GUIDANCE TO SHIPS' CREWS AND
TERMINAL PERSONNEL FOR BULK CARRIER INSPECTIONS
(Adopted
on 27 November 1997)
THE ASSEMBLY,
RECALLING
Article 15(j) of the Convention on the International Maritime Organization
concerning the functions of the Assembly in relation to regulations and
guidelines concerning maritime safety,
RECALLING
FURTHER that resolution A.797(19) urges shipowners, ship operators, shipmasters
and terminal operators to take immediate measures as specified in the annex thereto,
including measures for shipowners to implement a planned maintenance scheme and
to conduct "owners' surveys" of cargo holds before loading and after
unloading and maintain on board a log of these surveys, and that terminal
personnel are aware of areas of specific concern relating to loading and
unloading,
RECALLING
ALSO that resolution A.744(18) requires the shipowner to maintain on board
documentation relating to inspection carried out by ship's personnel with
respect to structural deterioration and the condition of the coating, if any,
BEING
CONCERNED at structural damages inflicted on ships carrying solid bulk cargoes
which are one of the causes of the considerable number of bulk carrier losses,
sometimes without trace, and the heavy loss of life incurred,
HAVING
CONSIDERED the recommendation made by the Maritime Safety Committee at its
sixty-sixth session,
1.
ADOPTS the Guidance to Ships' Crew and Terminal Personnel for Bulk Carrier
Inspections, set out in the annex to the present resolution;
2.
INVITES Governments to bring the Guidance to the attention of shipowners, ship
operators and shipmasters of ships entitled to fly their flag as well as to
terminal personnel concerned, and to urge them to implement it as appropriate;
3.
REQUESTS the Maritime Safety Committee to keep the Guidance under review and
amend or extend it, as necessary.
GUIDANCE TO SHIPS' CREWS AND
TERMINAL PERSONNEL FOR BULK CARRIER INSPECTIONS
1.1
This document is intended to provide guidance to ship's crew and terminal
personnel with respect to the principal areas on bulk carriers that are likely
to be susceptible to corrosion or damage.
1.2
Under the Guidance, it is considered the responsibility of the owner to
maintain and, where necessary, report on deficient conditions found, together
with any repair(s) carried out. This document is intended to provide guidance
to personnel not experienced in conducting inspections. To facilitate effective
discharge of this responsibility and recognizing the normal duties of ships'
crew and terminal operators, it has been thought desirable to provide them with
a simple guide that explains the areas of principal concern.
1.3
In this connection, it should be understood that the ship's crew and terminal
operators may not be qualified in the inspection of ships. It should also be
recognized that such inspections cannot in any way replace surveys conducted by
flag States or recognized organizations acting on their behalf.
1.4
This document is also considered as an appropriate basis for assisting in the
implementation of an effective programme to maintain the ship in a satisfactory
condition between the required periodical surveys.
2.1
Responsibility for performing periodical inspection of the hull structure of
bulk carriers in accordance with the Enhanced Survey Programme (ESP) rests with
the flag Administration or recognized organization.
2.2
It is important to recognize, however, that severe structural damage may occur
to bulk carriers due to loading/unloading operations. Such damage may occur
instantly, and may, in severe cases, endanger the ship's safety unless
rectified rapidly. Furthermore, minor cracks, which have been undetectable at a
given ESP survey, may develop into serious defects prior to the next ESP
survey.
2.3
In view of this, it is recommended that terminal operators and members of the
ship's crew themselves regularly inspect the cargo holds, hatch covers and
ballast tanks with a view to detecting damage and defects. ESP documentation
should be used as guidance on specific parts of the structure needing
particular attention in individual ships.
2.4
From a safety point of view it is desirable that inspections of cargo holds by
the ship's crew or terminal operators are conducted before all loading and
after all unloading operations, although practical limitations will have to be
taken into account.
2.5
To maximize the effect of such inspections by ship's crew or terminal
personnel, an appropriate log of such inspections should be kept on board. For
inspections performed by the ship's crew, it is recommended that the form
"Owner's Inspection Report" incorporated in resolution A.744(18) on
ESP be used for this purpose, and made available for surveyors from the flag
Administration or recognized organization. This report will also assist the
shipowner in developing the survey programme, in co-operation with the flag
Administration or recognized organization, which is required by SOLAS.
3.1
A bulk carrier is a cargo ship designed and built for carriage of dry bulk
cargoes such as grain, coal, ore, etc. The cargo hold structure with topside
tanks at both shoulders and double bottoms with hoppers at both wings has been
designed as the best structure for dry bulk cargo transportation. The shape of
topside tanks provides sufficient stability to prevent dangerous cargo shift,
and bilge hoppers contribute to convenience in collecting the cargoes on
discharge.
3.2
In addition to light bulk cargoes, coal and ore are the main cargoes carried.
Coal and light bulk cargoes are stowed in every cargo hold. Iron ore, however,
is usually shipped in alternate cargo holds because of its high specific
gravity. This is done for the purpose of avoiding excessively stiff ship motion
and also for the convenience of loading facilities.
3.3
On designing a bulk carrier, loading patterns and sequences reflecting the
specific gravities of intended cargoes and ballasting patterns in various
operation modes are taken into consideration. These design considerations are described
in loading and operation manuals which provide ship officers with basic loading
patterns, strength features and limitations of the ship.
4. DEFINITIONS AND
TERMINOLOGY
4.1
Bulk carrier: a bulk carrier is a cargo ship intended for carriage of dry bulk
cargoes such as grain, coal, ore, etc., provided with topside tanks at both
shoulders and bilge hoppers in both double-bottom wings in the cargo space.
