be kept closed

during navigation, with the option that allowed these hatches to be opened for limited access if

permitted by the Master.

67 For ships constructed on or after 1 January 2024, Ggangway, cargo and fuelling ports

fitted below the bulkhead deck of passenger ships and the freeboard deck of cargo ships

and all watertight hatches, shall be effectively closed and secured watertight before the

voyage commences, and shall be kept closed during navigation. However, the master may

permit a watertight hatch to be opened during navigation for a limited period of time

sufficient to permit passage or for access. It shall then be closed.

Application of the draft amendments

Draft amendments address a variety of issues and, accordingly, the new provisions will have a

range of impacts. Some of the regulation changes are more significant and will impact ship design

arrangements whereas others are relatively minor text clarifications, corrections or in several

cases removal of outdated requirements.

For the amendments that will potentially impact ship design arrangements, application is limited

to new ships, i.e. ships built after the anticipated 1 January 2024 entry-into-force date of the draft

amendments.

Item 5 - Finalization of second generation intact stability criteria

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The development of the second generation intact stability criteria started at the SLF Sub-

Committee in 2002, mainly with the following three objectives:

• First, to authorize sufficient intact stability of large cruise vessels which may not easily

comply with the weather criterion.

• Second, facilitation for the use of state-of-the-art technologies such as time domain

simulation tools as an alternative to prescriptive intact stability criteria.

• Third, prevention of a severe accident similar to that of a C11 class containership due to

parametric rolling in head waves in 1998.

The IMO is trying to develop intact stability criteria for the following dynamic stability situations:

• Parametric rolling (excessive roll in head seas)

• Dead ship conditions (when large roll is possible when the stabilising effects of speed are

removed)

• Surf riding/broaching (typically in following seas)

• Excessive accelerations (resulting in sudden large angle roll motions)

• Pure loss of stability on a wave crest (ship loses buoyancy because it is effectively

stationary on the crest and the water profile is different from design i.e. level waterline)

The aim of the IMO is to have some consistent criteria against which ships can be tested to

identify whether they are susceptible to any of the above intact stability phenomena. A pass at

the simplest level (level 1) will mean that there is no need to progress to the more complex

calculation at level 2. However, if level 2 is required and not passed then the vessel is subject to

further complex studies such as direct stability assessment techniques or operational limitations

and/or operator guidance.

SDC 6 had for its consideration :

• draft Guidelines for the specification of direct stability assessment ;

• draft Guidelines for the preparation and approval of operational limitations and

operational guidance ;

• draft Guidelines on vulnerability criteria for the second generation of intact stability

criteria.

Draft interim guidelines on the specification of direct stability assessment procedures

Definition was given to "direct assessment procedures", "assumed situation" and "nominal ship

forward speed", and re-defined "design situation". The "acceptance criteria" on maximum roll

amplitude was re-drafted. The "design scenarios" and the "extrapolation procedures" in the

form of a list were re-structured.

An important progress was achieved by the Expert Group, with a view to finalization at SDC 7,

pending minor improvements, clarifications and edits that a new correspondence group may

recommend.

Draft interim guidelines on the preparation of operational limitations and operational guidance

Two new paragraphs were added under the section "General principles" establishing a connection

with the draft interim guidelines for direct stability assessment and highlighting the application of

the draft guidelines for any loading condition. A new paragraph was included, clarifying the cases

where too many sailing conditions in too many sea states should be avoided for a certain loading

condition under the section "Acceptance of operational measures". The text under the section

"Probabilistic operational guidance" and modified the stability failure rate has been simplified.

12

The Plenary noted the progress made in developing the draft interim guidelines for the

preparation of operational limitations and operational guidance, in the view of finalization at SDC

7.

Draft interim guidelines on vulnerability criteria for the second generation of intact stability

criteria

The Expert group

• re-phrased the section "Application" under each of the failure modes for clarifying each

condition of loading a ship that met neither of the standards contained in levels 1 and 2

vulnerability criteria

• included a provision for a free surface correction for all relevant failure modes;

• provided an exception for ships with extended low weather decks and noted that similar

exceptions were required in the draft interim guidelines for direct stability assessment,

and the draft interim guidelines on the preparation of operational limitations and

operational guidance.

The Expert Group further developed the draft interim guidelines, and SDC 6 acknowledged the

progress made with a view to finalization at SDC 7.

