An increasing number of harbours in the Netherlands are now using the aanuit app to allow you to pay for overnight moorings, water and electricity.
This is particularly useful for smaller yacht clubs or municipal harbours where they are not manned but is also used by some of the larger harbours such as the Entropot in Amsterdam. Given the difficulty of using UK bank or credit cards in the Netherlands I can imagine this is going to make life easier for regular UK visitors to the Dutch waterways as it will allow them to access these services with one account already set up.
You can register online but need your IBAN (International Bank Account Number) for your UK bank account. This can normally be found on your bank statement which is often accessible via your online banking app.
Each mooring has different services which it can charge for in slightly different ways. For instance some charge for metered electricity (typically 50c/kwh). Or after selecting your location you may be asked whether you want harbour dues met stroom (with power) or zonder stroom (without). In some cases registration is required to gain access to shore facilities and the app will send you a message with a code to get into the showers.
Billing is done at the end of the month, and although there is an option to pay via credit card without an account this incurs an additional charge of €1/transaction and only limited services are available.