Winds and rough seas affect the land extension

Particularly unsettled weather in October and early November has disrupted the progress of work on Monaco’s Portier Cove land extension project. There has been slight damage and delays but the overall schedule will not be affected.

High winds and a southerly swell of historic intensity have hindered the work of the teams working on the Portier Cove land extension project over the past few weeks. Part of an outfall being installed broke away and came ashore on Larvotto beach, the needle on the vibro compaction barge broke, a shutter smashed and the installation of a caisson was delayed.

“The third caisson, which is known as C1, arrived from Marseille on 30 October as planned.” says Christophe Hirsinger, Director of Bouygues TP Monaco. “But we had to keep it at its mooring place for several weeks due to the meteorological conditions.”

Yet Christophe Hirsinger does not seem overly concerned.

“We planned to complete the installation of the 18 caissons by the end of May and we will be on schedule,” he says. “We are still pursuing our objectives to install six of them before the end of the year [2018].”

Naturally, meteorological events such as these were factored into the plans for the site, which will be open for almost five years and therefore, for five winters.

“We also suffered damage to a shutter on one of the caissons,” says Christophe Hirsinger. The caissons are perforated and plates block the various “windows” so the caisson can remain watertight while it is being transported to its final installation, following ballasting with solid materials. One of these shutters gave way and needed to be repaired before operations could continue.


The part of the outfall that came ashore on Larvotto beach has been removed. For safety reasons, it will be replaced but with not cause any delay: its installation is scheduled for February, according to the initial calendar. Finally, the vibro compaction needle that broke on 12 November will no longer disrupt plans.

“We know that with such a long-term site, more or less violent meteorological events can be envisaged, without taking into account the various other reasons that might lead to certain parts breaking,” says Christophe Hirsinger.  

“That’s why it’s necessary to plan for replacement parts. We had a replacement needle. We were also able to react very quickly, and the needle was replaced the following day. At the same time, a new extra one was en route.”


So, the Director of Bouygues TP Monaco is still smiling. Despite the rough seas, most of the operations stayed on track. Above all, although the high seas of 29 October were exceptionally violent, the two first caissons that had already been installed resisted the assaults from the sea perfectly well, even though they were not yet attached to the entire ring. This validates the methods and protocols that have been devised.


In Marseille, work is continuing at the pace planned in the provisional schedule. Construction of the last caisson is underway and should be finished before the end of the month. In Toulon, France and Piombino, Italy, the loading of the ballast material is continuing without any notable issues. In Imperia, also in Italy, the rocks removed in the earlier phases of the offshore extension works are being recalibrated before being taken back to Monaco.

This is based on an article by Georges-Olivier Kalifa, published on 28 December 2018 in the Gazette de Monaco