(I made WaterwayMap.org)
> What's interesting and somewhat amusing is that this map has determined that the section of the Soar that joins with the Trent just north of Loughborough is apparently unnavigable
The boat views only use the OpenStreetMap `boat` tag. If a section of river is missing from WWM.org, then it's likely the tag is missing from the OSM waterway. You can fix that!