[Default] On Wed, 16 May 2007 10:54:16 +0100, [EMAIL PROTECTED] finished tucking into their plate of fish, chips and mushy peas. Wiping their mouth, they swiggged the last of their cup of tea, paid the bill and wrote::
>But it does tend to support my belief that the Rochdale locks originally (ie >in the case of the ones on the trans-Pennine length, until the 1990s) lacked >conventional bywashes, instead relying on the system involving slots in the >upper gate recess walls. These allow water to overflow into the chamber via >the upper ground paddle culverts (possibly supplemented by water coming over >the top gates when there is too much for the slots - which are relatively >short compared to conventional bywash weirs - to cope with), and bottom gates >which are (or should be) designed with the tops of the gates at exactly the >same level as these slots, so that if the lock is full the water will overflow >over the bottom gates. The same system was used elsewhere (GU, K&A, >Basingstoke that I know of) and does seem to have been favoured by Jessop. > I'm fairly certain the locks on the Cromford didn't have bywashes and it would be our intention not to install them when we restore - we'd use the method used on the Erewash, where the bottom gates are slightly shorter than the top ones, so water can flow through the lock when the level in the upper pound is high. Brian L Dominic Web Sites: Canals: http://www.brianscanalpages.co.uk Friends of the Cromford Canal: http://www.cromfordcanal.org.uk (Waterways World Site of the Month, November 2005)
