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221:, or ELJs, that may aid in efforts to save stocks of salmon. The sheer mass of the dolosse provides ballast for logs and slash ("wrack" or "rack" organic debris) to create a stable, complex habitat structure, all the while precluding the need for excessive, environmentally-invasive and costly excavation for their placement into substrate.
89:
316:, Southern African traditional healers. The second is a reference to the knucklebones used by African children to play. The name was attached to the objects when Kruger's father, Joe Kruger, who also worked in the harbour, came upon his son and others playing with small models of the objects and asked him
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They work by dissipating, rather than blocking, the energy of waves. Their design deflects most wave action energy to the side, making them more difficult to dislodge than objects of a similar weight presenting a flat surface. Though they are placed into position on top of each other by cranes, over
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The reason for this is uncertain. Two reasons for this have been put forward: one by
Merrifield; the other by Kruger. Merrifield stated that he did not protect them as he wished them to benefit humanity. Kruger alleges that Merrifield received incorrect legal advice: to wit, that as the blocks had
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gained more prominence. Kruger's claim is that he and
Merrifield had considered the shape of concrete blocks to be used to protect East London's extensive breakwaters for the City's non-natural harbour, following a major storm in 1963. Merrifield wished to design a block that did not break up or
233:, one-time East London Harbour Engineer (from 1961–1976). Eric Merrifield lead a team which included Piet Grobbelaar and Jack Badham-Thornhill who collaborated for many years perfecting the design. These blocks were designed to 22 tonne in later years. In the late 1990s the claim of
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states it to be a contraction of 'dobbel osse', or 'gambling' (Afrikaans) 'bones' (from Latin). Boshof and
Nienaber state it to be a contraction of 'dollen os', or 'play' (old Dutch) 'oxen' (Afrikaans). The first is a meaning-shifted reference to
199:, dolosse are used as an artificial reef known as the Dania Beach Erojacks. They are also used to trap sea-sand to prevent erosion. Roughly 10,000 dolosse are required for a kilometre of coastline.
246:. Kruger stated that he went home for lunch, cut three sections from a broomstick, and fastened them with nails into an H-shape with one leg turned through 90 degrees to create the distinctive
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Dolosse are normally made from un-reinforced concrete, poured into a steel mould. The concrete will sometimes be mixed with small steel fibers to strengthen it in the absence of reinforcement.
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The drawings for the first dolos were completed in 1963, based on the shape devised in wood by Aubrey Kruger. The following year, 1964, the first dolos was laid on the port breakwater .
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341: – Bay on the North Coast of California – jetties were reinforced using dolosse in the 1980s maintaining the entrance at one of the world's most treacherous harbor entrances
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shift when struck by the sea; that was cheap; and that did not require precise placement. He said in later years that he wanted a block designed in such a way that it could be
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The individual units are often numbered so that their movements can be tracked. This helps engineers gauge whether they need to add more dolosse to the pile.
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time they tend to get further entangled as the waves shift them. Their design ensures that they form an interlocking but porous and slightly flexible wall.
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shape. Merrifield was intrigued by the object and had Kruger draw a plan. Kruger never formally received credit for the invention. Merrifield won the
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Aubrey Kruger‚ the former East London harbour draughtsman who designed the ingenious dolos sea buffer system 50 years ago‚ died in the city last week.
258:'s Gold Medal. The death of Merrifield (in 1982) has put this controversy beyond proof either way. Aubrey Kruger died in East London on 19 July 2016.
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The design of the dolos is not protected by any form of patent. Merrifield did not take the necessary steps to protect the concept.
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Edge, B.L.; Baird, W.F.; Caldwell, J.M.; Fairweather, V.; Magoon, O.T.; Treadwell, D.D. (1882).
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A man stands next to a dolos, showing its relative size. Dolosse moulds are in the foreground -
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from a body of water. The dolos was invented in 1963, and was first deployed in 1964 on the
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been designed during office hours while he was employed by the State (
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Durban's South Pier with a line of interlocking dolosse, South Africa
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The design of the dolos is usually credited to the South
African
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Associated
Science and Technology Societies of South Africa
301:(plural: dolosse). This word has two given derivations.
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McPhee, John (2011). "The
Atlantic Generating Station".
