Partager cette nouvelle

    * champs requis


    TF35 Ylliam XII - Comptoir Immobilier

    Background and general presentation

    Flying the TF35

    The first TF35 championship races have been postponed until the autumn due to the pandemic. These latest generation flying yachts succeed the Décisions 35, which occupied the forefront of the Lake Geneva scene for 16 years.


    Eight crews will compete from this autumn on the new flagship series on Lake Geneva, the TF 35. This latest generation catamaran, capable of flying – more precisely, of being lifted on T-shaped bearing planes – as soon as the wind blows at 6 knots (11km/h) should not fail to appeal to all sailing fans.

    More than twenty months of development were required to design this new planned craft, despite its high degree of technology. This is in order to be accessible to non-professional helmsmen.

    The boat is in fact equipped with an electronic flight assistance system that manages stability in height and on the longitudinal axis. Moreover, this system is not an autopilot, but an assistance that allows the helmsman to concentrate on the essentials, without having to worry about complex flight parameters.


    Reminder of the fundamentals

    Foiling, or sailboat flying, is a design evolution, which allows boats to move out of the “archimedean” mode. This mode means that the craft is doomed to push a mass of water equal to its weight. By flying, boats break free from this physical principle and can reach very high speeds, probably around 35-40 knots (approx. 70km/h), for a TF35.

    Foils are submerged appendages with wing profiles that function as load-bearing planes. They can be L-, V-, J-, or T-shaped. The F50s, catamarans in the prestigious Sail GP circuit are L-shaped, those of the GC32s J-shaped.These design choices depend on the boat’s specifications, the conditions in which it must be able to fly. They also depend on the performance required. The challenge of foiling is to allow a boat to take off as fast as possible so that it can accelerate out of the water. This is done by minimizing the drag from the appendages.

    In short, engineers need to find the right compromise of foil area. These must be adapted to the needs of average sailing conditions. Moreover, if we recall the principle that: lift increases as the square of speed, we can better understand the difficulty of designing a boat that can on the one hand take off with little wind, and on the other hand sail very fast when conditions strengthen.


    High-end design team

    Bertrand Favre, Master series of the Decisions 35 for sixteen years, and new Master series of the TF35, has put together a renowned and successful team to develop this boat. This one is composed of:

    • Spaniard Gonzalo Redondo, head of the Design Team, a renowned architect and involved in most of the big sailing projects of the moment.
    • The American-Dutchman Dirk Kramers, notably responsible for Alinghi’s victory in 2007, was in charge of structural issues.
    • The Vaudois Luc Dubois, a key engineer in performance sailing for several decades, was meanwhile responsible for the electronic flight control tools.
    • Marc Menec, a French engineer was in charge of the 3D modeling, while British aeronautical engineer Adam May completed the Desing Team.
    • The Vaudois Jean-Marie Fragnière finally coordinated all the trades involved in this project so that the TF35 could be made and developed in time.



    Ylliam XII-Comptoir Immobilier

    Bertrand Demole has been in the Decision 35 series since 2015 with Ylliam-Comptoir Immobilier. He finished the annual championship in second place in 2017, 2018 and 2019. The team also won the mythical Bol d’Or Mirabaud in the D35 class in the 2019 edition. Bertrand Demole and his men have become one of the best teams on the circuit in just a few seasons. Moreover it’s the reason that motivated the owner to continue in TF35 to continue this promising momentum.

    All crews who acquired a TF35 were able to train for a few days on the lake, aboard boat #0 launched in September 2019. This avoided inequalities in the number of days sailing before the regattas started.

    The next one is the TF35.

    This was then transported to Spain, to Mar Menor, in the region of Murcia, to continue its development, and to offer optimal conditions for the crews to carry out winter training. Bertrand Demole’s team was on site for five days at the end of February, and had ideal conditions to get to grips with the boat.

    “The stretch of water is very protected, and we had winds of 8 to 10 knots, so conditions quite similar to those on the lake,” said Thierry Briend, mainsail trimmer. He continued: “We took advantage of these outings to rediscover the boat after our first trials on Lake Geneva, and to assess the work we still need to do to tackle the first races in the best possible conditions. We will first of all rework all the manoeuvres, in order to pass them with ease, and then concentrate on the performance. The second part is going to be a long-term job, and will evolve as soon as we can resume our training. “


    Redefined schedule for TF35

    Of course, the constraints linked to the arrival of the COVID-19 have completely turned the schedule upside down. The boat that was supposed to be delivered in Brittany, assembled a first time, and then delivered in Switzerland in mid-April will not be delivered until early June. Once again, the impossibility to travel for the foreign crew has put everything in question. The first regattas that were to be sailed at the end of May have of course been cancelled, and the championship could start this autumn in Geneva.

    At this stage, and if the deconfliction continues, it is plausible to expect to have the full fleet during June. Of course, the schedule will be redefined as restrictions change. For example, an event planned in Nyon in July could be transformed into a joint training session. Similarly, the launch of the championship should take place in September at the SNG. The number of matches will obviously be restricted, and will be limited to two or three for this first season.


    The TF35 in a nutshell



    • Overall length: 15m
    • Hull length (excluding appendages and bowsprit): 10.85m
    • Overall width: 9.2m
    • Boat width (without ladders): 6.3m
    • Weight: 1200 kg
    • Crew weight (6 people): 500 kg
    • Draft: 2.45m
    • Width of foils: 2.7m


    • Enable non-professional owners to access a high-performance foiling catamaran.
    • To have an automatic flight assistance system.
    • Both the foils and the T-shaped rudder are equipped with flaps.
    • The TF35 is designed to sail both on lakes and at sea.

    • The TF35 is (relatively) easily transportable (2-piece mast, fits in a standard 40-foot container).
    • Can be packaged for transport then assembled in one or two days.



    Owner and helmsman: Bertrand Demole (SUI)

    Tactician: Erwan Israël (FRA)

    Mainsail : Thierry Briend (FRA)

    Mainsail car : Pierre Pennec (FRA)

    Forward crew: Alexis Rochat (SUI)

    Foresail trimmer: Teva Plichart (THA)

    Reserve Crewman: Florian Trub (SUI)



    Top of the page