West Africa - SahelBlog AnalysisInterview

Corymbe, a double-sided mission (Cap. Vessel Tranchant – PHA Tonnerre)

(B2) Before the summer break, I chose to give the floor to the commander of the amphibious helicopter carrier Tonnerre, Captain Arnaud Tranchant, who has just completed a presence in the Gulf of Guinea

The CV Tranchant on board the PHA Tonnerre (credit: French Navy)

Launched at the beginning of June, this mission is now a classic for the French navy. Since 1990, a building has been present in zone (1). This time, with slightly different execution conditions, taking into account the Covid-19 crisis.

Corymbe, is it a multi-faceted mission in fact?

— We can say that. Our presence has two parts. First, ensure the security of French strategic interests. We carry out patrols of the bottom of the Gulf of Guinea, in the area where our industrial operators are present, in interaction with the French forces prepositioned in Ivory Coast and Gabon. It is a purely national aspect. Secondly, we support the navies of the Gulf (Senegal, Ivory Coast, Benin, Togo, Nigeria and Gabon). We carry out joint patrols or carry out flights for their benefit with our on-board helicopter Caïman (2) to monitor the exclusive economic zone, or fight against piracy and illegal fishing. We do joint training and carry out multiple exchanges.

Is this collaboration an important point?

- Of course. This allows us to share our appreciation of the situation. Then the fact that the French navy is present regularly gives us credibility, allows us to forge fairly intimate fraternal links with these marines in such a way as to speak to us as true brothers in arms.

Has the Covid-19 crisis led to a change in the course of the mission?

- Indeed. This mission took place in unprecedented ways with six weeks at sea, almost autonomously. We made just two diesel refueling stops in Dakar. But without a supply of food or water [Le Tonnerre is equipped to produce its own drinking water]. It was demanding for the crews. But we managed to find ways to deal with the fatigue induced by these conditions.

This isn't the first time you've been in the zone. The seventh if I counted correctly. What lesson do you learn from this?

— This is my seventh mission in the Corymbe zone. There is density at sea here and a great diversity of actors. Between local fishermen, more offshore fishermen, often Asian, the presence of oil platforms, without forgetting security actors, private or state, we clearly see here the maritimization of the world. There are a lot of people on the water. In twenty years, I have been able to witness the densification of activities, with an evolution in security, linked to the increase in these activities, legal or illicit.

Are the local navies able to counter this threat?

— I will not pass judgment on the state of the marines. What I see is that they produce operational effects. They already have capabilities and are gaining strength. They navigate, patrol, intervene. In terms of information sharing, the [Yaoundé] process is having an effect. Now, maritime intervention remains a major challenge. There are still areas of effort.

Has the coronavirus crisis also changed the modes of action of pirates and sea bandits?

— The fall in oil prices has produced an evolution in the pirates' mode of action, as well as geographically. The diversion of oil (bunkering) becoming less profitable in the Gulf of Nigeria, they turned to hostage-taking, lucrative with the ransoms. THE bunkering were previously very concentrated in oil areas. But this hostage activity occurs outside of these areas, much further from the coast. Which increases the risk areas. We will have to watch in the future if this development persists.

These attacks remain rather violent, compared to what is happening in East Africa?

— The very violent nature of pirate acts in this area persists. That hasn't changed. They are not converted fishermen like in Somalia. Here, these are criminal organizations, organized for this objective, for which this is the main income, with an imperative for results. These are rapid attacks. They boarded very quickly, left with selected hostages also very quickly, to return to their hidden bases [from where they negotiated the payment of a ransom]. They are armed, with significant self-defense and aggression capabilities. This forces us to adapt our methods: the attack being rapid, we must act quickly.

Did you intervene?

— Whenever we could provide support, we did so. We were thus able to observe [remotely] three pirate attacks (3). All three resulted in hostage-taking. For two out of three, we were too far away to intervene. One was closer in range. We deployed our Caiman helicopter to enable tracking of all nearby vessels. The information was passed on to partner navies to enable them to act. We then approached the pirated ship, to comfort the sailors, see if there were any injured, and gather information. It's always useful to know how hackers operate.

After Corymbe, what is your program?

— Return to Toulon, where we will be on alert in mainland France. At the end of the year, the ship will experience a technical shutdown. And next year (2021), we will carry out the 'Joan of Arc' mission to train young officers...

(Comments collected by Nicolas Gros-Verheyde)

Interview conducted on July 11, 2020, by telephone while the PHA Tonnerre was in the Gulf of Guinea, in rather heavy seas. The ship returned to port on July 17.


The 'cooperation' aspect of the mission

The Corymbe mission began with joint training with the French elements in Senegal (EFS) and the Senegalese navy. At the end of June, he first trained with the Ivorian patrol boat L'Emergence the lagoon of Abidjan, then, in the Gulf of Biafra, with the Gabonese forces with, at the key, amphibious training, diving and anti-piracy exercise. The Cayman helicopter then patrolled at the request of Nigeria and Benin to spot ships. After a second logistical stopover in Dakar, on the way back, the Tonnerre conducted a situational awareness exercise “ surface » and a winch with the Senegalese patrol boat Fouladou. In total, more than 16.000 nautical miles traveled by the ship and 63 flight hours for the Cayman helicopter, including 12 maritime surveillance missions.


  1. France deploys at least once a year in the area a large amphibious ship or helicopter aircraft carrier (Tonnerre, Mistral, etc.).
  2. The use of the helicopter has a big advantage: increasing the length of the ship. The Caïman's fairly significant autonomy allows it to operate within a radius of approximately 100 nautical miles (with half an hour on site and the return trip). Above all, it is equipped with a surface surveillance radar. high performance » which allows the collection of images day and night.
  3. There is an alert triggering system, both on VHF and satellite radio (doubled on several frequencies). This allows both public ships to intervene and merchant ships to be informed and protect themselves from an attack. The global coordination centers are also informed (via satellite), allowing the information to be passed on to all other ships.

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Nicolas Gros Verheyde

Chief editor of the B2 site. Graduated in European law from the University of Paris I Pantheon Sorbonne and listener to the 65th session of the IHEDN (Institut des Hautes Etudes de la Défense Nationale. Journalist since 1989, founded B2 - Bruxelles2 in 2008. EU/NATO correspondent in Brussels for Sud-Ouest (previously West-France and France-Soir).