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This is a Key Topic, with high value for all users.
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- On the Voyage Estimate menu, click Auto Calculate by Max Lift Qty. The following information is used:
- From the Vessel form:
- Capacity fields vary with Type Code, for example:
- Type Code T (Tanker): Capacity M3 or Capacity Bbl
- Type Code B (Bulk): Capacity (Bale) or Capacity (Grain)
- Vessel DWT (taking into account the season and the salinity of the berth)
- Constants and Safety Margins
- Capacity fields vary with Type Code, for example:
- Bunkers ROB
- Cargo Name
- Cargo Class Dry or Unspecified: Stowage Factor (M3/MT or Ft3/MT)
- Cargo Class Liquid: Density (API/Specific Gravity)
- Cargo Class Dry: The Capacity Basis default is Grain, but you can change it on the Cargo Name form.
- From the Vessel form:
- Quantities appear in Voyage Estimate Details view:
- On the Draft/Restrictions tab, in the Cargo and L/D Qty fields.
- In the Cargoes grid, in the CP Qty field, depending on configuration flags.
- You can override the calculated lift value.
To recalculate, clear the field and then press Enter. The new value appears blue.
To see the inputs to the calculation, on the Draft/Restrictions tab, hold your mouse pointer hover over the value in the Max Lift field.
Max Lift Calculation
In determining the Max Lift, three possibly restricting quantities are calculated:
- IMOS - Max Lift Calculations
- IMOS - Max Lift Calculations
- IMOS - Max Lift Calculations68714792
- 68714792
- 68714792
The Max Lift is taken as the most restrictive of these values.
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If the result from the Max Lift calculation is higher than the Max Available Deadweight, then the Max Lift is the Deadweight itself (the maximum the ship can lift).
Max Available Deadweight
Max Available Deadweight = Vessel Deadweight − Bunkers and Constants
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- Vessel DWT, SW Summer Draft, and TPC/TPI on the Vessel form.
- Information entered on the bottom half of the Vessel DWT/Draft tab.
If an exact baseline does not exist (meaning Deadweight, Draft, or TPC is missing) backups are used depending on the relevant loadline:
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Sea Constants, Fresh Water, Other Constants, and Bunker Margins come from the Vessel Consumption tab:
- In the In Port Consumption Table (Per Day) grid, the Margin column.
- Under Variables and Safety Margins, Constants Sea, Fresh Water, and Others fields.
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| Configuration Flags | |
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| Exclude Safety Margin from Max Lift Calc | When this flag is enabled, we do not include the Bunker Margins when calculating Bunkers and Constants. So, in our example, we would have 800 MT – 110 MT for Bunkers and Constants. The Max Available Deadweight would therefore equal 77,122.5 MT. |
| Enable Default Ending Rob Constants | When this flag is enabled, an Ending ROB Margin field appears on the Vessel Consumption tab. If we do not have initial bunker quantities, then we add on this constant. So, in our example, if we had no initial bunkers, and this constant had a value of 100 MT, Bunkers and Constants would be 800 MT + 100 MT = 900 MT. The Max Available Deadweight would therefore equal 76,912.5 MT. |
Other Notes
Unlike the IMOS - Max Lift Calculations 68714792 calculation, this portion of the Max Lift Calculation does not account for possible differences in salinity between the baseline used and the itinerary.
Max Deadweight Given Cubic Restrictions
For Gas Carriers and Tankers:
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- For LNG Vessels.
- If there are different cargo densities specified in the itinerary.
- If Capacity or Specific Gravity/Stowage Factor is missing.
Max Deadweight Given Draft Restrictions
This calculation happens in one of two ways, depending on whether we can determine the deadweight from the Deadweight Table in the DWT/Draft tab of the Vessel form.
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This calculation is only performed when we have a draft specified on an itinerary line.
Calculation Based on Deadweight Table
Notes
The Max Deadweight Given Draft Restrictions are not determined if:
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Following this calculation, the Bunkers and Constants (which are calculated as described in the IMOS - Max Lift Calculations 68714792 section) are subtracted to get:
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Max Deadweight Given Draft Restrictions = 64,616.3 MT - 200 MT = 64,416.3 MT
Calculation Based on TPC
If we fail to get a deadweight from the Deadweight Table calculation (for one of the reasons given under Notes in the relevant section), we calculate the max deadweight based on the vessel’s TPC. The equation for this method depends on whether the salinity on the itinerary line matches the baseline salinity we are using for our Max Lift Calculation (see the IMOS - Max Lift Calculations 68714792 -> Deadweight section for information on baselines).
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Consider the example we have from the IMOS - Max Lift Calculations section 68714792 section. Recall that our vessel has a TPC of 70 MT/CM and adjusted draft of 14.6875 M. Moreover, we have:
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Salinity Ratio = (1.025 kg/l - 1.000 kg/l) / (1.000 kg/l) = 0.025
Max Deadweight Given Draft Restrictions = (((14 M − 14.6875 M) * 70 MT/CM * 100 CM/M) + (77,812.5 MT) − (0.025 * 11,000 MT)) / (1 + 0.025) − 800 MT = 70,151.2 MT
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