Below is a typical midship section and general arrangement.
Figure
1
Typical
midship section and general arrangement
4.2
Topside tank: tanks provided in cargo spaces at both shoulders, as the space
(1) shown in the drawing above.
4.3
Bilge hopper: a conventional bulk carrier has hopper structures at both bottom
wings in cargo holds. This part of the cargo hold is called the "bilge
hopper". Double-bottom tanks in way of bilge hopper are often called
"bilge hopper tanks". In the diagram, the space is shown as (2).
4.4
Girder and floor in double bottom: provided in double-bottom tanks,
"girder" usually indicates a strong frame, usually with the full
depth, provided in ship's longitudinal direction. The girder fitted on the
centreline is called "centre girder", while the others are called
"side girders". "Floor" means strong framing in ship's
transverse direction provided in double bottom. In double bottom beneath cargo
holds, floor plates are usually solid ones with full depth of the tank. In this
regard, solid ones are called "solid floors" as distinct from the
others.
4.5
Transverse web in topside tanks: strong framing provided in topside tanks in
the transverse direction also called "transverse ring". Of a
transverse ring in a topside tank, the part supporting the upper deck is called
"deck transverse", the part attached to the side shell is called
"side transverse" and the part attached to the bottom is called
"(topside) bottom transverse".
4.6
Transverse web in bilge hopper tanks: strong framing provided in the transverse
direction in a bilge hopper tank. Transverse webs are called "bilge hopper
transverse", "side transverse" and "bottom transverse"
in accordance with the name of the hull members to which they are attached.
4.7
Framing of various kinds: on a typical bulk carrier, framing is designed as a
longitudinal system in topside and double-bottom tanks and as a transverse
system at cargo hold side shell. Framing fitted in ship's longitudinal
direction are called "longitudinals". To identify them in detail, the
name of the plate they are attached to is added, such as "deck longitudinals",
"side longitudinals", "bottom longitudinals", etc. Framing
attached to the side shell in the cargo holds are called "hold
frames", "side frames", "main frames", "shell
frames", etc.
Figure
2
Typical
cross-section of cargo ship (bulk carrier)
5. GROUPING OF BULK CARRIERS ACCORDING TO
DIMENSIONS
5.1
In general, bulk carriers are grouped into three categories according to size.
These are: capesize, panamax, and other smaller types. Among the smaller types,
ships of 30,000 to 45,000 dwt having five cargo holds are called "handy
bulkers". Panamax bulkers are bulk carriers having a breadth of 32.2 m,
and are the largest ships able to transit the Panama Canal. Ships of this kind
usually have seven cargo holds and a deadweight of around 50,000 to 60,000
tonnes. Bulkers with dimensions greater than the panamax ships are called
"capesize bulkers". Capesize bulkers have nine or more cargo holds
and a deadweight in excess of 100,000 tonnes.
5.2
Capesize and panamax bulk carriers are generally engaged in carriage of raw
materials for industrial plants, such as coal and iron ore. Smaller bulk
carriers and some panamax ones are generally engaged in the trade of grain.
Lumber and industrial products are generally shipped by handy size or smaller
bulkers.
Figure
3
Various
bulk carriers
5.3
In the trade of food resources such as wheat, corn, and lumber, unloading ports
usually have no cargo-handling facilities and the bulk carriers employed are
often equipped with their own cargo gear, while panamax or capesize bulk carriers
are gearless.
6. STRUCTURAL FEATURES AND TYPICAL DAMAGE
6.1.1
The longitudinally continuous upper deck of a bulk carrier suffers hull girder
stress. The longitudinal bending causes an axial force on the upper deck that
may cause cracking of the deck plate at the locations where the stress is
concentrated.
6.1.2
Bulk carriers have cargo hatchways for the convenience of cargo-handling
facilities. These hatchways reduce the ship's torsional strength and invite
concentrated stress at the hatchway corners which may be evident by cracking of
the deck plates in these areas.
6.1.3
Cross-deck strips come under stress by transverse bending. The transverse
bulkheads provide transverse strength to a bulk carrier and the cross-deck
strips provide the strength to withstand the resultant axial forces in a
transverse direction.
Figure
4
Check
points on the upper deck
Buckling
of cross-deck strips
6.1.4
Generally, longitudinal beams are arranged under the longitudinally continuous
upper deck outboard of the side lines of the cargo hatchways. This is called
the longitudinal system. When the deck beams for cross-deck strips are also
arranged in this manner, buckling of the cross-deck strips may take place due
to insufficient strength against the axial forces acting on them in a
transverse direction. The transverse system is the preferred method of
construction for cross-deck members. Particular attention should be given to
buckling of the main deck on those ships where the cross-deck strips are
arranged in the longitudinal system.
Figure
5
Comparison
of stiffening systems for cross deck
Cracking
6.1.5
There are various types of cracking in the upper deck. Those propagating from
the cargo hatchways are generally considered serious to the ship's safety:
.1 Hatchway corners
The large cargo hatchway openings reduce the
torsional strength of the hull and invite stress concentration at their corners
on the upper deck. In this regard, upper deck plating at hatchway corners is one
of the focal points for cracking. Particular attention should be paid to these
areas during inspection.
Figure
6
Cracking
at hatchway
.2 Upper deck plating at deck fittings
Various metal fittings are welded to the
upper deck plating. These installations may cause stress concentrations at the
welded joints or have defects in the welds. Deck platings in the vicinity of
manholes, hatchside coaming end brackets, bulwark stays, crane post foundations
and deck houses, etc. are to be carefully watched for cracking.
Figure
7
Various cracking in upper deck plating