Inside the AC75 Luna Rossa: the control systems on board


The AC75s, defined by one of the two design coordinators “one of the most complex boats ever launched,” imply the use of sophisticated management and control systems and a dense network of valves and pistons. We spoke with hydraulic specialist Massimiliano Carbone of the details of how this kind of boat works

When the first Luna Rossa was launched in Cagliari on October 2, 2019, we exchanged a few words with one of the two design coordinators, Dr. Martin Fisher: he explained that the AC75s were certainly the most complex boats ever launched, in particular for the highly sophisticated electronic systems that the rule does not allowed to “speak” to each other too much, to ensure that handling and in particular foiling being automatically controlled. “For example,” he said, “there are the flaps to control and is no room for electrohydraulic systems.”

At the end of the 36th America’s Cup, team Luna Rossa Prada Pirelli began to release a few more technical details, but without revealing too many of the secrets of these radical boats. We spoke with the hydraulic specialist, Massimiliano Carbone, during an encounter organised by Pirelli in the famous Portofino square on July 9.

Present were Team Principal Patrizio Bertelli and Pirelli CEO Marco Tronchetti Provera, together with representatives of the team including the skipper Max Sirena and Boat Captain Michele Cannoni.

The encounter organised by Pirelli in the Portofino piazza on July 9

A pearl of engineering, hydraulics and electronics

Sailing a boat like the AC75 requires the use of sophisticated management and control systems and a dense network of valves and pistons.

In each team there is a department dedicated to the study and development of these systems, the mechatronics department made up of mechanics, hydraulic, electronics, engineering and software experts: a group fully dedicated that works to produce and manage these very complex systems that make the whole boat work. Without them it would be practically impossible to handle an AC75.

This kind of boat is extremely complex both in engineering and handling terms. It is a boat of about 7 tonnes that, with 12 kn of wind, reaches speeds of more than 40 kn, without the hull touching the water but balancing on a blade of a few sq.m. A magic of engineering, but also a complex hydraulic and electronic system.

Michele Crotti, mechatronic engineer who handles analysis, architecture and software development and mechatronic system

How it works in detail

The subject of the interview, Massimiliano Carbone, specialised in on-board hydraulic systems

“The systems on board and the automation of the boat,” says Massimiliano Carbone, “are completely hydraulic. Inside the hull there is a sophisticated system of pistons to which are connected lines for various manoeuvres, the outhaul or the jib cunningham or the movement of these pistons, which is created by pumping oil into the system and makes it possible to trim or ease a sail. The oil, which runs in a hydraulic network and powers the pistons in the hull, is pumped by the grinders with four pedestals. By using the valves installed on board, the crew decide which pump should receive oil, according to the requirements of handling and manoeuvring.”

For example, a jibe involves a complex combination of buttons to open or close certain valves. “On-board there are various computers and one of them is dedicated to managing the hydraulic system through software that allows the crew to activate, using the buttons, the hydraulic valves that move the oil around.”

Revision and monitoring

From the helm it is possible to control the parameters of the AC75

Every day of sailing, before the boat leaves the base, there is a careful revision of the system by technicians, called the ‘Mecca System Check’.

“It is a very in-depth test of functions in all stations,” says Carbone. “All the keys on the displays and controllers are checked and we test that all buttons are working, that the valve opens correctly, that the cylinder is properly calibrated, measuring the/and the values at the end of stroke and release. When the mast is then stepped on the boat and the boat launched, there is the “system check” by the crew. Each of them checks their own station and that all functions are calibrated: nothing different from the sound check that musicians do before a concert.”

These systems are monitored while sailing and during the race. “The technicians and engineers following the AC75 chase boat,” he says, “and they monitor the values they get from the on-board systems on their own computers, a kind of Formula One pit wall. As the race unfolds they keep under control all the numbers arriving from the many sensors on board, including temperature and oil pressure, loads, performance and, if there are problems in the system, the lads in the shore team are ready to intervene between one race and another to fix them.”

As the race unfolds all the data arriving from the many sensors on board are kept under control
The main systems of the AC75: how to avoid a self-handling boat
There are four main systems governing the operation of an AC75:

  • the FCS (Foil Cant System), which handles the movement of the foil arms. It is one design, equal for all teams, and supplied by the Defender;
  • the ILS (Instrumentation and logging system), which manages the data coming from the instruments on board (compasses, GPS, measuring sensors etc);
  • the CIS (Crew Information System), interface between the boat and the crew;
  • the ECC (Electronic Control Circuits), which manages the boats hydraulic system.

By rule, these four systems must work separately and communicate among themselves only in preestablished ways, passing by the Media System supplied by the Defender, which allows the various systems to dialogue according to preestablished protocols.

For example, the ECC can send information to the ILS but not receive information from it. The prohibition of this feedback is to avoid a boat using self-governing systems, such as an automatic pilot automatic flap management.

In addition, the ECC and the ILS can send information to the crew only through the Media System, which adds a second’s delay to the information coming from the ILS. This means the data from the sensors installed on board are shown on crew displays with a second’s delay. This too avoids the computer substituting men in the handling of the boat and above all in the handling of foiling.

Umberto Molineris, grinder on Luna Rossa, who also manages certain systems