General
2.1 The pattern of grain surface movement relates to a transverse section across the portion of
the compartment being considered and the resultant heeling moment should be multiplied by the
length to obtain the total moment for that portion.
2.2 The assumed transverse heeling moment due to grain shifting is a consequence of final
changes of shape and position of voids after grain has moved from the high side to the low side.
2.3 The resulting grain surface after shifting shall be assumed to be at 15° to the horizontal.
2.4 In calculating the maximum void area that can be formed against a longitudinal structural
member, the effects of any horizontal surfaces, e.g. flanges or face bars, shall be ignored.
2.5 The total areas of the initial and final voids shall be equal.
2.6 Longitudinal structural members which are grain-tight may be considered effective over
their full depth except where they are provided as a device to reduce the adverse effect of grain
shift, in which case the provisions of A 10.9 shall apply.
2.7 A discontinuous longitudinal division may be considered effective over its full length.
Assumptions
In the following paragraphs it is assumed that the total heeling moment for a compartment is
obtained by adding the results of separate consideration of the following portions:
2.8 Before and abaft hatchways:
1. If a compartment has two or more main hatchways through which loading may take
place, the depth of the underdeck void for the portion or portions between such
hatchways shall be determined using the fore and aft distance to the midpoint between
the hatchways.
2. After the assumed shift of grain the final void pattern shall be as shown in figure B
2-1.
![](/PUC/Handlers/ToonAfbeelding.ashx?pucid=PUC_2405_14&versienummer=1&bestand=1000015620.jpg)
(1) If the maximum void area which can be formed against the girder at B is less than the initial
area of the void under AB, i.e. AB × Vd, the excess area shall be assumed to transfer to the final
void on the high side.
(2) If, for example, the longitudinal division at C is one which has been provided in accordance
with A 10.9, it shall extend to at least 0.6 m below D or E whichever gives the greater depth.
2.9 In and abreast of hatchways
After the assumed shift of grain the final void pattern shall be as shown in figure B 2-2 or figure B
2-3.
1. Without longitudinal division:
![](/PUC/Handlers/ToonAfbeelding.ashx?pucid=PUC_2405_14&versienummer=1&bestand=1000015621.jpg)
(1) AB Any area in excess of that which can be formed against the girder at B shall transfer to
the final void area in the hatchway.
(2) CD Any area in excess of that which can be formed against the girder at E shall transfer to
the final void area on the high side.
2. With longitudinal division:
![](/PUC/Handlers/ToonAfbeelding.ashx?pucid=PUC_2405_14&versienummer=1&bestand=1000015622.jpg)
(1) The excess void area from AB shall transfer to the low side half of the hatchway in which
two separate final void areas will be formed, viz. one against the centreline division and the other
against the hatch side coaming and girder on the high side.
(2) If a bagged saucer or bulk bundle is formed in a hatchway it shall be assumed for the
purpose of calculating the transverse heeling moment that such a device is at least equivalent to the
centreline division.
(3) If the centreline division is one which has been provided in accordance with A 10.9, it shall
extend to at least 0.6 m below H or J whichever gives the greater depth.
Compartments loaded in combination
The following paragraphs describe the pattern of void behaviour which shall be assumed when
compartments are loaded in combination:
2.10 Without effective centreline divisions:
1. Under the upper deck - as for the single deck arrangement described in B 2.8.2 and B
2.9.1.
2. Under the second deck - the area of void available for transfer from the low side, i.e.
original void area less area against the hatch side girder, shall be assumed to transfer
as follows: one half to the upper deck hatchway and one quarter each to the high side
under the upper and second deck.
3. Under the third and lower decks - the void areas available for transfer from the low
side of each of these decks shall be assumed to transfer in equal quantities to all the
voids under the decks on the high side and the void in the upper deck hatchway.
2.11 With effective centreline divisions which extend into the upper deck hatchway:
1. At all deck levels abreast of the division the void areas available for transfer from the
low side shall be assumed to transfer to the void under the low side half of the upper
deck hatchway.
2. At the deck level immediately below the bottom of the division the void area available
for transfer from the low side shall be assumed to transfer as follows: one half to the
void under the low side half of the upper deck hatchway and the remainder in equal
quantities to the voids under the decks on the high side.
3. At deck levels lower than those described in B 2.11.1 or B 2.11.2, the void area
available for transfer from the low side of each of those decks shall be assumed to
transfer in equal quantities to the voids in each of the two halves of the upper deck
hatchway on each side of the division and the voids under the decks on the high side.
2.12 With effective centreline divisions which do not extend into the upper deck hatchway:
Since no horizontal transfer of voids may be assumed to take place at the same deck level as the
division, the void area available for transfer from the low side at this level shall be assumed to
transfer above the division to voids on the high side in accordance with the principles of B 2.10 and
B 2.11.