| Name | Type | Cardinality | Description |
| Vessel | Vessel | [1, 1] | Vessel asset subject to Classification. |
| ClassCatalogue | ocx:ClassCatalogue_T | [1, 1] | The Class catalogues provided as part of the OCX. The catalogue can hold the society’s definitions of cross-sections, materials, hole shapes etc. |
| ProcessLayer | ocx:ProcessLayer_T | [0, 1] | Abstract element which can hold any process related business information. (To be designed). |
| UnitsML | unitsml:UnitsMLType | [1, 1] | Container for UnitsML units, quantities, and prefixes. |
| Equipments | ocx:Equipments_T | [0, 1] | Container for equipments. |
| Header | ocx:Header_T | [1, 1] | The header information of an XML export. |