Q. What are the different ways of securing grain or reducing the volumetric heeling moments? The various ways are:
- Installing longitudinal division.
- Overstowing a compatible cargo.
- Securing with wire mesh.
Q. How should the longitudinal divisions be installed?
In the filled compartments, trimmed; the filled compartments, untrimmed; and partly filled compartments, longitudinal divisions may be installed as a device to reduce the adverse heeling moments due grain shift provided that:
- the division is grain tight;
- construction complies with the strength requirements given in regulations 11, 12 and 13;
- In tween deck the division extends from deck to deck and in other compartments it extends downwards from underside of deck or hatch cover as specified in part B of code.
Q. What is saucer in context of Grain? What does saucer do? How is it created?
Saucer can be made in way of a hatch opening to reduce the healing moment, instead of a longitudinal division, in case of a filled trimmed compartment. This however, cannot be done in the case of linseed and other seed having similar properties. The depth of the saucer measured from the bottom of the saucer to the deck line shall be as follows
- For ships with a moulded breadth of upto 9.1m not less than 1.2m
- For ships with a moulded breadth of 18.3m or more not less than 1.8m
- For ships with a moulded breadth between 9.1m and 18.3m the minimum depth of the saucer shall be calculated by interpolation.
The top of the saucer shall be formed by the underdeck structure in way of the hatchway i.e. hatch side girders or coming and hatch end beams. The saucer and hatchweay above shall be completely filled with bagged grain or other suitable cargo laid down on a separation cloth or its equivalent and stowed tightly against adjacent structure so as to have a bearing contact with such structure to a depth equal to or greater than one half of the depth of saucer. If the hull structure to provide such bearing surface is not available. The saucer shall be fixed in position by steel wire rope, chain or double steel strapping and spaced not more than 2.4m apart..
Q. What is Bundling in grain? How is it accomplished?
As an alternative to filling the saucer in a filled trimmed compartment with bagged grain or other suitable cargo a bundle of bulk grain may be used provided that:
The dimensions and means for securing the bundle in place are the same as specified for a saucer.
The saucer is lined with a material acceptable to the administration having a tensile strength of not less than 2,687N per 5cm strip and which is provided with suitable means for securing at top.
As an alternative to above a material acceptable to the Administration having a tensile strength of not less than 1.344N per 5cm strip may be used if the saucer is constructed as follows:
- Athwartship lashing acceptable to the administration shall be placed inside the saucer formed in the bulk grain at intervals of not more than 2.4m. These lashings shall be of sufficient length to permit being drawn up tight and secured as the top of the saucer.
- Dunnage not less than 25mm in thickness or other suitable material of equal strength and between 150mm and 300mm in width shall be placed fore and aft over these lashings to prevent the cutting or chafing of the material which shall be placed thereon to line the saucer.
The saucer shall be filled with bulk grain and secured at the top and further dunnage shall be laid on top after lapping the material before the saucer is secured by settings up the lashings. If more than one sheet of material is used to line the saucer they shall be joined at the bottom either by sewing or by a double lap. The top of the saucer shall be coincidental with the bottom of the beams when these are in place and suitable general cargo or bulk grain may be placed between the beams on top of the saucers.
Q. What preparation must be done on grain surface prior overstowing with bagged grain or other compatible cargo?
Where bagged grain or other suitable cargo is utilized for the purpose of securing “partly filled” compartments the free grain surface shall be level and shall be covered with a separation cloth or equivalent or by a suitable platform. Such platform shall consist of bearer spaced not more than 1.2m apart and 25mm boards laid thereon spaced not more than 100mm apart. Platforms may be constructed of other materials provided they are deemed by the Administration to be equivalent.
The platform or separation cloth shall be topped off with bagged grain tightly stowed and extending to a height of not less than one sixteenth of the maximum breadth of the free grain surface or 1.2m whichever is the greater. The bagged grain shall be carried in sound bags which shall be well filled and securely closed.
Instead of bagged grain, other suitable cargo tightly stowed and exerting at least the same pressure as bagged grain as above may be used.
