Slipway and Caisson support foundation T2 & T3

Slipway and Caisson support foundation T2 & T3 (82163)

Easting
446584
Northing
98885

Description

This Feature is one of 8 slipways and the adjacent support foundations labelled T2 & T3 on a (circa) 1994 survey. The concrete foundations are a key part of the method of launching caissons at Lepe. The foundations are the points at which the weight of the caisson is transferred from a continuous rail (the production line) to the launch slipway. On the 6 June 1944 thousands of troops with their vehicles and supplies left Britain via locations such as Lepe Beach in the New Forest for the beaches of Normandy. This was D Day, the start of the great campaign to liberate Europe and to bring the Second World War to its end.

During a Citizan survey day at Lepe on the 5th August 2016 the team did a number of measurements and surveys of the slipways. A drawing was also completed of the foundations T2 and T3 (referenced from a 1994 survey).

The interpretetation of some of the features found (and shown on the drawing in photo1) are detailed below.-

The concrete foundations shown in the diagram are a key part of the method of launching caissons at Lepe. The foundations shown (1 of 8) are the points at which the weight of the caisson is transferred from a continuous rail (the production line) to the launch slipway.

In order for the caisson to clear these concrete foundations on its way down the slipway they are built lower than the adjacent foundations by about half a metre. A removable steel bridge to support a rail could have been constructed across the tops of all the foundations such that the rail could be continuous (and at the same level as the production line). The steel bridge and rail would have been temporarily removed once the weight of the caisson was transferred to the slipway.

The steel bridge would have been bolted to the concrete foundations at points B and the ends or feet would rest against the plates at points A (such that the concrete is not gouged). The steel plates that were mounted on top of the concrete block at points C were rests for the steel bridge to help spread the weight of the caisson evenly across the foundation. There are very few fixings (bolts) near the weight bearing steel plate which indicates that it was relatively easy to deconstruct the bridge prior to launch of the caisson.

The metal tray shown at E may have been positioned to give some protection to a winch cable. (The tray is not load bearing since it is was produced in a short length – approx 2 metres).

The compete launch slipway is likely to have been 8 massive steel box girders similar to those shown in the photo at stokes bay (under construction). The ‘straps’ attached to the girder were likely to be flexible anchor points which were possibly attached to the steel brackets (e.g. point D) mounted on concrete foundations.

There is additional photogrammetry of this slipway and foundations at.-

https://skfb.ly/XO8P https://sketchfab.com/models/a449b175523a40a688df245241edacd2


Periods
Period
Modern (1901 and later)
Period comments

On the 6 June 1944 thousands of troops with their vehicles and supplies left Britain via locations such as Lepe Beach in the New Forest for the beaches of Normandy. This was D Day, the start of the great campaign to liberate Europe and to bring the Second World War to its end.

Specific Date Range
The earliest date of the feature, as a year, if known
1944
The latest date of the feature, as a year, if known
Feature Types
Monument Type - Broad
Military installation
Monument Type - Narrow
Monument Description
Evidence Type - Broad
Structure
Evidence Type - Narrow
Extant
Evidence Description
Man-made roofless edifice or construction which is intact or substantially intact, with significant survival of original features, even if no longer serving original intended function.
Object Type - Broad
Object Type - Narrow
Object Description
Other:
Height OD (m)
1.00
How accessible is the feature?
Easily accessible - no restrictions
Accessibility comments

Other records:

NRHE Number
Unknown
NT HBSMR Number
Unknown
HER Event Number
Unknown
External Link
None

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Feature Update Surveys

2 surveys accepted and 0 pending.

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Survey Information
Date of survey
5th August, 2016
Feature located?
Yes
State of the tide
Mid
Proximity to coast edge
Intertidal zone
Coastal processes
Active sea erosion
Is there a coastal defence?
No
Other threats?
Structural damage/decay, Water erosion (e.g. stream, etc)
If other, please specify
How visible are the remains? ABOVE GROUND
Highly visible (substantial remains)
How visible are the remains in the face of the cliff, ridge or dune? IN SECTION
Clearly visible in section
Do you know if the feature is?
Is well known, Is well visited, Has local associations/history
Recommendations and Comments
What actions (if any) would you recommend for this feature?

Storm waves/tides will undercut the foundations eventually leading to subsidence and breakup. There have been loose metal fabrications/brackets/etc that have detached from their mountings and been washed away or removed. These fittings give clues as to how the launch system for the giant caissons functioned. It would be interesting to discover any fixings or holes in the sides of the concrete slipways at Lepe that may have been fixing points for ‘straps’.


Do you have any other comments?

During a Citizan survey day at Lepe on the 5th August 2016 the team did a number of measurements and surveys of the slipways. A drawing was also completed of the foundations T2 and T3 (referenced from a 1994 survey).

The interpretetation of some of the features found (and shown on the drawing in photo1) are detailed below.-

The concrete foundations shown in the diagram are a key part of the method of launching caissons at Lepe. The foundations shown (1 of 8) are the points at which the weight of the caisson is transferred from a continuous rail (the production line) to the launch slipway.

In order for the caisson to clear these concrete foundations on its way down the slipway they are built lower than the adjacent foundations by about half a metre.

Photo1 - Shows difference in height

A removable steel bridge to support a rail could have been constructed across the tops of all the foundations such that the rail could be continuous (and at the same level as the production line). The steel bridge and rail would have been temporarily removed once the weight of the caisson was transferred to the slipway.

Photo2 - Plan of bay between T2 & T3

The steel bridge would have been bolted to the concrete foundations at points B and the ends or feet would rest against the plates at points A (such that the concrete is not gouged). The steel plates that were mounted on top of the concrete block at points C were rests for the steel bridge to help spread the weight of the caisson evenly across the foundation. There are very few fixings (bolts) near the weight bearing steel plate which indicates that it was relatively easy to deconstruct the bridge prior to launch of the caisson.

The metal tray shown at E may have been positioned to give some protection to a winch cable. (The tray is not load bearing since it is was produced in a short length – approx 2 metres).

Photo3 - Plan of bay between T2 & T3

The compete launch slipway is likely to have been 8 massive steel box girders similar to those shown in the photo at stokes bay (under construction). The ‘straps’ attached to the girder were likely to be flexible anchor points which were possibly attached to the steel brackets (e.g. point D) mounted on concrete foundations.

http://www.friendsofstokesbay.co.uk/wp-content/uploads/2016/06/phoenix3.jpg

It would be interesting to discover any fixings or holes in the sides of the concrete slipways at Lepe that may have been fixing points for ‘straps’.

Photo4 - Slipway between T2 & T3

There is additional photogrammetry of this slipway and foundations at.-

https://skfb.ly/XO8P https://sketchfab.com/models/a449b175523a40a688df245241edacd2

BPN 2016


Survey Information
Date of survey
19th April, 2018
Feature located?
Yes
State of the tide
Proximity to coast edge
Less than 10m inland
Coastal processes
Is there a coastal defence?
Other threats?
If other, please specify
How visible are the remains? ABOVE GROUND
Limited visibility (partial remains)
How visible are the remains in the face of the cliff, ridge or dune? IN SECTION
Not applicable
Do you know if the feature is?
Recommendations and Comments
What actions (if any) would you recommend for this feature?

Do you have any other comments?