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Locks and paddles.


Jerra
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I hope this is the correct part of the forum for the question!

 

The other day a gongoozler asked me a question which had never crossed my mind and so I couldn't provide an answer.

 

The question was "why does this lock have two ground paddles while the next one has a gate paddle and a ground paddle?"  I should add we were talking about the top gate.

 

So is there any rhyme or reason as to why this is so or was it just the whim of the original gate builder. 

 

 

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There is not a definitive answer, as paddle gear does depend, to some extent, on local circumstances. However, from the archive material I have seen, in general there were ground paddles for upper gates, and gate paddles for lower gates. Gate paddles were fitted to upper gates on some canals, possibly those which were more successful, after railway competition began, as a way of speeding up traffic. Ground paddles allowed locks to be built deeper than those with just gate paddles as they overcame the problem of water falling onto boats rising in the lock when only gate paddles were used. They were first used Jean de Locquenghien on the Willebroeck Canal which opened in 1561. The first ground paddles in the UK were on the Newry Canal. and were built by Thomas Steers, who had served in William of Orange's army in the Low Countries in the 1690s, where he could have seen those on the Willebroeck Canal. By increasing the depth of locks, they would have probably reduced the cost of construction, making the building of canals more economic, and thus a major factor in the success of English canal development.

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Were you on the T&M, Meaford perhaps? 

Locks were generally built to the same style locally, so adjacent locks would be similar, but a rebuild or a realignment would mean that adjacent locks may differ.

 

I ask if it is Meaford as the top lock of the four is significantly older than the other three, the canal having been relaligned 20-30 years after it was built. Early T&M narrow locks on the eastern side tend to have on ground and one gate paddle (it isn't clear whether the gate paddle is an original feature) whereas later locks had two ground paddles. The change in convention had occured by the time the canal at Meaford was realigned. 

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This is a Macclesfield Canal drawing which shows the upper ground paddle feeding into the centre of the forebay, with the lower gate recesses being cut away where the gate paddles would fit against the chamber wall.

Macclesfield Canal.jpg

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1 hour ago, magpie patrick said:

Were you on the T&M, Meaford perhaps? 

Locks were generally built to the same style locally, so adjacent locks would be similar, but a rebuild or a realignment would mean that adjacent locks may differ.

 

I ask if it is Meaford as the top lock of the four is significantly older than the other three, the canal having been relaligned 20-30 years after it was built. Early T&M narrow locks on the eastern side tend to have on ground and one gate paddle (it isn't clear whether the gate paddle is an original feature) whereas later locks had two ground paddles. The change in convention had occured by the time the canal at Meaford was realigned. 

It was the T&M but I honestly can't remember which locks.  Sorry.

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At Meaford the 3 locks replaced a staircase pair which is buried in the undergrowth on the offside. At Etruria, Lawton and Middlewich, staircase locks were replaced by standard locks also. With Etruria and Meaford the prospect of railway competition may have influence the change, and such impetus seems to have been a factor for doubling the Cheshire Locks

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Many thanks to all for the information.   Does anybody know why all locks aren't to the one design.   By that I mean at some places all top gates seem to have gate paddles and at others all ground paddles.   I understand the changes owing to things like doing away with a staircase but what about as a general principle, does one type have an advantage over the other for example.

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You should try the Bedford Ouse, where:

 

4 locks have mitre gates top and bottom (Roxton, Barford, Willington, Castle Mill - all built relatively recently) 

8 locks have mitre gates at the bottom and a guillotine at the top (Hemingford, Houghton, Godmanchester, Brampton, Offord, Eaton Socon, Cardington, Bedford) 

2 locks have a guillotine at the bottom and mitre gates at the top (St Ives, St Neots)

1 lock has a guillotine at each end (Brownshill)

 

All the mitre gates have a slacker (paddle) each (except Castle Mill, below, which has a rather unusual slacker arrangement).

