What would you say is the shallowest lock on the UK Inland Waterways ?

Question

Hi Boaties,

Having travelled most of the system over the last 20-odd years, and consulted good old Nicholsons books, and other sources, I cannot find one shallower than one not far from my home boatyard, at Stony Stratford.

It has a rise / fall of 13 inches.

I find the fine little thing on the east of the little town amusing.

It is naturally very slow to empty or fill, due to the small pressure differential. I have been through many a 6ft lock in a similar time.

Question is > why such a small lock ?

Some say it is simply due to a very slight gradient in the landscape, some say it is due to a minor micalculation between fellow canal-builders from opposite directions, others say it was onced used as a just a toll point.

Any notions ?

Bob

Answer 1

Hawkesbury lock is only 2 to 3inches deep at the most.

Historically when canals were built,canal company's  safe guarded thier water so they built what is called a Stop Lock and that is what they built near Bedworth another very shallow one.

Answer 2

I think the Graham Palmer lock on the Monty is 7 inches.

If its on a continous land gradient they will have to build a lock sooner or later - so they compromise between earthworks and lock depth.

Also, there are a few stop locks between canals at junctions thaty are often zero inches - bottom of the shroppie for example. This is often open both ends.

Some were used to establish the right to close water off between canal companies. These tend to be at junctions.

On non-contour canals they are used to overcome small drops, thats all - the cost of the lock was less than the contour detour or earthworks.

I don't thionk locks were put in specifically for tolls - the cost and time lost would not be acceptaable to the canal buidler nad operator respectively.

I think tolls where narrowing brick embankments with swing bars over them - the narrowing of the cut can still be seen but the "gates" are all gone.

Before long all tolls were paid at transhipment warfs.

Stoney lock probably needs a bit of work on leaks.