Defence photos on Flickr

Port Winston at Arromanches, the Mulberry harbour a British type of temporary harbour developed in World War II to offload cargo on the beaches during the Allied invasion of Normandy.

francemoblie.blogspot.com/2011/10/france-sep-2011-day-ele...

Defence by Gary Danton

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Sea defences, Eccles-on-Sea, Norfolk. August 2011.

Shot with a Holga 120N and Ilford HP5+

Image by Gary Danton - garydanton.co.uk

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Defence! by andrickthistlebottom

Academy self defence by Gordon Cook

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Pictured in Arbroath Academy in July, 2004 was Mark Cooper SJN Marshall Arts Academy, coaching a class in self-defence and kick boxing.

WW1 Pillbox (1) TG299305 071121 by Chris Pyrah

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By the Mill Lane bridge over the North Walsham & Dilham canal, part of the River Ant stop line.

Australian Defence Forces by dr drey + megs

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Untagged, La Défence by Hanne Therkildsen

Untagged, La Défence, Paris

IMG_8537 by shay connolly

Defence forces at farmleigh

AMANI AFRICA II - Main planning conference by CSDP EEAS

The Wall by Sam Chapman

This is the friendly inside….

Defence by Adrian Dumitru

WWII, Coastal Artillery Searchlight, Wellington Road, Harwich. by Stuart Banham

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Between 1890 and 1914 Defence Electric Lights were all under the control of the Royal Engineers. Responsibility for these Electric Lights subsequently passed to the Coastal Artillery after World War One, who renamed them as Coastal Artillery Search Lights (CASL). Electric Lights had been used in warfare from 1853 but by the early 1870's the technology was beginning to develop sufficiently for effective deployment. The British Defence Electric Light was introduced in the late 1880's and the Manual of Electric Search-Lighting published in 1890 by the School of Military Engineering, Chatham. This is primarily a technical book but there is a brief chapter on the ''Tactical Use of the Electric Light''. It is suggested that the Electric Light can be used not only to locate the enemy but also to prevent the enemy seeing you by obscuring his vision.

The use of Electric Lights to locate an enemy is identified as:

▪︎Search / Sweep Light - A moving light to sweep an area.

▪︎Fixed Beam Light - A fixed beam across an area that the enemy must traverse.

▪︎Sentry Beam - By illuminating a distance rock or shoreline so that the enemy can be seen when they cross the light beam.

The light could of course be used both to cover sea approaches or a land front.

The Role of the DEL was defined in these manuals as being:

▪︎Search Light to sweep and area to the front of the searchlight to detect any enemy movement withing this area. The majority of coastal defence DELs were this type of Fighting Light.

▪︎Fixed Beam Light or Sentry Light which covered a fixed area to its front. This could be to cover a boom defence, minefield, or road.

▪︎As a dispersed light with a broad strip of illumination to the front of a given location.

▪︎In the Coastal Defence role, the primary use of the DEL was to locate and then track the movement of any hostile vessel.

By the middle of the 1890's after some experimentation the British had settled on the 90cm light as the most appropriate for Coastal Defence Work. A common model was the Siemens Projector which had the following specifications:

▪︎Light Beam: Two Billion candles

▪︎Rang: 11,975 feet

▪︎Method: 3 foot diameter carbon arc projector type using a parabola-ellipse reflector.

The light was created by the electric burning two carbon rods, parts of these rods can still be found at some sites. The coastal artillery searchlight would have been fitted with a converted 3ft Anti-Aircraft Searchlight Unit, which were in plentiful supply during World War Two. Running on 90 Volts direct-current, and drawing around 120 Amperes from a Lister generator used to power it, these searchlights utilised nearly 11 Kilowatt power-consumption to throw out a stabbing pencil-beam equating to just short of 2 Billion Candle-Power !

The Defence Electric Lights required electric power, and this required comparatively large engine rooms with one generator allocated to each projector, with one generator as a back up. Initially steam power was used, but it took two to three hours to get up a head of steam, clearly to long if facing a surprise attack ! By 1894 paraffin and oil was quickly adopted as an alternative and these generators only took two hours to become effective. The Engine Rooms tended to be concentrated within forts and batteries in underground or casemated chambers for protection. Often, such as at Fort Carlisle in Cork, old heavy RML casemated positions were used. Considerable importance was place on DEL's and they were often placed under the control of a Searchlight Director Station (SLDS). This Directing Station was required to coordinate the use of the searchlights with the artillery gunners engaging any targets.

The DEL's were initially mounted in simple rectangular emplacements with a single large window facing seawards, fitted with steel shutters for protection. Entry to the position was usually from a covered entry to the rear. By 1900 it was realised that the small aperture to the front of the building limited the arc in which the searchlight could be turned. The new design saw a more complex building with a large semi-circular front with steel shutters that could be moved back to the sides and a small radio room was also added.

It was quickly realised that Defence Electric Lights were highly vulnerable to hostile fire so various methods were adopted including:

▪︎The provision of steel shutters to cover the projector.

▪︎Attempts were also made to conceal lights in dead ground such as the fixed beams lights close to the shore line.

▪︎Adoption of the ‘Port Hole’ lens which was fitted over the front of the projector to give a concentrated beam, allowing the light to pass through a narrow opening in armour plate before opening out again into a wider beam.

▪︎The see-saw searchlight which allowed the projector to remain covered in a bunker, with the light projected from a mirror on a beam that could be moved up and down. The see-saw searchlight proved extremely hard to operate effectively in combat conditions and were not widely adopted.

Sourced from:

pinkroutes.org/research/defended-ports/port-defence/defen...

LAAD Defence & Security 2019 by Roberto Caiafa

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Fotos Roberto Caiafa

Tsunami defence by gilesh