Can someone explain the Regent's roving bridge to a simpleton?

[Battle Cruiser]

Hi all,

 

Please be kind to me for asking something probably so simple, but I am unsure as to the operation / usage of the roving bridge over the Regent's canal at Hampstead Road lock, which has come about due to me being sure it wasn't used to allow horses to cross without unhitching. It's the towing of boats coming upstream that's puzzling me.

 

 

 

I've tried slowly re-reading this many times but it's only making a small amount of sense!

https://www.locallocalhistory.co.uk/ctown/p001/pages12-13.htm

By "left bank" and "right bank" I'm assuming it means the northern bank and southern bank respectively?

 

I don't understand the bit about the boat on right / north side being brought over to the other side? How would this be possible?

And when leaving the left / south side it implies that no-detaching and re-attaching is necessary which is surely wrong?

 

What I'm thinking happened is this, the rope being walked under the bridge and attached to the horse already on it:

Which is similar but simpler than described, could be used from either lock and surely wouldn't need a 'special' local horse to perform it?

 

Have I got it right, or am still missing something?

 

And then perhaps after this, I'll ask about getting boats into the locks traveling upstream! Would there be enough momentum after the Hampstead Road bridge, or would they be able to be towed in given the short amount of tow path after the access gate from the road? (Shown by the steps next to the road)

 

Many thanks!

BC

 

[Captain Pegg]

17 minutes ago, Battle Cruiser said:

Hi all,

 

Please be kind to me for asking something probably so simple, but I am unsure as to the operation / usage of the roving bridge over the Regent's canal at Hampstead Road lock, which has come about due to me being sure it wasn't used to allow horses to cross without unhitching. It's the towing of boats coming upstream that's puzzling me.

 

 

 

I've tried slowly re-reading this many times but it's only making a small amount of sense!

https://www.locallocalhistory.co.uk/ctown/p001/pages12-13.htm

By "left bank" and "right bank" I'm assuming it means the northern bank and southern bank respectively?

 

I don't understand the bit about the boat on right / north side being brought over to the other side? How would this be possible?

And when leaving the left / south side it implies that no-detaching and re-attaching is necessary which is surely wrong?

 

What I'm thinking happened is this, the rope being walked under the bridge and attached to the horse already on it:

Which is similar but simpler than described, could be used from either lock and surely wouldn't need a 'special' local horse to perform it?

 

Have I got it right, or am still missing something?

 

And then perhaps after this, I'll ask about getting boats into the locks traveling upstream! Would there be enough momentum after the Hampstead Road bridge, or would they be able to be towed in given the short amount of tow path after the access gate from the road? (Shown by the steps next to the road)

 

Many thanks!

BC

 

 

In general the purpose of a roving bridge was indeed to allow the horse to change sides without unhitching.

 

However at locks boats were never braked by use of the horse, far too dangerous for the horse. Hence the requirement for continuous attachment to the towline did not apply at locks so this particular bridge while performing the basic function of a bridge designed to carry the towpath from one side to the other would not have required to be confgiured to allow an unbroken tow. Hence your supposition is probably broadly correct and the name is a bit of a misnomer.

 

I'd guess the horse went beyond the bridge to get a good straight pull of the boat(s) out of the lock.

 

Edited May 6, 2023 by Captain Pegg

[Tacet]

The writer of that piece has got a few things muddled.  Leaving either lock, the rope to the horse would have to pass under the bridge at some juncture.  I suppose the diagonal lay of the bridge would allow a better/ longer pull for a boat leaving the southern lock, before the rope needed to be disconnected, but I am not altogether convinced that is the reason for the diagonal.

There is possibly an issue of terminology.  Roving and turnover bridges are situated where the towpath changes banks.  Some such bridges, such as the lovely ones found on the Macclesfield canal, allow the tow to continue without removing the line.   But which names distinguishes the features is open to discussion....

[David Mack]

2 hours ago, Battle Cruiser said:

By "left bank" and "right bank" I'm assuming it means the northern bank and southern bank respectively?