Regulatory relationship between the current weather criterion and the draft dead ship condition

criteria

An alternative to the application of the weather criterion for the dead ship failure could currently

only be addressed through either the equivalent provision in SOLAS or through MSC.1/Circ.1200

on Interim guidelines for alternative assessment of the weather criterion.

A thorough discussion occurred as to the validity of dead ship condition, and the regulatory

relationship between the existing weather criterion and the draft dead ship condition criteria.

Following the discussion, the vast majority agreed that the draft dead ship condition criteria

should not be considered as an alternative for the existing weather criterion on the 2008 IS Code.

Therefore, a draft text has been included in the preamble/introductory section to be developed in

order to highlight this;

Structure of the draft guidelines and consolidation of all three guidelines as a single set

SDC 6 agreed to the structure of the draft guidelines and the consolidation of all three guidelines

under a single set of guidelines, given the fact that they were all connected and cross-referencing

to one another.

Item 6 - Mandatory instrument and/or provisions addressing safety standards for the carriage

of more than 12 industrial personnel on board vessels engaged on international voyages

MSC 96 had agreed that:

.1 a new chapter to SOLAS should be developed solely for the carriage of more than 12

industrial personnel;

13

.2 the above new chapter should be supported by a new code, which could include

elements of the 2008 SPS and 2000 HSC Codes, as appropriate;

.3 the number of industrial personnel being transported should be the basis for applying

the new SOLAS requirements.

MSC 97 had adopted the Interim recommendations on the safe carriage of more than 12

industrial personnel on board vessels engaged on international voyages (resolution MSC.418

(97)), and endorsed the view that the proposed definitions of industrial personnel and offshore

industrial activities should be the basis for the development of the mandatory instrument.

MSC 99 agreed that:

.1 the aggregated total maximum number of passengers, industrial personnel and special

personnel which may be carried on board in order not to require compliance with the

new code should be 12;

.2 the application of the new SOLAS chapter [XV] and the new code should be limited to

ships holding Cargo Ship Safety Certificates.

MSC 99 had noted the principles and decisions that had been considered by SDC 5 as the basis for

the development of the draft new SOLAS chapter XV and the draft new code.

The main task of SDC 6 was to was instructed to further develop the draft IP Code, and, in

particular, consider provisions in the draft Code addressing the carriage of dangerous goods and

hazardous and noxious liquid substances

IP Code

Preamble and Part I – General - Definitions

Recalling the draft definition of "industrial personnel" as provided in the draft new SOLAS chapter

XV, SDC 6 agreed that these words were not necessary and should be deleted. It was also agreed

that there must be consistency in the definitions used in SOLAS and the IP Code

Regarding the definition of "offshore industrial activities", it was agreed to amend the definition

currently used in the Interim recommendations on the safe carriage of more than 12 industrial

personnel on board vessels engaged on international voyages (resolution MSC.418(97)) to better

reflect the activities carried out by ships to which the new Code would apply.

Part II – Goals and functional requirements

There are three chapters within part II, namely, "Design, systems and equipment", "Industrial

Personnel" and "Safe transfer of personnel".

Part II of the IP Code was finalized. However, it might be necessary to revisit the functional

requirements to ensure alignment with the regulations at a later stage.

Part III – Regulations

SDC 6 agreed that using an aggregated number of passengers, special personnel and industrial

personnel to invoke the application of the IP Code had caused confusion and ambiguity. It was

agreed that there must be consistency in the definitions used in SOLAS and the IP Code

The decision of MSC 99 that "the aggregated total maximum number of passengers, industrial

personnel and special personnel which may be carried on board in order not to require

14

compliance with the new code should be 12 was questioned by some members. In their view,

prior discussions and work have been related to the carriage of more than 12 industrial personnel,

not an aggregated number of persons, and this should not be changed.

As ships to which the draft Code applied would have cargo ship certification in accordance with

chapter I of SOLAS as a "base-line", draft regulations that were covered by the cargo ship

regulations in SOLAS or the HSC Code were deleted. Only additional requirements to the cargo

ship requirements of SOLAS and the HSC Code were included in the draft regulations.

SDC 6 agreed that there was a need for thresholds in some of the regulations, and that the

thresholds used in the SPS Code, carriage of not more than 60, more than 60 but not more than

240 and more than 240 persons on board should, whenever possible, be applied for the relevant

regulations in the draft Code. It was also agreed to align the provisions of the draft Code with

those of the SPS Code.

For high-speed craft, these thresholds should be used to the extent possible.

