Submarine maintenance

Submarine maintenance covers the five lines that cross the Strait of Sicily and the Strait of Messina, which have an overall length of approximately 750 kilometres. Routine inspections are planned to keep the external conditions of the pipelines under constant control and to anticipate any maintenance work required, and to stabilise the pipelines on the sea floor.

External checks are divided mainly into two groups, depending on the type of survey and the type of vessel used (surface or submarine): inspections near coastal landing sites and inspections in the open sea. In addition routine aerophotogrammetric inspections of the coastal landing sites are carried out and over time automatic systems have been put in place for underwater repairs as part of emergency interventions.

For submarine inspections, crewed submersibles have gradually been phased out and replaced by an intensive use of R.O.V. (Remote Operated Vehicle) submarines, wireguided by a surface ship. The ship provides logistics support to the wireguided submarine vehicles, provides management and maintenance facilities on board, and offers a secure base for data acquisition and processing. The ships used for this form of inspection activity are comparable to oceanographic vessels for scientific research and are equipped with Differential Global Positioning Systems (D.G.P.S.), an instrument that enables the ship to find its position with unprecedented accuracy through the use of satellites.