I assume so. Left/right bank are usually used in connection with rivers, and apply when looking downstream. Of course there is negligible current here, but the author of that piece seems to think that some effort would be needed to turn the barges against the current flow!

 

Since there is (or at least was before the current pedestrian barriers were installed) access under the South end of the bridge I can't really see why the horse of a boat travelling upstream couldn't walk under and then over the bridge in the ordinary way (while the lock was filling) so that the pull to leave the lock can be made from the towpath on the north side.

Edited May 6, 2023 by David Mack

[Battle Cruiser]

Thanks all - I think my mind is coming to rest!

 

Captain Pegg - I think you're right about the name being a nisnomer, and I think the diagonal may have added to giving it a fancy name. And like Tacet I wonder about the reason for the diagonal too, I suspect it's just because that's where the two bits of land were when the railway building came along.

 

Patron - I did wonder about walking the horse round too, but I think there's only access to the bridge from eastern side because of a wall, which is shown on a map and can be seen from later aerial photos. A chap could squeeze through but a horse would be tricky, but he could walk under and pass the rope on the other side.

But that leads to the question why didn't they just build the bridge so it could be used as a proper turnover bridge?! 

[Pluto]

It looks to me that the bridge dates from when they built the two basins on the north side, and that the towpath had previously run on the north side. The map dates from 1870, and by then there could have been capstans for moving boats through locks, with the 'towpath' just being a way of allowing the horse to get around the new basins, and not necessarily for towing. I am sure the London Canal Museum will have the answer.

[Battle Cruiser]

Hi Pluto - the basins were dug when or soon after the canal was cut. The bridge was built when the railway built the interchange building, which is the building with the N/S railway lines and turntables in. Prior to this the towpath left the canal away to the north and rejoined at Hampstead Road. There are capstans still in place at the lock, though well seized up now of course. But there are plenty of deep rope scars on the bridge so rope under load would definitely have been going on

[Pluto]

Thanks, I have now looked through my files and have found a report on the site by Camden Railway Heritage Trust in July 2013, when they were trying to get the bridge listing improved. Most change-line bridges are constructed where the canal moves from one side of a valley to the other, towpaths almost always being on the 'lower' side. However, there is a similar arrangement to that at Hampstead Road,  on the L&LC at Bootle, two change line bridges being installed when the warehouse and arms at Bootle were built circa 1880.

[Battle Cruiser]

Thanks everyone, I think that makes sense now. Although I don't understand why they didn't design the bridge as a true roving bridge. I'm sure they're would've been enough space to use designs 3 or 4, in the below wiki diagram, rather than 1.

 

 

Anyways, what's puzzling me now is how they got the boats going upstream (west) out of the locks before the bridge was built. This map from 1850 shows how far the top of the locks are from the towpath, which I've marked in red and a speculative bit in pink, and the two wharves in the way. 

 

 

Would they have walked a rope round the basins, or thrown them across, to pull the boats out? Or punted them out? Or am I missing an obvious / common solution? Surely they couldn't have pushed them hard enough from the lockside for momentum to keep them going could they? 🤔

Edited May 12, 2023 by Battle Cruiser

[Pluto]

The two things you need to remember is that moving a boat in deep water is comparatively easy, and that once moving they do not require that much additional effort, particularly where distances are comparatively short. The middle lock at Johnsons Hillock (L&LC) has a bridge without a towpath immediately above, with a hook fixed to the wing wall for the tow-line to pass around so that a boat horse could pull the boat out of the lock whilst walking in the opposite direction. When school children visit Kennet, the L&LC Society's short boat, probably weighing 35tons including ballast, they are always amazed at how one child can move the boat.

 

The other thing is that 200 years ago, time was relatively unimportant, and that the volume of traffic had not reached the sort of tonnages that were carried towards the end of the 19th century when steam towage and capstans were beginning to be used. The efficiency of historical structures need to be assessed using the conditions prevailing at the time, and not from modern ideals.

[Machpoint005]

17 hours ago, Battle Cruiser said:

Anyways, what's puzzling me now is how they got the boats going upstream (west) out of the locks before the bridge was built. <<

 

 

I presume there's another bridge somewhere close by, but as for the towrope, the crew could simply walk across the lock gates with it?

