Custody Transfer
Abbreviation: CT
Measurement and transfer of cargo from seller to buyer in a contractually-binding way, conducted by a third-party surveyor.
In practice
Joint surveyor + master + cargo officer perform tank-by-tank ullage, temperature, and density measurements before and after cargo operations. Discrepancies generate a Letter of Protest. Quantity differences are the main commercial dispute on every gas-carrier voyage.
Regulatory detail & full definition
On LNG, custody-transfer measurement uses tank-gauging (radar or float), trim/list correction, density (P,T-corrected), and shore vapour return for true mass. The CT certificate signed by the surveyor is the basis for invoicing — typical cargo USD 30-80M, so the integrity of the measurement matters. ISO 10976 governs LNG CTM; API MPMS Ch. 17 governs oil CTM.
Related
Source: ISO 10976:2015 (LNG); API MPMS Ch. 17 (petroleum)
High confidence
Editorial confidence: how we grade.