On Fri, 19 Jun 2009 16:00:54 +0100, "Mack, David" <[email protected]> wrote:
>See also http://en.wikipedia.org/wiki/File:Ribble_Link_04c216.jpg which >has another unhelpful photograph, but does explain how it works. >It's a rising sector gate. The gate drops to the bed to allow boats to >pass, which is why the TNC site and various boating blogs all show a >rather nondescript narrows with boats approaching / passing through / >departing, but no gate. For example see >http://nbfreespirit.blogspot.com/2008/07/going-through-sea-lock.html. Thanks for those, David: that's very helpful. The photos are indeed unhelpful but the descriptions are useful. It seems that the entry in the Wikipedia article on canal locks is misleading: it mentions the Ribble lock but its description covers only sector gates with vertical axes. I have amended the text under Variations/Steel gates/Rotating-sector gates on http://en.wikipedia.org/wiki/Lock_(water_transport) Perhaps some learned readers might be able to check and improve my amendment. The page would benefit from several other amendments, but vita brevis .... I was asking about sector locks because I wanted to put up a page on my site about them and I was going to refer to British examples. Apart from the Ribble, Limehouse is the only one I can think of, but perhaps there are lots of them elsewhere. I've put up my page at http://irishwaterwayshistory.com/about/irish-waterways-operations/a-sector-lock-kilrush-marina/ The sector lock leads into Kilrush marina on the Shannon estuary. Sector gates are also being installed as flood defences at Spencer Dock, where the Royal Canal meets the River Liffey in Dublin. Interestingly, the Kilrush lock and the associated embankment solved problems that were identified by Commander William Mudge RN, Admiralty surveyor, in 1831: he was one of the three members of the Commission for the Improvement of the Navigation of the Shannon, and at that time the Shannon estuary steamers had to use Cappagh pier, outside Kilrush, because at low tide Kilrush had only a small creek running through it. Nowadays, inland waterways boats going to sea often head for Kilrush, which is also one of the bases from which dolphin-watching trips are provided. There is a resident school of bottlenose dolphins in the estuary. bjg