Despite the hard work in the relevant Working group, it was not possible to finalize the IP Code

during the given timeframe. This task has been forwarded to a new Correspondence group.

Carriage of dangerous goods

The draft of the goals, functional requirements and regulations need to apply to all types of ships

that are permitted to transport dangerous goods in accordance with the mandatory requirements

in SOLAS Chapter VII and hazardous substances in accordance with non-mandatory requirements

in Resolution A.1122(30) (OSV Chemical Code).

The carriage of IP on tankers, bulk and gas carriers is not a likely scenario. However, given that the

scope of the IP Code is cargo ships of 500 GT and upwards, not excluding any cargo ship, draft

goals, functional requirements and regulations to ensure the safety of industrial personnel if

carried on a tanker, bulk or gas carrier were developed.

SDC 6 decided to refer sections on dangerous goods to the CCC and PPR Sub-Committee for their

advice.

Following sections should be referred to the CCC Sub-Committee for consideration:

3.1.8.1 Carriage of dangerous goods in packaged form, in particular for consideration of

thresholds of number of persons in relation to the requirements of IMDG Code;

3.1.8.2 Carriage of dangerous goods in solid form in bulk, in relation to the applicability of

IMSBC Code to ships carrying industrial personnel;

3.1.8.4 Carriage of liquefied gases in bulk, in relation to the applicability of IGC Code to

ships carrying industrial personnel.

Following sections should be referred to the PPR Sub-Committee for consideration:

3.1.8.3 Carriage of dangerous liquid chemicals in bulk, in relation to the applicability of IBC

Code to ships carrying industrial personnel;

3.1.8.5 Transport and handling of dangerous chemicals in bulk on Offshore Support

Vessels, in relation to the requirements of the OSV Chemical Code to ships carrying

industrial personnel.

Application of SOLAS chapter XV and the IP Code to non-SOLAS ships

15

It was proposed by some delegates to extend the application of the new draft IP Code to include

non-propelled accommodation barges used in support of offshore units but that may or may not

be engaged on international voyages

Following discussion, the Plenary agreed not to expand the application of the draft IP Code to

non-SOLAS ships.

Item 7 - amendments to the 2011 ESP code

SDC 4 authorized the IMO Secretariat and IACS to prepare a draft consolidated text of the ESP

Code for consideration at SDC 6.

SDC 5 agreed to proceed with the development of the draft consolidated version of the ESP Code.

SDC 5 confirmed the understanding that all substantive provisions currently contained in the

footnotes of the 2011 ESP Code should be included in the main body of the new consolidated

text.

SDC 5 agreed that the draft consolidated version of the ESP Code should be finalized at SDC 6,

taking into account the related outcome of MSC 100, with a view to:

• preparing a draft Assembly resolution for adoption of the draft consolidated version of

the ESP Code, revoking resolutions A.744(18) and A.1049(27);

• subsequent submission to MSC 101, for endorsement, and final adoption at A 31.

MSC 99 approved the draft amendments to the 2011 ESP Code, prepared by SDC 5.

MSC 100, after having considered the draft amendments to the 2011 ESP Code decided to:

• hold the adoption of the draft amendments to the 2011 ESP Code in abeyance and invited

IACS to work together with the Secretariat intersessionally to prepare a revised set of

draft amendments to the Code, for submission to MSC 101 with a view to adoption;

• instruct the SDC 6 to ensure that the draft 2019 ESP Code, expected to be finalized by SDC

6 with a view to approval by MSC 101 and subsequent submission to A 31, includes the

aforementioned revised draft amendments to the 2011 Code.

The consolidated version of the 2019 draft ESP Code was to be finalized by SDC 6 for approval at

MSC 101, with a view to adoption by A 31 as the 2019 ESP Code, superseding the 2011 ESP Code,

as amended.

An associated SOLAS amendment would be prepared by SDC 6 to make the 2019 ESP Code

mandatory, for submission to MSC 101 for approval with a view to subsequent adoption at MSC

102, following the adoption of the 2019 ESP Code by A 31.

Hence, SDC 6 agreed to the draft consolidated text of the ESP Code, and the associated draft

Assembly resolution, for submission to MSC 101 for approval and subsequent adoption by A 31.

The Drafting group made editorial amendments to ensure that "shall/should" instead of "is to/are

to" were used throughout the draft consolidated version of the ESP Code, as appropriate.

