Nanni, the French marine engine manufacturer, has been granted "SEA Index Ally" status, joining a growing list of industry players signed up to an independent environmental rating system for superyachts.
The SEA Index was developed by the Yacht Club de Monaco alongside Credit Suisse. It rates the CO2 emissions of vessels over 24 metres using available technical data, giving owners, captains and shipyards a transparent benchmark for comparing environmental performance.
Bernard d'Alessandri, General Secretary of the Yacht Club de Monaco, said the addition of Nanni signalled a broader shift within the industry.
"Welcoming NANNI as a SEA Index Ally further reinforces our collective capacity to drive meaningful and lasting transformation within the yachting industry. Innovation is no longer confined to engine manufacturers. It is now reaching equipment specialists, including generator makers such as Nanni, which is a clear sign that sustainability is permeating every layer of the maritime supply chain."
Nanni's pitch rests on its Complete Marine Power Solutions package, covering hybrid propulsion, generator sets and its BESS battery systems. The company points to its Dual Fuel system, which runs on methanol and HVO to cut CO2 and NOx output, plus a "Soundless" cabin design claiming noise reduction of up to 10 decibels below market standards.
These technologies have already been tested in the Life Mystic project, a collaboration with Sanlorenzo and MAN aimed at meeting the IMO's 2050 greenhouse gas targets. The Sanlorenzo Almax 50 Steel, fitted with a methanol reformer developed through that project, earned a three-star SEA Index rating.
Gregorio Passani, Chief Business Officer and General Manager at Nanni, framed the partnership as a practical step rather than a marketing exercise.
"We believe that technological innovation must translate into measurable environmental progress, and the SEA Index provides the scientific and operational framework needed to make this transition real."
The announcement coincided with the 30th Captains' Forum in Monaco on 24 March 2026, where Nanni's Giammario Meloni, Commercial and Sales Director for Defense in the Mediterranean, took part in a panel on resilient yachting technology.
