For ferry transport: a shipment number consists of 16 or 17 characters (depending on the ferry operator). The first 4 are letters identifying the ferry operator. The next 12 or 13 characters are the booking number, always ending with 001, 002 or a higher consecutive number. So, for example, in box 40 you enter: X-705 PONFHU12345678001
For container transport: A B/L number has a maximum of 17 characters, of which usually the first four letters stand for the SCAC code of the shipping company/shipbroker. So, for example, in box 40 you enter: X-705 ABCD0510098765431 ( X-705: the code of the previous arrangement).
By being extra alert to this in your supplementary declarations from now on, you will ensure that your cargo will always be able to proceed quickly after 1 October. Customs offers you these completion instructions (in Dutch) as support for the correct filing of further declarations. In addition, a separate information sheet is available that takes you through the customs chain step by step. Please consult these tools carefully. In this way, you will avoid making unnecessary errors.