7mm Heybridge Basin

[Richard Gawler]

The only thing which keeps putting me off at present of the use of baseboard kits is their use of apparent heavyweight materials and construction to withstand earthquakes. With this in mind I always keep looking at aircraft wing design and construction to see if I can build strong lightweight baseboards.

The Grainge and Hodder modules use 6 mm birch ply. I think this is the best compromise we can have. Thicker material e.g. 9 mm ply is too heavy, and MDF of any thickness absorbs moisture, sags and is unstable in the long term. The largest G&H module is 1,200 x 900 mm and I think this is the largest size you could expect to make from 6 mm ply and end up with enough rigidity.

I find woodwork terribly difficult as soon as the subject is too large for my workbench. Marking out and assembly often happens on the floor, and this is backbreaking and tiring. The G&H kits are really easy to put together, and you can add corner blocks and diagonals as needed to finish the job. The longer modules tend to invite a two-man lift and this can bring twisting forces, so I would always fit corner blocks into these to reinforce the most vulnerable joints.

At moment "Heybridge Basin" weighs 2.9 kg (minus the front trim for the basin) so supposing the model adds as much again, the result should still be very manageable single-handed.

 

[adrian]

The Grainge and Hodder modules use 6 mm birch ply. I think this is the best compromise we can have. Thicker material e.g. 9 mm ply is too heavy, and MDF of any thickness absorbs moisture, sags and is unstable in the long term. The largest G&H module is 1,200 x 900 mm and I think this is the largest size you could expect to make from 6 mm ply and end up with enough rigidity.

Going back a few years now, I made a large board for the kids Hornby set from 4mm ply, just because it's what I had in the shed at the time. To improve rigidity on a delta wing aircraft fin the spars are curved in an S shape. So with that inspiration I did the same with the under board diagonal bracing. Instead of straight bracing battens I cut them over length, being 4mm ply there was a nice little bit of flex in them and would bow nicely when fitted. No nails or screws used just clamped in position and glued. That produced a remarkably torsionally rigid lightweight board.

 

[Richard Gawler]

Yes I have quite surprised myself at the strength of my "overhanging rear extension" now the moulding at the back is fixed into place.

I forgot to mention, I used a long strip of 4 mm ply as a flexi curve to set the cutting line. I held the strip in compression while a helper drew in the line for cutting. This would have been near impossible to do single-handed.

The 4 mm ply is the thickest ply I can bend, but I find it too thin to accept a pin into its edges. Pins always go in crooked and emerge to catch on fingers, so I end up with corner blocks and other bits of softwood and thicker ply to hold things into place.

 

[Richard Gawler]

Yes it can be turned into a nice piece of furniture. With this in mind, and to match the pine edge mouldings have you used, have you considered using iron-on wood veneers for the fronts, outer ends, and rear of the baseboards to hide the ugly burnt (to me anyway) laser cut joints to finish the outer edges?

I had not heard of such veneer - it sounds like a good idea. My experience is limited to the iron-on edging for chipboard. I have got to give it a try, so I will defer track laying until I have had a go.

In the meantime I can have a go at mocking things up.





CA glue = water column
Wood glue = mature tree
Coles crane = crane on loading platform
Polystyrene block = small boat

The headshunt can take Nellie (or Blackwater or Lady Marion) and one wagon.

If there is a passenger train here at the same time, things are plenty crowded. I am thinking of scenery being the water and the ground surfaces; perhaps a boundary fence along the curved edge (as long as it doesn't get in the way) and to be honest not much else.

 

[Alan]

Don't forget the ship Inn next to the lock or the Jolly Sailor about 50 yards away.

 

[Richard Gawler]

Don't forget the ship Inn next to the lock or the Jolly Sailor about 50 yards away.

Also the cottages next to The Old Ship.

I am thinking, backscene or (possibly) a scenic-only module at the far end of the baseboard. I have no idea how to carry off either; this will be my first scenery in 7 mm scale.

I do know, on a scale of happiness with a soldering iron at one end and an artist's canvas at the other, a talented artist living nearby might be the right person to approach for a backscene. Even if they usually do Panniers

 

[Alan]

Sensible person, the artist that is.

