Working through Magpie Patrick's belongings has revealed the following. It looks "too high quality" to be a throwaway in a magazine (which is what its location first suggested). Any thoughts?

Not sure if I'm missing something but it says at the bottom it was free with Waterways World in October 1998.

15 minutes ago, IanM said:

Not sure if I'm missing something but it says at the bottom it was free with Waterways World in October 1998.

Good spot - I missed that!

It is not clear to me how the lock is emptied. It appears that the side culverts are used in both filling and emptying.

12 minutes ago, Mike Todd said:

It is not clear to me how the lock is emptied. It appears that the side culverts are used in both filling and emptying.

Are these Perry Barr locks?

As you probably know these locks fill from the top and bottom of the locks keeping boats ascending in quite a nice position. Garrison is similar. Perhaps that’s it?

26 minutes ago, Mike Todd said:

It is not clear to me how the lock is emptied. It appears that the side culverts are used in both filling and emptying.

Yes. Both top and bottom (ground) paddles are connected to the same culvert which has connections to the lock chamber at either end and in the middle, so much smoother water flow in the chamber when filling and emptying.

And if the culvert is working properly the bottom gates will close on opening the top paddles.

22 minutes ago, Rob-M said:

And if the culvert is working properly the bottom gates will close on opening the top paddles.

I'd always heard that, and that BW had blocked the lowest connection to prevent it happening, to avoid unwitting pedestrians being struck by a balance beam moving with nobody near it, but the drawing shows that the culvert connection is not directly behind open bottom gates.

I'm sure there are a couple of Perry Barr locks where the bottom gates will close when the top paddles are raised and you see a lot of water disturbance behind the gates when the lock is filling.

1 hour ago, Rob-M said:

I'm sure there are a couple of Perry Barr locks where the bottom gates will close when the top paddles are raised and you see a lot of water disturbance behind the gates when the lock is filling.

Yes there is, 10pm when we went through last time it was hard to remember which ones ( or indeed if I was seeing things…)

I’m pretty sure there’s a video by Cruising the cut showing it. @ditchcrawler will probably know which ones.

Found a picture I took but unsure which one..

By coincidence we are currently moored in the middle of the Perry Barr flight, I was initially confused when filling them to see water entering the lock from next to the bottom gates!

31 minutes ago, Tim Lewis said:

By coincidence we are currently moored in the middle of the Perry Barr flight, I was initially confused when filling them to see water entering the lock from next to the bottom gates!

I was the same first time I went up them and thought there was an issue by the bottom gates causing the water disturbance.

One of Andy Tidy's Canal Hunter YouTube videos shows him demonstrating that at least some of the Perry Bar locks will close the bottom gates when you draw the top paddles. I think it's the "Carrying Coal from Cannock" series.

That's a rather nice diagram, I hadn't considered that the ground paddles would be at opposite ends of the same culvert but why wouldn't they be if the culvert extends the full length of the lock, and with the multiple links between the culvert and lock chamber it'll smooth the flow in both directions although obviously far more noticeable when filling.

There's at least one lock on the Thames which has multiple side entry points for the culvert. Can't recall which one, but the lockies warned us before filling as it catches you out if you don't expect it. A full length narrowboat gets quite a shove. Think it's in the Windsor area.

1 hour ago, Ken X said:

There's at least one lock on the Thames which has multiple side entry points for the culvert. Can't recall which one, but the lockies warned us before filling as it catches you out if you don't expect it. A full length narrowboat gets quite a shove. Think it's in the Windsor area.

Romney lock in Windsor is definitely a side-filler. I don’t think it’s the only one on the Thames though.

I seem to remember The Severn and / or larger Trent locks filling all the way along. It’s quite a pull on the lines/ chain if you loose concentration and drift out a bit?

The widened GU locks have 3 entries into the lock chamber each side. They also seem to start filling at different times working from upstream to downstream but that might just be due to the flow of water rather than any design feature.

3 hours ago, phantom_iv said:

Romney lock in Windsor is definitely a side-filler. I don’t think it’s the only one on the Thames though.

Hambledon is another..🙂

As is Castle Mill on the Great Ouse.

42 minutes ago, IanM said:

The widened GU locks have 3 entries into the lock chamber each side. They also seem to start filling at different times working from upstream to downstream but that might just be due to the flow of water rather than any design feature.

That’s right except I think Knowle are different- after traversing all the GU locks it came as a surprise to find our boat behaving differently up Knowle. Someone explained why but I’ve temporarily forgotten..

Knowle have sidepond paddles on the offside.

2 hours ago, Stroudwater1 said:

I seem to remember The Severn and / or larger Trent locks filling all the way along. It’s quite a pull on the lines/ chain if you loose concentration and drift out a bit?

I tend to find the keepers on the Severn seem to only use the paddles on the one side to fill and hold the boat to the lock wall.

4 hours ago, Stroudwater1 said:

That’s right except I think Knowle are different- after traversing all the GU locks it came as a surprise to find our boat behaving differently up Knowle. Someone explained why but I’ve temporarily forgotten..

IIRC

It's just the size of the paddles they are much larger than Hatton. Hence the swirling in the pounds between locks.

13 minutes ago, GUMPY said:

IIRC

It's just the size of the paddles they are much larger than Hatton. Hence the swirling in the pounds between locks.

From memory the Knowle top and bottom paddles are labelled as 3 ft square, I think the rest of the GU Ham Baker gear are 2 ft 6 in square.

10 minutes ago, David Mack said:

From memory the Knowle top and bottom paddles are labelled as 3 ft square, I think the rest of the GU Ham Baker gear are 2 ft 6 in square.

That's just under 3sqft extra🤔

On 30/09/2026 at 16:18, 1st ade said:

Working through Magpie Patrick's belongings has revealed the following. It looks "too high quality" to be a throwaway in a magazine (which is what its location first suggested). Any thoughts?

On 30/09/2026 at 18:46, Mike Todd said:

It is not clear to me how the lock is emptied. It appears that the side culverts are used in both filling and emptying.

A lovely Edward Paget-Tomlinson rendition.