congre chariot arcachon congre chariot arcachon congre chariot arcachon
Jean DUFAU  

Personal website

  |  Arcachon

 (D by google)    
T h e    C  H  A  R  I  O  T

A  b i z a r r e   m a c h i n e
le chariot Arcachon en surface
"This machine does look threatening! Actually it is a peaceful subsea-sled
 that will embed sewage pipes off the coast, starting from La Salie beach..."

V  I  D  E  O 

Why I love diving the CHARIOT in 10 seconds

The Film II
Sunfish dancing thanks to Corinne & Laurent
The Film 1

P  H  O  T  O  S  

Among other pictures from Arcachon

P  R  E  S  E  N  T  A  T  I  O  N  

carte Arcachon plongée chariot
Arcachon Bay is located on the Atlantic coast, South West of France, 80km (50miles) from Bordeaux.

The CHARIOT is a  wreck which lies off the Arcachon Bay, at about 3 km (1.6 n.mile) from the coast.

It's a very nice dive. The wreck is a weird submarine machine, used for sea bed works, which is there since the early 70's.

There is a shoal of hundreds of bib
as well as tenths of conger eels and large numbers of bass that make the wreck its home .
A diver can focus only on dense fixed fauna and flora during the dive and that's not due to nitrogen narcosis: the wreck is only 30 metres (98ft) deep.

Too nice to be true? Well actually there are sometimes some difficulties: they are named les passes. These narrow channels are the only way to go out of the bay and reach the sea. They can be dangerous and conditions at sea have to be perfect to avoid any risk. Sometimes the boat has to return after a cancelled dive, but at least there are nice beaches in the area to spend some good time.

D I V I N G   C E N T R E S

Professionnal : Pyla Plongée

 ... and  some others  I don't know.

H  I  S  T  O  R  Y  

At the beginning was a decision to create a sewerage system around the Arcachon bay.

Inland construction site 1968 - 1971
The first work was to build a 30 km pipe in order to avoid the sewage of a paper factory to be rejected into the bay. Then the sewage were driften to a beach called La Salie and rejected directly to the ocean. 

Offshore Underwater work  1970 - 1972
The German company Rudolf HARMSTORF - Wasserbau GmbH  was selected in 1970.
The job was to embed a sewage pipe 5500m off the coast and to connect a diffuser-pipe, a 200 meter long steel pipe with holes to diffuse the sewage water of Arcachon.
The sewage pipe made of high density polyethylene was 1.20m diameter and embedded 2m under sea bed which is 25 to 30 metres deep.

The embedding was based on patented Hydrojet-Injektor technology. Primarily a water jetting device excavate a narrow but deep trench for the pipes; moving forward it fluidized the soil while embedding the pipe which leaves the Injektor foot at the rear end.
The Injektor in the Arcachon project was installed on a subsea-sled now called Le CHARIOT
(see also"Some technical details").

A long period of strong gale and a state of high sea prevented the embedding of the sewage water pipes.Two diffuser-pipes were broken by storm. Embeddment schedule was delayed.

During the work, at least 4 serious diving accidents occurred, 2 of them were fatal.

"Arcachon: solidarity network for a diver...carried by boat, a paralysed diver in decompression chamber to be evacuated by plane to hospital..."
accident plongee

So, the diffuser pipe was not installed yet. The upcoming of smelly foams at La Salie beach in 1971 provoked strong reactions and also became a place for... Sunday promenade!

Finally the construction site was predicted to end soon...

    "...Harmstorf company prepared for second round..."

article sud ouest le chariot

    "La Salie beach: it is almost finished..."
article journal sud ouest chariot

At the begining of 1972, the end of the work is in sight. Dollar devaluation and Mark revaluation will have an unexpected consequence for HARMSTORF: the company got bankrupt. At the same moment the company was involved in a big construction site in Bremen and had to face huge financial loss in Anchorage Alaska.

    "...Harmstorf get bankrupt..."
"article Chariot arcachon journal sud ouest

Then, the embedding had to stop 3 km off the coast, and finally the sled (Le Chariot) was left at this position... for the pleasure of today's divers and fishermen.

Le wharf 1972 - 1974
A new solution had to be found. It was a different system: a wharf.
The wharf is a pier holding the sewage pipe above the water rather than belowIt is 800m long and is made of 1.50m diameter pipes. It is on duty since April 1974.
Sewage of towns situated around the bay are now collected after treatment and brought to the  wharf by a 65 km pipe. 
The continuous water
treatment improvements are facing increased concerns about environment.
An interesting debate can be followed (in French) on the Internet.

wharf de la salie du sol

le wharf de la Salie vu par Géoportail
rcachon principe

S O M E    T E C H N I C A L    D E T A I L S

 The supply vessel without water-pipes, off the coast of Arcachon.
barge chariot Arcachon

Chariot et barge Arcachon

 How the whole system works
Chariot Arcachon principe

The Injektor in the Arcachon project was installed on a subsea-sled with more than 200 tons, similarly to the sled on the following drawing.
Chariot Arcachon principe
On this drawing a cable is installed into the seabed, instead of water pipes. It is however in principle the same technology.

For more information click 

Brochure from Harmstorf company 

Logo Harmstorf

Harmstorf family has a long history in the Diving and Salvage business.
 In 1870 Friedrich Matthias Harmstorf started as the first diver on the river Elbe near Hamburg
   His son Alnwick Harmstorf, a diver too, invented in 1926 the technology to embed cables into the seabed by the so called Injektor with water pressure.
  The grand son, Rudolf Harmstorf took over and further developed this technology around the world. In France, the company has burried many cables and pipes between 1954 and 1971.

   After the company went bankrupt in 1972, it was again established by Rudolf Harmstorf in 1975 and worked successfully world-wide until sold to Britisch Telecom / Cable&Wireless in 1992. 

T  h  a  n  k  s   -  R  e  f  e  r  e  n  c  e  s
A big "Danke" to Heinz Harmstorf for documentation, to his father Rudolf who let us a so nice wreck.

Special thanks to Gérald PUEL with who I made my first dive
in 1998 on what was then called "la chenillette" the caterpillar.

Syndicat Intercommunal du Bassin d'Arcachon (SIBA)

Bordeaux public library
Archives départementale de la Gironde
Archives de la mairie de La Teste
SUD-OUEST newspaper
La Dépêche du Bassin newspaper
Web sites Géoportail and Earth Google

Thanks to link this page if you use some piece of information 

Found my English a bit...weird ? E-mail me, I will correct ;-)  @