Draft survey calculator: cargo from drafts
Calculate the cargo quantity from the drafts before and after loading or discharge, using the UNECE method. All intermediate values are shown.
ExampleThis is the result of the example values entered.
Intermediate values
| Step | Initial | Final |
|---|---|---|
| Tf (m) | 4.200 | 11.000 |
| Tm (m) | 5.600 | 11.300 |
| Ta (m) | 7.000 | 11.600 |
| Apparent trim (m) | 2.800 | 0.600 |
| Tfp (m) | 4.151 | 10.990 |
| Tap (m) | 7.081 | 11.617 |
| True trim (m) | 2.930 | 0.628 |
| Quarter mean (m) | 5.604 | 11.301 |
| First trim correction (MT) | 111.105 | 17.972 |
| Second trim correction (MT) | 31.006 | 1.533 |
| D after trim (MT) | 21,592.111 | 46,819.505 |
| Density correction (MT) | -84.262 | -182.710 |
| D after density (MT) | 21,507.849 | 46,636.795 |
| Deductibles (MT) | 9,305.000 | 1,104.000 |
| Net displacement (MT) | 12,202.849 | 45,532.795 |
Change a value to email the result of your own calculation.
How we calculate this
Would you like to know how we calculate this and how it is handled in FOSS? We would be glad to talk it through.
Related template
Draft survey form
Frequently asked questions
What is a draft survey?
A draft survey determines the weight of the cargo by comparing the ship's displacement before and after loading or discharge, based on the drafts read at the hull.
Where do I get displacement, TPC, LCF and MTC?
From the ship's hydrostatic tables or trim and stability book. Read them at the quarter mean the tool shows, and interpolate where needed.
What if the cargo comes out negative?
Then something is probably wrong: check that you chose loading or discharge as intended and that the initial and final drafts are not swapped.
What does the draft survey tool not include?
Not included: the correction for marks that are not at midships, and the keel plate correction. Use the tool as a check next to the surveyor's report, not as a replacement.