Thanks to Padhraic Conneally, who left a Comment that started the hunt, and to Zara Brady (IWAI Corrib), who visited the site to ask about something else entirely, and finally to Trevor Northage of AnglingCharts.com, who provided the name and other information, we now have two extra Galway waterways to add to the list. They’re both covered, with maps, on this page, although only the larger, the Ballycuirke Canal, gets its name in the heading.
I would welcome more information about both canals. It seems that the Ballycuirke was built for drainage but also used for transport; I would be glad to know more about such transport.
Irish waterways history 
PS I am also currently offering lots about Irish Tripboats so on ebay http://www.ebay.co.uk/itm/Lough-Erne-Trip-Boat-out-National-Trust-Crom-Molaise-Kestrel-Inishcruiser-c2009-/270896096451?pt=UK_Collectables_Bus_CoachCollectables_SM&hash=item3f12aa64c3 and on Specialist Corrib http://www.specialistauctions.com/auctionsearch.php?posted=1&keywords=corrib&category=0
I think the unmnaed cruiser in Athlone might be Perfect Dawn. used to belong to Sean O’Reilly, Edenderry before he joined the heavy metal brigade.
Thanks, Princess. Now I have to work out how to move this to the relevant page! bjg