SDC 5 had agreed to use the term "Administration" to refer to both the Administration and the

organization recognized by the Administration. Accordingly, subsequent references to

"Administration or organization recognized by the Administration" and "recognized organization"

were replaced by "Administration".

16

Noting that Administrations did not have exclusive surveyors and therefore, as a consequence of

the above, it was agreed to the deletion of the word "exclusive" from relevant paragraphs.

Item 8 - safety measures for non-SOLAS ships operating in polar waters

Over one-third of vessels operating in the Arctic and over half the vessels operating in the

Antarctic are ships not certified in accordance with SOLAS chapter I. As a consequence, the

provisions of the Polar Code do not currently apply to these vessels. Furthermore, in the Arctic

vessels not certified in accordance with SOLAS chapter I operate seven times more hours and

cover 15 times greater distances than all categories of ships certified in accordance with SOLAS

chapter I combined (based on 2015 AIS data).

MSC 98 had agreed to include theoutput "Safety measures for non-SOLAS ships operating in polar

waters" on the provisional agenda of MSC 99, with a view to taking a policy decision regarding the

scope of application of the second phase of work on the Polar Code, its mandatory or

recommendatory status and types of vessels to be addressed.

MSC 99 agreed:

• that any safety measures for non-SOLAS vessels should, in principle, apply to both Arctic

waters and the Antarctic area;

• when considering specific safety measures for each type of vessel, it was necessary to

consider the area of application on a case-by-case basis, as there was a possibility that

exemptions/exceptions may apply;

• that the types of vessels to be considered in the development of safety measures for non-

SOLAS ships operating in polar waters were fishing vessels, pleasure yachts above 300

gross tonnage not engaged in trade, and cargo ships below 500 gross tonnage down to

300 gross tonnage.

MSC 99, had instructed SDC 6 to develop recommendatory safety measures for the following

types of ships operating in polar waters:

• fishing vessels of 24 m in length and over, with a view to alignment with the 2012 Cape

Town Agreement;

• pleasure yachts above 300 gross tonnage (GT) not engaged in trade.

MSC 100 had endorsed these tasks.

Canada and New-Zealand proposed a set of guidelines for fishing vessels of 24 metres and over

operating in polar waters. The proposed Guidelines have been designed to align with the Cape

Town Agreement on the Safety of Fishing Vessels (2012)

The proposed Guidelines are designed to align with the Cape Town Agreement on the Safety of

Fishing Vessels (2012). The structure of the proposed Guidelines reflects that of the Cape Town

Agreement, with an additional chapter (XI) which sets out recommendations for other safety

measures that are beyond the scope of, or not provided for in, the Cape Town Agreement.

In response to the invitation of MSC 99, New Zealand has developed a proposed set of

recommendatory guidelines designed to improve the safety of pleasure yachts over 300 GT not

engaged in trade operating in polar waters. The Guidelines are intended to supplement existing

industry and/or national standards by providing additional guidance aimed at increasing safety

standards for yachts and their personnel in order to take account of the additional risk arising

from the climatic conditions of polar waters.

17

SDC 6 considered the Guidelines provided as a basis for initial discussion, with a view to their

further development and detailed discussion at SDC 7.

Therefore, having considered the above matters, SDC 6 established the Correspondence Group on

Safety Measures for Non-SOLAS Ships Operating in Polar Waters to, as a high priority, with a view

to finalization at SDC 7, further develop the draft guidelines for safety measures for fishing vessels

of 24 metres and over operating in polar waters, and to further develop the draft guidelines for

pleasure yachts of 300 GT and above not engaged in trade operating in polar waters,

Item 9 - Unified interpretation to provisions of IMO safety, security, and environment-related

conventions

SDC 6 agreed to the draft amendments to the unified interpretations in MSC.1/Circ.1535,

MSC.1/Circ.1537 and MSC.1/Circ.1539, for submission to MSC 101 for approval with a view to

dissemination as MSC.1/Circ.1535/Rev.1, MSC.1/Circ.1537/Rev.1 and MSC.1/Circ.1539/Rev.1.

Continuous ventilation of closed ro-ro and vehicle spaces should ideally always be available

regardless of weather conditions and that ventilation system openings should therefore be

considered unprotected downflooding points in stability evaluations.

However, for ships where it may not be technically feasible to treat some closed ro-ro and vehicle

space vent openings as unprotected openings, Administrations should be allowed to accept

alternative arrangements that provide an equivalent level of safety.

