RAINWAT is the "Regional Arrangement Concerning the Radiotelephone Service on Inland Waterways". It is an agreement to implement common principles and rules for the safe carriage of people and goods on Inland Waterways. The signatory countries are: Austria, Belgium, Bulgaria, Croatia, the Czech Republic, France, Germany, Hungary, Luxembourg, Moldova, Montenegro, the Netherlands, Poland, Romania, Serbia, the Slovak Republic and Switzerland.
Where a VHF is required on the inland waterways of the signatory countries, this must be capable of Automatic Transmitter Identification System (ATIS) transmissions, and have the feature activated. An ATIS number is required which is issued by Ofcom when you add one or more pieces of ATIS equipment to your Ship Radio Licence.
A copy of the Regional Arrangement should be carried on board. This can be downloaded from the RAINWAT website.
Ofcom has provided a comprehensive explanation of ATIS and RAINWAT on their website, which explains what ATIS is, how it works and the action you need to take prior to venturing onto the inland waterways of the signatory countries.
It is important to note that ATIS may not be used within 14 nautical miles of the low waterline around the coast of the UK, the Isle of Man and the Channel Islands.
The use of DSC (VHF Ch. 70) is in most countries restricted to coastal waters and DSC transmissions should not be made when navigating the inland waterways.
Not all VHF sets are capable of ATIS transmissions; you may need to contact your manufacturer for advice.