Classifying recreational waterways by navigable draught

There is much concern in many parts of Europe, and especially on the secondary waterways in France, about maintenance of canal banks and the related issue of dredging. As author of the European Waterways Map & Directory, I adopted for that overview map the classification proposed by PIANC in 1999. This was later endorsed as UNECE Resolution No. 52, at the initiative of several organisations, including the European Boating Association. This classification focuses on boat size overall, i.e.
RC – motor yachts 15m long, 4m beam, 3.75m air draught and 1.50 m draught
RB Рcabin cruisers and small yachts  9.50m long, 3m beam, 2.50m air draught and 1m draught
(RD is for standing mast routes, while RA is for light craft such as rafts and inflatables.)

Because of the sensitivity of dredging, I have adopted a different approach to categorising waterways in the new Imray map we have just completed. I know Inland Waterways of France¬†is misleading by giving the ‘official’ draught, and one member of sister organisation DBA The Barge Association wrote to me about cruising on the Canal de la Robine as being closer to agriculture than navigation!

We are now proposing the following legend for this new French map.

So the thickest line corresponds to high-capacity waterways, generally offering a draught of at least 2 m. Then comes the commercial Class I or ‘Freycinet’ waterways, offering 1.80m in principle. The third category is recreational waterways offering a draught in the range of 1.40-1.60m, while a thin line without dark edges corresponds to waterways where the design draught is 1.00-1.30m.
And we place the clear caveat: Caution: these dimensions (headroom and draught) may not always be available. I believe we cannot be too literal in plotting all the anomalies throughout the network, that’s not the job of a simple overview planning map.