Accordingly, the pertinent unified interpretations in MSC.1/Circ.1535/Corr.1, MSC.1/Circ.1537

and MSC.1/Circ.1539 should be amended by inserting the phrases "closed ro-ro and vehicle

spaces" and "Where it is not technically feasible to treat some closed ro-ro and vehicle space

ventilators as unprotected openings, Administrations may allow an alternative arrangement that

provides an equivalent level of safety" where appropriate.

Draft amendments to the unified interpretation of paragraph 3.4.2 of part B of the 2008 IS Code

(MSC.1/Circ.1537)

SDC 6 agreed to the draft amendments to the unified interpretations of the 2008 Intact Stability

Code (MSC.1/Circ.1537), for submission to MSC 101 for approval with a view to dissemination as

MSC.1/Circ.1537/Rev.1.

MSC 96 approved the Unified interpretations of the 2008 IS Code (MSC.1/Circ.1537), including the

following unified interpretation of paragraph 3.4.2 of part B of the 2008 IS Code :

"For tankers assigned with a tropical load line, the ship should be assumed to be loaded

to its tropical load line."

IACS has noted some inconsistency in the understanding of how the aforementioned unified

interpretation should be followed by flag Administrations.

IACS members concluded that the following clarifications would assist in achieving consistency in

application of the unified interpretation of paragraph 3.4.2 of part B of the 2008 IS Code:

.1 the loading conditions should be with cargo homogeneously distributed throughout all

cargo tanks;

.2 a departure loading condition at the tropical load line and the corresponding arrival

loading condition should be considered; and

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.3 sea water density of 1.025 t/m3 should be assumed.

Doors in watertight bulkheads of cargo ships and passenger ships

IACS Unified Interpretation (UI) SC156 pertains to doors located in way of the internal watertight

subdivision boundaries and the external watertight boundaries that are necessary to ensure

compliance with the relevant subdivision and damage stability regulations. Subsequently, MSC 80

approved MSC/Circ.1176 on Interpretations of SOLAS chapters II-1 and XII, which included

provisions as per IACS UI SC156.

MSC/Circ.1176 was superseded by MSC.1/Circ.1464, which was approved at MSC 92. However,

the provisions related to doors in watertight bulkheads in MSC/Circ.1176 were kept unchanged in

MSC.1/Circ.1464.

IACS members agreed it would be appropriate to review IACS UI SC156.

During the development of Rev.1 of UI SC156, IACS noted that there appears to be some

inconsistencies between the requirements in the SOLAS and MARPOL Conventions and ICLL

regarding doors in watertight bulkheads.

These are:

.1 the requirements related to hinged watertight doors are only clearly specified in SOLAS;

and

.2 in SOLAS, the requirements for doors in watertight bulkheads vary according to the

frequency of use of the doors, i.e. "Norm Closed", "Perm Closed", "Norm Open", "Used",

etc. as shown in the table in the unified interpretation. However, the requirements in IMO

instruments other than SOLAS are compatible with those in SOLAS for doors in watertight

bulkheads to be used while at sea, which are described as "Used" in the table in the

unified interpretation; and there are no requirements for doors, other than "Used" doors,

in these other instruments.

SDC 6 agreed that, following IACS' recently updated Unified Interpretation (UI) SC156,

consequential amendments to MSC.1/Circ.1464/Rev.1 were necessary but that the concrete

actions to be taken would depend on the outcome of the SDS Working Group, which was

instructed to review SOLAS chapter II-1, parts B-2 to B-4, to ensure consistency with parts B and

B-1 with regard to watertight integrity, and any action to amend MSC.1/Circ.1464/Rev.1 would

follow from thereon.

The proposal to remove the inconsistencies for requirements for doors in watertight bulkheads

between SOLAS and other IMO instruments was supported in general, but would require

consideration by MSC as a new output proposal. Thus, Plenary invited Member States to liaise

with IACS and to submit a proposal for a new output to MSC 101.

Proposed amendments to MSC.1/Circ.1535, MSC.1/Circ.1537 and MSC.1/Circ.1539

USA proposed amendments to the unified interpretations in MSC.1/Circ.1535, MSC.1/Circ.1537

and MSC.1/Circ.1539 to include provisions on openings to ventilation systems for closed ro-ro and

vehicle spaces that must run continuously whenever vehicles are on board.