 

[Richard Gawler]

I think the best way to include The Old Ship will be to provide an extension section something like this:



Steel rule = front of sea lock
UHU = lock gate
Biscuit tin = pub

The longer headshunt now holds a loco and three wagons, or I suppose just about any British loco if wanted for photography.

The water level in the sea lock would look good modelled below the water in the basin. I rather like this. I especially like the look created using a straight rear edge at each end of the curved rear edge, but the effect is difficult to convey in photos.

 

[Yorkshire Dave]

The water level in the sea lock look good modelled below the water in the basin. I rather like this. I especially like the look created using a straight rear edge at each end of the curved rear edge, but the effect is difficult to convey in photos.

Not only that, it'll also give you the opportunity to model fresh and sea water being different colours as this aerial view of Heybridge shows.

 

[Richard Gawler]

I must remember to model the water in the lock below the level of the water of the basin, as if at sea level.

 

[Dog Star]

Or the level in the lock higher than the mud in the estuary as if the tide is out?

 

[Richard Gawler]

Graham, I am rather struggling to understand your question

• The level of the water in the sea lock is always either level with the water in the basin, or something lower than this.
• When the tide is out, the channel in the estuary is not navigable.
• Just how low the water level in the lock is allowed to go I do not know. Perhaps, very low indeed if the canalised part of the Chelmer is in flood and there is a need to remove surplus water from the Navigation.
• The lock contains mostly fresh water after being filled from the Navigation; and (if the tide is high enough to be navigable) mostly sea water after being opened to the estuary.

I can ask at a future site visit but any information I receive will reflect preset-day practice, not Victorian practice. It seems a bit academic to making a model where all I can hope to show is a difference in water levels.

I hope this helps all the same

 

[Yorkshire Dave]

Graham, I am rather struggling to understand your question

I think Graham means the water level in the lock chamber being at basin level with the sea at low tide. However in the period you're modelling I don't think there would have been much mud and silt visible at low tide as the channel would have been maintained and much wider than it appears today.




I've also done a bit of digging and found out the sea lock was extended in the 1960s to the gates in the photo above to allow coasters into the basin. The gates seen today replaced the 1960s chain operated sliding gate - Heybridge Sea Gate & Lock Gate Replacement (2017) | Water Projects. From the aerial photo it appears the outer seaward gates remain operational to allow vessels longer than 60' into the basin and in all other cases the original 60' lock is used. And apologies - as you probaly know all this anyway.

When it comes to the model you can have the water level in the lock chamber anything between the basin and high or low tide..... making sure the relevant set of lock gates are open or closed or even both sets open on a high tide. My preference would be to model the lock with the sea lock gates open at low tide so you can have the damp lock chamber with it's seaweed visible and the channel at low tide.

 

[Overseer]

I think Graham means the water level in the lock chamber being at basin level with the sea at low tide. However in the period you're modelling I don't think there would have been much mud and silt visible at low tide as the channel would have been maintained and much wider than it appears today.


View attachment 209360

I've also done a bit of digging and found out the sea lock was extended in the 1960s to the gates in the photo above to allow coasters into the basin. The gates seen today replaced the 1960s chain operated sliding gate - Heybridge Sea Gate & Lock Gate Replacement (2017) | Water Projects. From the aerial photo it appears the outer seaward gates remain operational to allow vessels longer than 60' into the basin and in all other cases the original 60' lock is used. And apologies - as you probaly know all this anyway.

When it comes to the model you can have the water level in the lock chamber anything between the basin and high or low tide..... making sure the relevant set of lock gates are open or closed or even both sets open on a high tide. My preference would be to model the lock with the sea lock gates open at low tide so you can have the damp lock chamber with it's seaweed visible and the channel at low tide.

The outer gates are flood gates in a levee to prevent high tides flooding the area. Note they are hung the opposite way round to the lock gates.

From time spent hanging around and using Bow Locks on the River Lee and the Limehouse Basin lock the outer lock gates would always be kept closed at low tide, with water in the lock, to stop silt entering the lock with the incoming tide. Each tidal lock has a minimum draft it can be used at, usually above half tide so the lock would almost never be seen empty.

 

[Richard Gawler]

Heybridge Basin has two pairs of lock gates, a pair of hinged sea gates (which face in the opposite direction), and a sliding dam. So, four sets of gates in all.


The present dam was installed as part of the works in 2017.