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POSIBLOC™ system for placement aid of concrete blocks
534:"SA inventor of dolos sea buffer system dies aged 82"
498:"The full story behind the dolos and its SA creator"
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472:"Failure of the breakwater at Port Sines, Portugal"
595:"SA world-famous dolos designer dies in home city"
272:South African Railways and Harbours Administration
274:), he was unable by law to protect their design.
92:Dolosse forming a protective structure against a
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209:Dolosse are also being used in rivers in the
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136:for protection against the erosive force of
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347: – Static anti-tank obstacle defense
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76:Learn how and when to remove this message
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191:They are used to protect harbour walls,
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39:This article includes a list of general
661:. London and New York: Frederick Warne.
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322:What are you playing at with the dolos?
546:from the original on 26 February 2018
510:from the original on 26 February 2018
432:Smith, Jane McKee, ed. (April 2007).
286:Plastic playing pieces from the game
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19:For the mythological character, see
371: – Concrete breakwater element
365: – Concrete breakwater element
359: – Concrete breakwater element
353: – Concrete breakwater element
116:used in great numbers as a form of
741:Integrated coastal zone management
593:Hollands, Barbara (26 July 2016).
45:it lacks sufficient corresponding
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624:Martin Creamer's Engineering News
532:Barbara Hollands (27 July 2016).
1038:Wave-dissipating concrete blocks
759:
659:Encyclopaedia of Southern Africa
310:used in divination practices by
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496:Terry Hutson (10 August 2016).
114:wave-dissipating concrete block
318:Wat speel julle met die dolos?
1:
642:. Farrar, Straus and Giroux.
442:. pp. 4806, 4810, 4812.
293:The name is derived from the
148:, a South African port city.
132:), dolosse are used to build
630:South African Financial Mail
997:Modern recession of beaches
440:World Scientific Publishing
240:"sprinkled like children's
16:Concrete breakwater element
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160:Dolos construction yard -
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195:and shore earthworks. In
1043:South African inventions
982:Geotechnical engineering
657:Rosenthal, Eric (1961).
435:Coastal Engineering 2006
215:United States of America
951:Sand dune stabilization
231:Eric Mowbray Merrifield
60:more precise citations.
569:"Dania Beach Erojacks"
476:Isbn 978-0-87262-298-2
415:South African Panorama
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618:Eastern Cape Dispatch
411:"Bastions of the Sea"
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1028:Coastal construction
903:Van der Meer formula
573:Sink, Florida, Sink!
376:Notes and references
225:Credit for invention
197:Dania Beach, Florida
1033:Coastal engineering
992:Longshore transport
808:Cliff stabilization
731:Coastal engineering
124:. Weighing up to 8
1002:Stream restoration
853:Honeycomb sea wall
736:Coastal management
710:Coastal management
639:Giving Good Weight
626:, 16 February 2001
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252:Shell Design Award
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120:. It is a type of
118:coastal management
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1023:Civil engineering
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946:Living shorelines
941:Dynamic revetment
931:Beach nourishment
858:Hudson's equation
649:978-0-374-70857-3
632:, 3 December 2004
262:Design protection
211:Pacific Northwest
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550:26 February
514:26 February
481:17 February
455:26 February
193:breakwaters
162:Yzerfontein
146:East London
58:introducing
1017:Categories
818:Flood wall
803:Breakwater
751:Submersion
718:Management
604:2016-07-27
320:(English:
142:breakwater
134:revetments
130:short tons
41:references
878:Revetment
823:Floodgate
798:Breachway
783:Accropode
726:Accretion
539:TimesLIVE
369:Accropode
295:Afrikaans
108:(plural:
98:Cape Town
94:shoreline
66:July 2012
893:Tetrapod
544:Archived
508:Archived
363:Tetrapod
328:See also
313:sangomas
254:and the
219:log jams
122:tetrapod
888:Seawall
778:A-Jacks
578:3 March
213:of the
112:) is a
110:dolosse
54:improve
883:Riprap
833:Groyne
828:Gabion
646:
446:
334:Riprap
174:Durban
126:tonnes
43:, but
913:Xbloc
908:Wharf
863:KOLOS
843:Levee
838:Jetty
813:Dolos
788:Akmon
357:KOLOS
351:Xbloc
299:dolos
297:word
288:Jacks
248:dolos
242:jacks
138:waves
128:(8.8
106:dolos
21:Dolus
873:Pier
868:Mole
644:ISBN
580:2013
552:2018
516:2018
483:2019
457:2018
444:ISBN
503:IOL
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