Safety risk related to openings to ventilation systems for closed ro-ro or vehicle spaces

19

The matter of concern relates to openings to ventilation systems that must provide continuous

ventilation to closed ro-ro or vehicle spaces and which might therefore be vulnerable to

downflooding in heavy weather or a damage casualty.

The recent unified interpretations regarding stability evaluation of potential downflooding points

only address openings to ventilation systems that must provide continuous air supply to engine-

rooms and emergency generator rooms, and do not include openings to ventilation systems for

closed ro-ro or vehicle spaces.

The proposed solution is to amend the relevant unified interpretations to include openings to

ventilation systems for closed ro-ro and vehicle spaces.

SOLAS and ICLL regulations pertaining to ventilation system openings

Regulation 19(4) of the International Convention on Load Lines, 1966 (ICLL) generally requires

ventilator openings to be fitted with weathertight closures unless they are of sufficient height that

closures can be safely omitted, as provided in regulation 19(3), i.e. at least 4.5 m above deck in

position 1 and 2.3 m above deck in position 2.

ICLL regulation 17(3) stipulates that ventilators necessary to continuously supply air to machinery

spaces and emergency generator rooms should meet the minimum heights of regulation 19(3).

Consequently, they would not need to be fitted with closures and can be left open regardless of

weather conditions.

SOLAS regulation II-1/7-2 provides the requirements for the calculation of the damage stability

survivability factor si. Factor si accounts for downflooding in the definition of angle Θv, which

includes the angle at which an opening incapable of being closed weathertight becomes

submerged.

SOLAS regulation II-1/35 requires category A machinery spaces, which include engine-rooms, to

have adequate air supply to operate the machinery at full power and also ensure the safety and

comfort of personnel in those spaces, even under heavy weather conditions.

SOLAS regulation II-2/20.3 pertains to the ventilation of closed ro-ro and vehicle spaces. On

passenger ships, it requires ventilation systems for those spaces to run continuously when

vehicles are in those spaces. On cargo ships, it requires ventilation systems for those spaces to run

continuously whenever vehicles are on board, unless impracticable, in which case the ventilation

system should be run daily as weather permits.

Unified interpretation MSC.1/Circ.1539

it may not always be possible to arrange sufficiently high ventilators to meet the ICLL requirement

for closures. In addition, even if a vent is fitted with a weathertight closure, the air supply to

engine-rooms and emergency generators cannot be closed off without potentially compromising

the ship's safety

Recognizing this situation, MSC 96 approved Unified interpretations of SOLAS chapter II-1

(MSC.1/Circ.1539), which include the following provision regarding the downflooding angle Θv in

SOLAS regulation II-1/7-2:

"3 In applying Θv, openings which cannot be or are incapable of being closed weathertight

include ventilators (complying with regulation 19(4) of the International Convention on

Load Lines, 1966) that for operational reasons have to remain open to supply air to the

engine room or emergency generator room

20

MSC 96 approved similar interpretations for the ICLL Protocol (MSC.1/Circ.1535/Corr.1) and the

2008 Intact Stability Code (MSC.1/Circ.1537).

These unified interpretations assume that the engine-room and emergency generator room air

supply vents will always be open, even if fitted with closures, and therefore require them to be

evaluated as potential downflooding points.

However, although SOLAS regulation II-2/20.3.1.2 also requires the continuous ventilation of

closed ro-ro and vehicle spaces when vehicles are on board, those ventilation system openings

are not included in the unified interpretations.

Amendments

Accordingly, annex to Unified interpretations relating to the Protocol of 1988 relating to the

International Convention on Load Lines, 1966 (MSC.1/Circ.1535/Corr.1), is to be amended as

follows:

Regulation 27(13)(e)

3 Unprotected openings include ventilators (complying with regulation 19(4) of

the International Convention on Load Lines, 1966) that for operational reasons

have to remain open to supply air to spaces the engine room, or emergency

generator room or closed ro-ro and vehicle spaces (if the same is considered

buoyant in the stability calculation or protecting openings leading below) for the

effective safe operation of the ship. Where it is not technically feasible to treat

some closed ro-ro and vehicle space these ventilators as unprotected openings,

Administrations may allow an alternative arrangement that provides an

equivalent level of safety.

The annex to Unified interpretations of the 2008 IS Code (MSC.1/Circ.1537) and SOLAS Chapter II-

1 (MSC.1/Circ.1539) will also require amendment in line with the above changes.

