From OpenStreetMap Wiki
For the height (the difference of water level from the top and the bottom basins), height, lock:height, lock_height and maxheight are used. height is more often used and simple :-)
- CEMT key
- Classification of European Inland Waterways on wikipedia.
Caution : in the english page, there is more classification RA, RB, RC, RD and one VIc "3×2 convoy"
- phone, contact:phone, lock:phone, waterway:lock:phone ?
- vhf, VHF, lock:VHF_channel, waterway:vhf_channel, vhf_channel, VHF_channel, VHF-channel, lock:channel, contact:vhf ?
- website, url ?
I suggest :
- vhf_channel (like OpenSeaMap harbors)