A draft-survey on a barge is usually called gauging.

As for sea-going vessels, inland shipping barges also have tables for displacement and made according an international agreement, the "Convention relative au jaugeage des bateaux de navigation intérieure" (february 15, 1966 Geneva). Countries that have signed the convention have also reported likewise to the UN.
In The Netherlands the "Binnenschepenwet" is based upon this convention, with its "Metingsbesluit Binnenvaartuigen 1978" being the executive part (Binnenvaart Meetbrief (from wikipedia, dutch)).

Unlike sea-going displacement/deadweight tables, tables for inland shipping barges have a complete different lay-out.
Basically there are 2 types:

1. 'draft' starting at 0. This 0 reflects the empty barge loadline (see pdf opens in new window)
2. 'draft' starting at a number which reflects the empty barge's draft (see pdf opens in new window)

On the hull reference marks are placed, measuring 30cm long x 4cm high, usually painted white. The barge's owner is responsible for the maintenance of these marks. If he fails to do so, the 'meetbrief' is considered void

The procedure is as follows:

• measure at all reference point the distance from the underside of the mark to the waterline
• calculate the average of these measurements
• deduct the average from the maximum from the table
• interpolate (or extrapolate) the corresponding deadweight in m3
• check water-density
• repeat the whole process after the vessel finished loading or discharging
• if the water-density has changed, you need to apply a correction on the first found average (item 33-b in the 'meetbrief')
• take the difference between initial and final measurement/deadweight and multiply this with the actual water-density
• apply any corrections for other loaded or discharged weights, such as intaken bunkers, fres water etc.

These calculations and results are only valid if the vessel was not aground, was floating freely and no other weight-manipulations were done such as ballast.