Draft Surveys
Accurate cargo quantity through precise displacement calculation
A draft survey determines the weight of cargo loaded or discharged by measuring the change in a vessel's displacement. Performed correctly, it is one of the most reliable methods of quantity determination for bulk cargoes, and the figure that settles bills of lading, freight and trade contracts.
Vetko's surveyors apply the UN ECE / industry-recognised methodology, accounting for water density, ballast, bunkers, constants and trim corrections, to deliver a defensible weight that protects both shipper and receiver.
Scope of work
What this survey covers.
- Initial draft survey
- Interim draft survey
- Final draft survey
- Cargo quantity certification
What you receive
Clear, evidential deliverables.
- Full draft survey report with all readings and corrections
- Density, ballast and bunker measurements
- Calculated cargo quantity statement
- Certificate of quantity for commercial use
The draft surveys process
- WP-01
Initial survey (light ship)
Drafts, ballast, bunkers and constants are recorded before operations.
- WP-02
Sounding & density checks
Tank soundings and dock/sea water density are measured to correct displacement.
- WP-03
Final survey (loaded)
Readings are repeated on completion to establish the displacement difference.
- WP-04
Certification
The corrected cargo quantity is calculated and certified for the parties.
Who commissions this
- Ship owners
- Charterers
- Commodity traders
- Cargo owners
- Stevedores
Frequently asked
How accurate is a draft survey?+
Under good conditions a competently executed draft survey is typically accurate to within ±0.5%, making it suitable for trade settlement of bulk commodities.
Can you survey at anchorage?+
Yes, subject to weather and sea state. Conditions affecting accuracy are always noted in the report.
Related services
All servicesCommission a draft surveys survey
Tell us the vessel, cargo and port. Vetko Surveys will mobilise and report, promptly and independently.