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Max Lift is the maximum quantity a vessel can lift in the port in the voyage that has the most restrictive deadweight and draft limits. This amount can be calculated based on the density of the cargo, the vessel's deadweight, and the weight of bunkers and everything on the vessel.

1. On an Estimate column or details toolbar, click Image Modified or Image Modified and then 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

   • 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.

2. Quantities appear in Estimate details:

   • 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.

3. You can override the calculated lift value. 

4.  
   To recalculate, clear the field and then press Enter. The new value

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1. appears blue.
   

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To see the inputs to the calculation, on the Draft/Restrictions tab, hover over the value in the Max Lift field.

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In determining the Max Lift, three possibly restricting quantities are calculated:

• Max Available Deadweight

• Max Deadweight Given Cubic Restrictions

• Max Deadweight Given Draft Restrictions

The Max Lift is taken as the most restrictive of these values.

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Max Lift = Capacity divided by Stowage Factor

Max Available DeadweightMax Available Deadweight = DWT minus Bunkers ROB on Arrival minus Constants and Margins

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The deadweight comes from the baseline chosen for calculations:

• Vessel DWT, SW Summer Draft, and TPC/TPI on the Vessel form.

• Information entered on 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:

• Tropical Fresh Water -> Tropical Salt Water -> Summer Salt Water

• Winter Fresh Water -> Winter Salt Water -> Summer Salt Water
  Note: Winter Fresh Water is not an available line, so a backup is always used.

• Summer Fresh Water -> Summer Salt Water

When Summer Salt Water is used as a backup for Winter/Tropical loadlines, the draft and the deadweight are adjusted as follows:

• Tropical SW Draft = Summer SW Draft + 1/48 * Summer SW Draft
  
  Tropical SW DWT = Summer SW DWT + (Tropical SW Draft − Summer SW Draft) * TPC *100 CM/M
  
  

• Winter SW Draft = Summer SW Draft − 1Draft − 1/48 * Summer SW Draft
  
  Winter SW DWT = Summer SW DWT − DWT − (Summer SW Draft − Winter Draft − Winter SW Draft) * TPC * 100 CM/M

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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.

ROB Bunkers and Bunkers Received come from the Voyage/Estimate.

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Adjusted Vessel DWT = 80,000 MT − (15M − 14MT − (15M − 14.6875 M) * 70 MT / CM * 100CM / M = 77,812.5 MT

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Max Available Deadweight = 77,812.5 MT − 800 MT − 800 MT = 77,012.5 MT

Other Notes

Unlike the Max Deadweight Given Draft Restrictions calculation, this portion of the Max Lift Calculation does not account for possible differences in salinity between the baseline used and the itinerary.

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This calculation is not performed:

• 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

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The Max Deadweight Given Draft Restrictions are not determined if:

• There are less than two lines in the Deadweight Table.

• Every draft in the Deadweight Table is greater than the itinerary’s ESWD.

Calculation

First, the draft in the itinerary is converted into the Equivalent Salt Water Draft, as follows:

Equivalent Salt Water Draft (ESWD) = Itinerary Draft * (1 − 1 − 0.92 (1.025 kg/l − Itinerary l − Itinerary Salinity))

In this equation, 1.025 is the density of salt water.

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If not, we order the lines by draft and find the closest line with a draft greater than the ESWD (call it LG), and the closest line with a draft less than the ESWD (call it LL). We then extrapolate the deadweight through a linear equation as follows (recall that the equation of a line is y = mx + b):

m (slope) = (LG.Deadweight − LLDeadweight − LL.Deadweight) / (LG.Draft − LLDraft − LL.Draft)
b (intercept) = LL.Deadweight − m Deadweight − m * LL.Draft
Table Deadweight = m * ESWD + b

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Following this calculation, the Bunkers and Constants (which are calculated as described in the Max Available Deadweight section) are subtracted to get:

Max Deadweight Given Draft Restrictions = Table Deadweight − Bunkers Deadweight − Bunkers and Constants

Special Case: ESWD is Greater than Every Draft in the Table

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ESWD = 13 M * (1 − 0.92 (1.025 kg/l − 1.l − 1.000 kg/l)) = 12.701 M

Then looking through the table, since we do not have a row with a draft within .005 of 12.701, we take the row with draft 13M as LG, and the row with draft 12M as LL. From these two points we extrapolate the Max Deadweight Given Draft Restrictions as follows:

m = (66,500 MT − 60MT − 60,200 MT) / (13 M − 12 M − 12 M) = 6,300 MT/M

b = 60,200MT − 6200MT − 6,300 MT/M * 12 M = −15 −15,400 MT

Table Deadweight = 6,300 MT/M * 12.701M - 15,400MT = 64,616.3MT

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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 Max Available Deadweight -> Deadweight section for information on baselines).

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Max Deadweight Given Draft Restrictions = Max Available Deadweight − Deadweight − (Adj Vessel Draft − Itinerary Draft − Itinerary Draft) * (TPC * 100 CM/M)

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Consider the example we have from the Max Available Deadweight 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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Max Deadweight Given Draft Restrictions = 77,012.5 MT − MT − (14.6875 M − 14M − 14.0 M) * (70 MT/CM * 100 CM/M) = 72,200 MT

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Salinity Ratio = (Baseline Salinity − Itinerary Salinity − Itinerary Salinity) / (Itinerary Salinity)

Max Deadweight Given Draft Restrictions = (((Itin Draft − Adj Draft − Adj Vsl Draft) * TPC * 100 CM/M) + (Adj Vsl DWT) −  − (Salinity Ratio * Lightship)) / (1 + Salinity Ratio) − Bunkers  − Bunkers and Constants

Example

Consider the example we have from the Max Available Deadweight section. Instead of going to a port with a Winter Salt loadline, suppose we go to a port with a Winter Fresh loadline. Let’s say this port has a draft of 14M. Our vessel would still have a TPC of 70MT/CM, an adjusted draft of 14.6875M, an adjusted deadweight of 77,812.5MT, and 800MT worth of Bunkers and Constants (See Max Available Deadweight for how these values are obtained). Moreover, let’s say that our vessel has a Lightship value of 11,000MT. Lightship is specified in the Details tab of the vessel form.

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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 − 14M − 14.6875 M) * 70 MT/CM * 100 CM/M) + (77,812.5 MT) −  − (0.025 * 11,000 MT)) / (1 + 0.025) − 800  − 800 MT = 70,151.2 MT

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