The Lavrio-Syros II project concerns the second interconnection, between Syros and the Greek Mainland (Lavrio, Attica). This project is the third phase of the Interconnection of the Cyclades to the Greek Mainland Grid.

In summary, the submarine cable route has a length of approx. 108km and a maximum sea depth of approximately 300 meters. The underground part of the 150kV AC Transmission Line on Lavrio side is approximately 1050m long, while the underground part of the 150kV AC Transmission Line on Syros side is approximately 600m long.

Nexans has awarded ASSO a contract for the execution of pre-lay mattresses installation, the submarine cable protection up to 100m w.d. and additionally the landfall preparation and assistance.

 ASSO’s scope of work included:

  • Preparation Activities // Mobilization Activities 
  • Pre-excavation - Onshore 
  • Pre-excavation - Nearshore/Shallow Waters 
  • Pre-lay Mattresses Installation 
  • Pre-trenching - Offshore/Deep Waters (Syros side up to 100m w.d)
  • Post-lay Burial Operations (Lavrio side up to 100m w.d) 
  • Landing Assistance 

Vessel/Equipment used:

  • Aethra 
  • Ariadne 
  • Astrea
  • Alcyone
  • AssoJet III
  • AssoTrencher IV Mk9 (deep water)
  • AssoTrencher V Mk3 (shallow water)
  • Venom 3k-600T with Mattress Installation Frame
  • Richoula 
  • Atom ROV


Project Specifications

Lavrio – Syros, Nearshore Protection Work & Mattresses

Nexans Norway A/S
Cable Type:
Power 1x 150kV HVAC XLPE 3x 630mm² Cu
Cable Weight:
48 kg/m
Cable Diameter:
201 mm
Service Provided:
Cable Protection – Pre-lay Mattresses Installation - Landing Assistance
Trenching Length & Burial Depth:
3600m (Pre) & 5660m (Post) @ 0.5m, 1.0m, 1.6m or 2.0m
Jetting Length & Burial Depth:
2110m (Post) @ 1.0m & 2645m (Pre with eductor)
Alternative Protection:
Pre-lay mattresses: 85m, Cement bags installation: 60m
Lavrio – Syros (Greece)
Max Water Depth:
120m (@ Jointing area)