Q. How do you do the strapping of grain surface?
When in order to eliminate heeling moments in partly filled compartments, strapping or lashing is utilized, the securing shall be accomplished as follows:
The grain is trimmed and leveled to the extent that it is very slightly crowned and covered with burlap separation cloths, tarpaulins or the equivalent. The separation cloths and / or tarpaulins shall overlap by at least 1.8m.
Two solid floors of rough 25mm by 150mm to 300mm lumber shall be laid with the top floor running longitudinally and nailed to an athwartships bottom floor. Alternatively, one solid floor of 50mm lumber, running longitudinally and nailed over the top of a 50mm bottom bearer not less than 150mm wide, may be used. The bottom bearer shall extend the full breadth of the compartment and shall be spaced not more than 2.4m apart. Arrangement utilizing other materials and deemed by the administration to be equivalent to the foregoing may be accepted.
Steel wire rope (19mm diameter or equivalent) double steel strapping (50mm × 1.3mm and having a breaking load of at least 49kN), or chain of equivalent, each of which shall be set tightly by means of a 32mm turnbuckle, may be used for lashings. A winch tightner used in conjunction with a locking arm may be substituted for the 32mm turnbuckle when steel strapping is used provided, suitable wrenches are available for setting up as necessary. When steel strapping is used, not less than three crimps seals shall be used for securing the ends. When wire is used not less than four clips shall be used for forming eyes in the lashings. Prior to the completion of loading the lashing shall be positively attached to the framing at a point approximately 450mm below the anticipated final grain surface by means of wither a 25mm shackle or beam clamp of equivalent strength.
The lashing shall be spaced not more than 2.4m apart and each shall be supported by a bearer nailed over the top of the fore and aft floor. This bearer shall consist of lumber of not less than 25mm by 150mm or its equivalent and shall extend the full breadth of the compartment. During the voyage the strapping shall be regularly inspected and set up where necessary.
Q. How is the grain surface secured with wire mesh?
When in order to eliminate grain heeling moments in “partly filled” compartments, strapping or lashing is utilized the securing may as an alternative to the method described in A17, be accomplished as follows:
The grain shall be trimmed and leveled to the extent that it is very slightly crowned along the fore and aft centerline of the compartment. The entire surface of the grain shall be covered with burlap separation cloths, tarpaulins, or the equivalent. The covering material shall have a tensile strength of not less than 1.344N per 5cm strip.
Two layers of wire reinforcement mesh shall be laid on top of the burlap or other covering. The bottom layer is to be laid athwartships and the top layer is to be laid longitudinally. The lengths of wire mesh are to be overlapped at least 75mm. The top layer of mesh is to be positioned over the bottom layer in such a manner that the squares formed by the alternate layers measure approximately 75mm by 75mm. The wire reinforcement mesh is the type used in reinforced concrete construction. It is fabricated of 3mm diameter steel wire having a breaking strength of not less than 52kN/cm2, welded in 150mm × 150mm square. Wire mesh having mill scale may be used but mesh having loose flaking rust may not be used.
The boundaries of the wire mesh at the port and starboard side of the compartment shall be retained by wood planks 150mm × 50mm.
Q. How is the wire mesh and the planks maintained in position?
This is accomplished by the hold down lashings. The hold down lashings, running from side to side across the compartment. These shall be spaced not more than 2.4m apart except that the first and the last lashing shall not be more than 300mm from the forward or after bulk head, respectively. Prior to the completion of the loading each lashing shall be positively attached to the framing at the point approximately 450mm below the anticipated final grain surface by means of either a 25mm or beam clamp of equivalent strength. The lashing shall be led from this point over the top of the boundary plank, which has the function of distributing the downwards pressure exerted by the lashing. Two layers of 150mm × 25mm plank shall be laid athwartships centered beneath each lashing and extending the full breadth of the compartment.
The hold down lashing shall consists of steel wire rope (9mm diameter or equivalent), double steel strapping (50mm × 1.3mm and having a breaking load of at least 49kN), or chain of equivalent strength, each of which shall be set tight by means of a 32mm turnbuckle. A winch tightener, used in conjunction with a locking arm, may be substituted wrenches are available for setting up as necessary. When steel strapping is used, not less than three crimps seals shall be used for securing the ends. When wire rope is used, not less than four clips shall be used for forming eyes in the lashings. During the voyage the hold down lashings shall be regularly inspected and set up where necessary.
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