Unified interpretation of SOLAS regulations II-1/22-1 and II-2/21.4.13 regarding safe return to

port requirements for flooding detection systems

SDC 6 agreed with the draft MSC circular on Unified interpretation of SOLAS chapter II-2, for

submission to MSC 101 for approval.

At SDC 5, IACS sought clarification as to whether liquid level monitoring systems serving tanks

containing liquids, which are used as, or replace, flooding detection systems, should also meet the

safe return to port requirements in SOLAS regulation II-2/21.4.13.

SDC 5 agreed to the view of the majority of those that spoke that such systems should meet the

safe return to port requirements and invited IACS to develop a unified interpretation, taking into

account that there should be no retroactive application of the agreed understanding.

In considering the view expressed at SDC 5 that there should be no retroactive application, IACS

proposes that this unified interpretation should be applied to ships contracted for construction on

or after 1 July 2019, unless IACS members are provided with written instructions to apply a

different interpretation by the Administration on whose behalf they are authorized to act as a

recognized organization.

Paragraph 7 of the Guidelines for flooding detection systems on passenger ships

(MSC.1/Circ.1291) reads:

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"7 Any watertight spaces that are separately equipped with a liquid level

monitoring system (such as fresh water, ballast water, fuel, etc.), with an indicator

panel or other means of monitoring at the navigation bridge (and the safety

centre if located in a separate space from the navigation bridge), are excluded

from these requirements."

Interpretation

For passenger ships carrying 36 or more persons and subject to SOLAS regulation

II-1/8-1, the Safe Return To Port (SRTP) requirements of SOLAS regulation II-

2/21.4 apply to both:

.1 the flooding detection systems in the spaces as defined in paragraph 6

of MSC.1/Circ.1291; and

.2 the liquid level monitoring systems, which are used as, or replace, the

flooding detection systems, as specified in paragraph 7 of

MSC.1/Circ.1291.

Therefore, the exemption as given in paragraph 7 of MSC.1/Circ.1291 does not

apply in the context of SRTP.

IACS Unified Interpretation (UI) SC123 machinery installations – service tank arrangements -

Submitted by IACS

IACS members have discussed and reviewed typical fuel oil service tank arrangements for vessels

trading in Emission Control Areas (ECAs) that use both low sulphur distillate and residual grade

fuel oils. As a consequence, IACS has identified the need to revise its Unified Interpretation UI

SC123.

SOLAS regulation II-1/26.11 states:

"(…) Two fuel oil service tanks for each type of fuel used on board necessary for

propulsion and vital systems or equivalent arrangements shall be provided on each new

ship, with a capacity of at least 8 h at maximum continuous rating of the propulsion plant

and normal operating load at sea of the generator plant."

Recognizing the underlying SOLAS safety objective of maintaining an appropriate amount and

quality of fuel readily available for propulsion machinery and "vital systems", the existing

definitions of equivalency in IACS UI SC123 needed to be revised to recognize the use of low

sulphur fuels.

During the revision of IACS UI SC123, the following issues have been considered:

.1 typical fuel oil service tank arrangements for new and retrofitted vessels trading in ECAs

that use low sulphur and residual grade fuels oils;

.2 the potential hazards resulting from the emergency changeover of fuel oil of one grade

to another

SDC 6 agreed that this matter required further consideration and forwarded it to MSC 101 with a

request that it be considered under the Committee's new agenda item on "Development of

measures to enhance the safety of ships relating to the use of fuel oil".

22

* *

*

Correspondence groups established by SDC 6

Correspondence Group on Subdivision and Damage Stability (SDS)

Terms of reference :

• further develop draft amendments to the Revised Explanatory Notes to the SOLAS

chapter II-1 subdivision and damage stability regulations (resolution

MSC.429(98)),

• revise MSC.1/Circ.1572

Correspondence Group on Intact Stability

Terms of reference :

• further develop the draft interim guidelines with a view to finalization at SDC 7

• consolidate all three draft interim guidelines under a single set of guidelines

Correspondence Group on Industrial personnel

Terms of reference :

• further develop the draft new IP Code

Correspondence Group on Safety Measures for Non-SOLAS Ships Operating in Polar

Waters

Terms of reference :

• with a view to finalization at SDC 7, further develop the draft guidelines for safety

measures for fishing vessels of 24 metres and over operating in polar waters,

• further develop the draft guidelines for pleasure yachts of 300 GT and above not

engaged in trade operating in polar waters.

* *

*