Input dialog
- Last UpdatedDec 19, 2025
- 4 minute read
The input dialog consists of three tabs, "General" which is common for both calculations and then the tabs for selecting the tanks to include in the calculation, one for "Fuel Oil Tanks" and another for "Cargo Oil Tanks", use the tab appropriate for the calculations to be performed.
General Page
Figure 4:95. Oil Outflow - General Page
General data that applies to both sets of rules is given on this page of the dialog. Note that, if an item is associated with a check box, ticking this will cause the parameter to be calculated from the vessel's geometry.
|
Item |
Description |
|---|---|
|
Length, L |
96% of the total length on a waterline at 85% of the least moulded depth measured from the top of the keel, or the length from the foreside of the item to the axis of the rudder stock on that waterline, if that be greater. If the associated check box is ticked, then the program will calculate this value. |
|
AP to aft terminal of L |
Distance from the AP to the aft terminal of L (positive if terminals aft of the AP). This will also be calculated, if the length checkbox is ticked. |
|
Breadth mid, B |
Maximum moulded breadth of ship. |
|
Depth to upper deck, Ds |
Moulded depth measured at mid-length to the upper deck at side. |
|
Loadline draft, ds |
Vertical distance from the moulded base line at mid-length to the waterline corresponding to the summer freeboard draft to be assigned to the ship. |
|
Lightship draft, dls |
Moulded draft amidships corresponding to the lightweight. Note the partial draft, dp is Dls + 0.6(ds-dls) |
|
Max breadth at ds, Bs |
Greatest moulded breadth, at or below the deepest loadline draft, ds. If the associated checkbox is ticked, then the program will calculate this value. Note, however, that the program will assume the greatest value will be at the loadline draft. If this is not the case, then you should specify the value. |
|
Max breadth at 30% Ds, Bb |
Greatest moulded breadth, at or below the waterline (db) at 30% of the depth, Ds. If the associated checkbox is ticked, then the program will calculate this value. Note, however, that the program will assume the greatest value will be at the draft, db. If this is not the case, then you should specify the value. |
|
Tidal change |
Tidal change. Reductions in tide shall be expressed as negative values. For the purposes of this regulation, tc should be set to -2.5 m. |
|
Fuel oil density |
Nominal density of the oil fuel. This shall generally be taken as 1.000 kg/m3. If the density of the oil fuel is specifically restricted to a lesser value, the lesser value may be applied. |
Fuel Oil Tanks Page
Figure 4:96. Oil Outflow - Fuel Oil Tanks Page
The grid displays a list of compartments in the ship. The list can be filtered using the Category Filter. For example, selecting "FO Fuel Oil Tanks", will display only compartments assigned to this category.
All fuel oil tanks should be selected by checking the Select box. (Unchecked tanks specified as fuel oil tanks will have to be re-categorized, as the vessel does not comply, if they are used as fuel tanks.)
In the case of bottom damage, a certain amount of oil can be captured, if there is a non-oil tank below the cargo tank in question. If such a tank is present, then the Oil Capture? Box should be selected. This will result in a 40% reduction in outflow from bottom damage of the tank.
Cargo Oil Tanks Page
Figure 4:97. Oil Outflow - Cargo Oil Tanks Page
The grid displays a list of compartments in the ship. The list can be filtered using the Category Filter. For example, selecting "CGO Cargo Oil", will display only compartments assigned to this category.
All cargo oil tanks, should be selected by checking the Select box. In the case of bottom damage, a certain amount of oil can be captured, if there is a non-oil tank below the cargo tank in question. If such a tank is present, then the Oil Capture? Box should be selected. This will result in a 40% reduction in outflow from bottom damage of the tank.
The rules also specify a correction if an inert gas system is fitted. Note that for the correction to be applied, the gas pressure must exceed kPa. If the pressure specified is less than this, the tank is assumed to have no inert gas system. An inert gas system will result in a higher outflow.
The vessel's nominal deadweight (DWT), is used to determine the cargo oil density and should therefore be accurately given. Initially this is setup from the ship's main particulars, but, as it is not a requirement to specify the lightweight, the value obtained might not be accurate and should be checked. The DWT value is also used to determine whether the regulations are applicable. Tanker and combination carriers with a deadweight less than 5000 tonnes, are not considered.
A special rule for determining the limiting mean outflow parameter, OmLimit, for combination carriers, is given, which applies to vessels between 5000 and 200000 tonnes DWT. Check the "Combination Carrier?" Box, if the vessel falls within this category.
A correction factor, C3 = 0.77, is applied to the side damage outflow for ships having two longitudinal bulkheads inside the cargo tanks. Check the "2 or more longitudinal bulkheads in the cargo area?" box, if this applies.