I took this photo for amusement because the brand-new display of information for the public was fenced off and impossible to read.


This display calls the dam a "sea lock gate" and calls the pair of sea gates the "lock gates".

The article linked by Dave correctly calls the original dam (now removed) "a steel caisson outer gate" but calls its replacement "a sea gate". This article then gets difficult to follow because it calls the pair of hinged sea gates "mitre gates", "lock gates" and "sea gates"!



During these works, the dam was closed to allow renewal of the hinged sea gates, and it remains in place and operational so they can be isolated from the sea at high tides. This satellite imagery on Bing Maps shows the dam closed and the sea gates open, but I don't know the circumstances. The ground looks parched, so perhaps mid or late summer.

For clarity, The Old Ship is located on the corner between Lock Hill and Basin Road, and not at the orange marker here.

 

[James Spooner]

Richard,

The aerial photo you have just posted brings childhood memories flooding back. My parents used to drive us to Heybridge Basin on a fine summer Sunday morning for a walk along the coastal path and then back to the Old Ship for drinks (in those days that had to be carefully timed due to Sunday opening hours!). Most visits there would be, what seemed to me as a small boy, a large ship (in reality probably only a few hundred tons) that on Monday would continue unloading its cargo of Scandinavian timber, I guess largely for transhipping on to Brown’s yard at Chelmsford. Judging by the photo with three banks of pleasure yachts moored up, I suspect that trade ceased years ago. Does anyone know when it stopped?

Nigel

 

[Richard Gawler]

According to the book by John Marriage, "The Chelmer and Blackwater Naviagation", Brown's finally stopped using the waterway in 1972. The proprietors then decided to open the waterway for pleasure traffic.

From my other notes - this was six years after the closure of Witham to Maldon railway to freight traffic in 1966, and indeed two years after the cessation of the bus service, introduced in 1964 to replace the lost passenger train service.

 

[Richard Gawler]

The satellite imagery on Google Earth shows how the sea lock has been rebuilt after it was rebuilt in the 1960s.


In 2000, the lock was recorded in its original extended form. The lower lock gates (now restored) have been removed, and the lower gate is the floating caisson.


By 2005, the lower lock gates had been reinstated. These were renewed during the works of 2017/18.

There are many other images of the lock on Google Earth, but not quite enough to draw a conclusion on how all of the gates are worked nowadays during normal operation.

 

[James Spooner]

The satellite imagery on Google Earth shows how the sea lock has been rebuilt after it was rebuilt in the 1960s.

View attachment 209383
In 2000, the lock was recorded in its original extended form. The lower lock gates (now restored) have been removed, and the lower gate is the floating caisson.

View attachment 209384
By 2005, the lower lock gates had been reinstated. These were renewed during the works of 2017/18.

There are many other images of the lock on Google Earth, but not quite enough to draw a conclusion on how all of the gates are worked nowadays during normal operation.

Thanks Richard and the upper photo in this post shows the lock as I remember it. I guess those timber carrying ships were too big for the original sized lock, hence the sliding lock gate being built nearer the sea. I do remember Dad stopping the car at Maldon East station just before it shut for freight and making some drawings in case he ever decided to make a model of it…

Nigel

 

[Richard Gawler]

Not only that, it'll also give you the opportunity to model fresh and sea water being different colours as this aerial view of Heybridge shows.

The outer gates are flood gates in a levee to prevent high tides flooding the area. Note they are hung the opposite way round to the lock gates.

Heybridge Basin has two pairs of lock gates, a pair of hinged sea gates (which face in the opposite direction), and a sliding dam. So, four sets of gates in all.

I have had a field trip at low tide this morning, and I spoke with the lock keeper

The two hinged sea gates (the gates facing in the opposite direction) are as Fraser @Overseer points out the flood gates. They belong to the Environment Agency. They are closed during exceptional tides, and their purpose is to prevent the community of Heybridge Basin from flooding.

The sliding gate belongs to Essex and Suffolk Water. This gate has an extra bit along the top, purpose not entirely clear, which makes the structure look much the same height as the two flood gates.

So, it seems this photo posted by Dave shows an unusual circumstance; the tide is not particularly high but the flood gates are closed.


This morning, the flood gates were open and all the other gates were shut.


None of this makes modelling any easier, but I have taken plenty of photographs.