Victoria’s secrets

2 responses to “Victoria’s secrets”

1. Redmond O'Brien | Sunday 21 January 2018 at 13:26 |

   Hi BJG,
   Excellent photos. A great opportunity to see the workings of a canal lock.
   Presumably the openings inside the gate locks (on the walls) also let in water?
   Why is one end of the lock much shallower than the other end?
   Redmond.

2. bjg | Sunday 21 January 2018 at 14:20 |

   Some of the apertures were for the chains used to open and close the gates before hydraulics were applied; you can see the old winch mechanisms on the banks.

   A lock is essentially a step. With the lock full, the upper gates are opened and a boat enters; it needs a certain depth of water over the upper sill. That depth is maintained outside the lock by Meelick weir and inside the lock by the lower gates.

   The boat moves forward into the lock chamber, clear of the sill, and the water is let out. The boat descends, but it needs to end up lower than when it started, with the requisite depth of water over the lower sill and the water level with the river below the weir (the level maintained in this case by Parteen Villa Weir).

   bjg

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