Anyhow Weir Lock

[ditchcrawler]

1 hour ago, Tony Brooks said:

I am sure I have had my 54ft plus  a longer one in Aynho lock.

If there are 2 sub 70 foot boats they can get in with one at an angle touching the bottom gate and one touching the top. probably about 58 60 footers

[magpie patrick]

8 hours ago, NB Alnwick said:

We will probably never know why this lock was designed this way but I have never bought in to the traditional theory. Similarly I don't buy in to the notion that best practice is to lock one boat at a time - we have often had three boats in the that lock which makes it is a lot more manageable when boating single handed . . .

 I'm pondering whether these locks were a bit of an afterthought - the river levels probably weren't as well managed when the canal was built and it may have been that single gates in the style of a flood gate or stop gate were planned, only to realise that it would spend most of the time closed and blocking the navigation. At least one lock on the Boyne Navigation (Stackallen Guard) was a replacement for a flood gate which spent 5-6 months of the year closed to navigation. Whilst Stackallen GUard lock is a conventional chamber three other locks on the Boyne are clay sided and lozenge shape and may also have been provided retrospectively. 

[magpie patrick]

9 hours ago, Tracy D'arth said:

And why pairs of gates top and bottom on the whole Bosley flight?

 These are (almost) the last survivors of a format that was relatively common - The Ashton Canal and the Shropshire Union (B&LJ) both had double top gates at one time - I think the double gates at Fairfield survive on the Ashton as do the ones on the narrow locks at Ellesmere Port

On busy canals they proved a blimmin' nuisance and were got rid of