[Derek R.]

19 hours ago, Machpoint005 said:

 

I presume there's another bridge somewhere close by, but as for the towrope, the crew could simply walk across the lock gates with it?

No, the bridge carries the main road, and the basins (both sides) prevent continuous towage. Nor does the 'horse/pedestrian' bridge have a facility for continuous towage.

But as Pluto says, pulling or poling a boat out of a lock will give sufficient momentum for a line to be passed either up onto the bridge or tow path to attach to horse or tractor.

[oboat]

On 12/05/2023 at 19:07, Battle Cruiser said:

Thanks everyone, I think that makes sense now. Although I don't understand why they didn't design the bridge as a true roving bridge. I'm sure they're would've been enough space to use designs 3 or 4, in the below wiki diagram, rather than 1.

 

 

Anyways, what's puzzling me now is how they got the boats going upstream (west) out of the locks before the bridge was built. This map from 1850 shows how far the top of the locks are from the towpath, which I've marked in red and a speculative bit in pink, and the two wharves in the way. 

 

 

Would they have walked a rope round the basins, or thrown them across, to pull the boats out? Or punted them out? Or am I missing an obvious / common solution? Surely they couldn't have pushed them hard enough from the lockside for momentum to keep them going could they? 🤔

I agree, a long way for a loaded wide bluff ended London boat to free float. I would have said, your pink line would have joined a swing bridge (may be just pedestrian to maintain momentum and take the rope) over the pre existing railway basin which would have been replaced with the existing Br when the new railway building was built. The wood yard basin was a walk round but again could have had a swing Br. Such a S/Br would also facilitate  use of the basins to the south.  

Edited May 14, 2023 by oboat

[Pluto]

At canal speeds, the shape of the bow has little influence on how a wide boat floats. Out of gear, my old L&LC boat, with its bluff bow, would float much easier than a narrow boat, possibly because of the well shaped run to the rudder. In some cases, what does make a bluff-bowed boat more difficult can be installing an engine, as this increases the flow around the hull, in effect speeding the boat's passage through the water, an effect which increases in shallow/narrow waters. I can't see this as being a major problem on a wide, well maintained canal such as the Regent's in the 19th century.

[Tim Lewis]

As an aside I recently went to the CRT event where they showed off the half million pound restoration of the next towpath bridge upstream of the roving bridge, the one that goes over the entrance to Dead Dog Tunnel. The rope matks on the parapet can be clearly seen.

 

 

Edited May 14, 2023 by Tim Lewis

[Pluto]

A report on Islington Tunnel from the Daily Mail in 1901.

1901-7-26 Daily Mail, Islington Tunnel.pdf

[Battle Cruiser]

On 13/05/2023 at 09:26, Pluto said:

The two things you need to remember is that moving a boat in deep water is comparatively easy, and that once moving they do not require that much additional effort, particularly where distances are comparatively short. The middle lock at Johnsons Hillock (L&LC) has a bridge without a towpath immediately above, with a hook fixed to the wing wall for the tow-line to pass around so that a boat horse could pull the boat out of the lock whilst walking in the opposite direction. When school children visit Kennet, the L&LC Society's short boat, probably weighing 35tons including ballast, they are always amazed at how one child can move the boat.

 

The other thing is that 200 years ago, time was relatively unimportant, and that the volume of traffic had not reached the sort of tonnages that were carried towards the end of the 19th century when steam towage and capstans were beginning to be used. The efficiency of historical structures need to be assessed using the conditions prevailing at the time, and not from modern ideals.

 

Ahhh, that makes sense. There are bollards and even a capstan at the top end of locks - one of which has a fair bit of rope wear round it.

 

Thanks Pluto!

On 13/05/2023 at 12:33, Machpoint005 said:

 

I presume there's another bridge somewhere close by, but as for the towrope, the crew could simply walk across the lock gates with it?

That would just get you to the other side of the locks, still some way from the towpath.