Circular Letter
MSC/Circ.1108
GUIDELINES FOR ASSESSING THE LONGITUDINAL STRENGTH OF BULK CARRIERS DURING
LOADING, UNLOADING AND BALLAST WATER EXCHANGE
(25 May 2004)
1. The Maritime Safety Committee, at its
seventy-sixth session (2 to 13 December 2002), having considered the results of
various FSA studies on bulk carrier safety, agreed that the risk control option
calling for the provision of detailed, comprehensive and user-friendly
information covering stability and strength characteristics of the ship s hull
during loading and unloading should be applied to new bulk carriers. Furthermore, MSC 76 noted that the
above-mentioned risk control option was more relevant for smaller ships with
respect to stability and for larger ships with respect to structural strength,
and instructed the Sub-Committee on Stability and Load Lines and on Fishing
Vessels Safety (SLF) and the Sub-Committee on Ship Design and Equipment (DE) to
develop relevant guidelines.
2. The DE Sub-Committee, at its forty-seventh
session (25 February to 5 March 2004), noting that the SLF Sub-Committee, at
its forty-sixth session (8 to 12 September 2003), had prepared draft SOLAS
amendments to address the stability issues on bulk carriers of less than 150 m
in length, agreed that for bulk carriers of 150 m in length and above,
user-friendly guidelines for assessing the longitudinal strength would be more
appropriate.
3. The Maritime Safety Committee, at its
seventy-eighth session (12 to 21 May 2004), following the recommendation of DE
47, approved the Guidelines for assessing the longitudinal strength of bulk
carriers during loading, unloading and ballast water exchange, set out in the
annex.
4. Member Governments are invited to bring the
annexed Guidelines to the attention of loading instrument manufacturers,
related computer software developers, mariners, dry cargo terminal operators
and other parties involved in loading, unloading and ballast water exchange
operations.
ANNEX.
GUIDELINES FOR ASSESSING THE LONGITUDINAL STRENGTH OF BULK CARRIERS DURING
LOADING, UNLOADING AND BALLAST WATER EXCHANGE
The
aim of these Guidelines is to ensure the provision of detailed, comprehensive
and user-friendly information covering the longitudinal strength
characteristics of the ship s hull during loading, unloading and ballast water
exchange.
The
loading manual is a document which describes:
.1 the loading conditions on which the design of
the ship has been based, including permissible limits of still water bending
moments and shear forces;
.2 the results of the calculations of still
water bending moments, shear forces and, where applicable, limitations due to
torsional loads;
.3 envelope results and permissible limits of
still water bending moments and shear forces in the hold flooded condition as
applicable;
.4 the cargo hold(s) or combination of cargo
holds that might be empty at full draught.
If no cargo hold is allowed to be empty at full draught, this should be
clearly stated in the loading manual; and
.5 the allowable local loads for the structure
(e.g. hatch covers, decks, double bottom, tank top).
2.2.1
A loading instrument is an instrument, either analogue or digital, by means of
which it can be easily and quickly ascertained that, at specified read-out
points, the still water bending moments, shear forces, loads on the double
bottom and the still water torsional moments, where applicable, in any loading
or ballast condition will not exceed the specified permissible values during
planned loading, unloading and ballast water exchange.
2.2.2
In this context the loading instrument comprises the hardware and software.
3.1.1
For the loading, unloading and stowage of solid bulk cargoes, reference should
be made to SOLAS regulation VI/7 and the related Code of Practice for the Safe
Loading and Unloading of Bulk Carriers (BLU Code).
3.1.2
The loading manual should contain typical loading sequences from commencement
of cargo loading to reaching full deadweight capacity for homogeneous
conditions, relevant part load conditions and alternate hold loading conditions
where applicable. Typical unloading
sequences for these conditions should be included.
3.1.3
The typical loading sequences should be developed paying due attention to the
loading rate, the deballasting capacity and the applicable strength and draught
limitations.
3.1.4
The typical loading and unloading sequences should include, as relevant:
.1 alternate light and heavy cargo loading
condition;
.2 homogeneous light and heavy cargo loading
condition;
.3 short voyage condition where the ship is
loaded to maximum draught with limited bunkers;
.4 multiple port loading/unloading condition;
.5 deck cargo condition, where permitted;
.6 block loading; and
.7 ballast water exchange conditions, if not
covered by other documents.
3.2.1
The input/output format of the loading instrument should, as far as
practicable, be easily comparable in information and format to the loading
manual so that the operators will easily gain