 

It certainly keeps you on your toes.... 

dsc_0825.jpg

Edited by Scholar Gypsy
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2 hours ago, Jerra said:

Many thanks to all for the information.   Does anybody know why all locks aren't to the one design.   By that I mean at some places all top gates seem to have gate paddles and at others all ground paddles.   I understand the changes owing to things like doing away with a staircase but what about as a general principle, does one type have an advantage over the other for example.

 

I think, in good old boating tradition, they just used whatever was lying around at the time..

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On 20/09/2021 at 11:52, Jerra said:

The question was "why does this lock have two ground paddles while the next one has a gate paddle and a ground paddle?"  I should add we were talking about the top gate.

 

So is there any rhyme or reason as to why this is so or was it just the whim of the original gate builder. 

 

 

 

I'd say that ground paddles had very little to do with the gate carpenter.  They really have to be built when the lock is!

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1 hour ago, TheBiscuits said:

 

 

I'd say that ground paddles had very little to do with the gate carpenter.  They really have to be built when the lock is!

Obviously.  By gate builder i was really meaning the person who said x locks at these y locations and made to this design.

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5 hours ago, Scholar Gypsy said:

You should try the Bedford Ouse, where:

 

4 locks have mitre gates top and bottom (Roxton, Barford, Willington, Castle Mill - all built relatively recently) 

8 locks have mitre gates at the bottom and a guillotine at the top (Hemingford, Houghton, Godmanchester, Brampton, Offord, Eaton Socon, Cardington, Bedford) 

2 locks have a guillotine at the bottom and mitre gates at the top (St Ives, St Neots)

1 lock has a guillotine at each end (Brownshill)

 

All the mitre gates have a slacker (paddle) each (except Castle Mill, below, which has a rather unusual slacker arrangement).

 

It certainly keeps you on your toes.... 

dsc_0825.jpg

 

And that's before we get to quirks like flights of steps instead of ladders built into the Little Paxton lock, or the historic lock they just abandoned and let the river channel upstream of it run shallower.

 

Or the locks (Roxton is one below) with gates designed with thick iron reinforcement beams protruding several inches from the gate on the inside of the lock to snag the fenders and bows of boats pulled forward by the water flow when you open the paddles. Take it whoever designed those just didn't like boats much

(Great Ouse paddles take a lot of unwinding when you realise you can't just drag your boat back away from the gate too. Don't ask me how I know!)

image.png.d0cca83bc2f63a249524fb92a942edd1.png

 

 

 

 

The Castle Mill lock you pictured is actually the best designed of the lot considering the extra height must have been needed for flood defence. Fills from the middle at the bottom on both sides which doesn't move your boat much and the slackers/paddles are right next to your centre line. No guillotines with 6 min 30 second timers there either!

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20 hours ago, enigmatic said:

 

And that's before we get to quirks like flights of steps instead of ladders built into the Little Paxton lock, or the historic lock they just abandoned and let the river channel upstream of it run shallower.

 

Or the locks (Roxton is one below) with gates designed with thick iron reinforcement beams protruding several inches from the gate on the inside of the lock to snag the fenders and bows of boats pulled forward by the water flow when you open the paddles. Take it whoever designed those just didn't like boats much

(Great Ouse paddles take a lot of unwinding when you realise you can't just drag your boat back away from the gate too. Don't ask me how I know!)

image.png.d0cca83bc2f63a249524fb92a942edd1.png

 

 

 

 

The Castle Mill lock you pictured is actually the best designed of the lot considering the extra height must have been needed for flood defence. Fills from the middle at the bottom on both sides which doesn't move your boat much and the slackers/paddles are right next to your centre line. No guillotines with 6 min 30 second timers there either!

 

Yes, that's why I use bow and stern lines when going up, even when single handed. 

 

I think Castle Mill must depend on the design & size of the boat. With mine the flow pulls the boat sideways into the middle of the lock. OK if you are on your own, but not very pleasant if you are sharing with something plastic....  You are right the floods can be quite something, and indeed can submerge the lock completely!

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