It is a logical step in the world of racing Trimarans to “teach them in foiling”… as we have seen the success and competitiveness of foiling catamarans these days (we remember the G4 Gunboat in spring 2015 at the speed record of 31.9 knots).
If the enthusiasts for Trimarans want keep alive the image and reputation of these 3-hull boats as the fastest boats under sails on our planet, it must happen as logical step to bring out the leeward floater (ama) for less drag and new potentials of higher speed. I have the confidence, that foiling trimarans will increase by speed a plus of 10% and we soon will see boats (over next 1-2 years) coming into the range of 40-45 knots.
Realistically it will become a tricky challenge for naval designers, boat builders and superior material developers same as for sailing crews to handle Tris using parallel (central) daggerboard, profiled foils, T-rudders and cantable rotating wing masts.
It’s fragil experimenting for keeping the balance on board of such a speedy boat and to avoid heavily bow pitching with the risk of capsizing. It seems the Gitana Racing Team is doing a great job these days in their laboratory we now get the first images in the world of sailing documenting a foiling 70 Foot Trimaran, the Gitana XV. – Congrats ! I really love what I see (click on the video in the news).
It’s very close to the end of July and I just received following news from the media center of Gitana Team around skipper and key figure Sébastien Josse. We get a first idea about what happens currently on board of Gitana XV (Multi70 Trimaran Edmond de Rothschild)…
Multi70 Edmond de Rothschild, time for the initial reports
30.07.2015 – 01:55 pm CET
Whilst those taking their summer breaks in July and August prepare to cross paths on the holiday trail, the members of Gitana Team are continuing to busy themselves with the final stages in the construction of the Mono60 Edmond de Rothschild. Indeed, the launch of this new craft is scheduled between 6 and 10 August in front of the Multiplast yard in Vannes, south-west Brittany. In the run-up to this major event and the subsequent breaking-in period with the new steed, Sébastien Josse certainly has plenty to keep him busy. Along with maintaining a solid fitness regime with a view to his participation in the Transat Jacques Vabre, the skipper of Gitana is continuing on with a series of test phases aboard the Multi70 fitted out by Baron Benjamin de Rothschild, which has been transformed into a genuine test laboratory.
First flights offshore
The first images of the Multi70 Edmond de Rothschild taking flight offshore of Belle-Ile-en-Mer are indicative of how much ground has been covered by the Gitana Team since the start of the project to modify the 70-foot trimaran. For the record, at the end of 2013, the members of Gitana set themselves a bold challenge with a view to the Route du Rhum 2014. To give Sébastien Josse the chance to compete with the giants of the Ultime class, the decision was taken to replace the trimaran’s rudders and floats with T-foil rudders, appendages which have become a familiar sight on inshore craft since the 34th America’s Cup, but are still rather unique for an oceanic multihull. The outstanding 3rd place posted by Gitana XV at the finish in Pointe-à-Pitre convinced the team to move forward with phase 2 of the plan concocted by naval architect Guillaume Verdier, the engineers from Team New Zealand and the Gitana design office. On 22 April, after a few months tucked up in the team’s technical base in Lorient, the five-arrow racing stable unveiled the 2015 version of the Multi70 Edmond de Rothschild and her future sailing programme. Three months on, boosted by a series of varied sea trials, Sébastien Josse presents his initial report: “To date, we’ve been pleased with how the boat behaves but we’re not yet satisfied by the peak speeds attained. As such, we’ll continue with the test process until such time as we’ve reached all the goals we’ve set ourselves. However, the sea trials off Lorient haven’t been a complete waste of time, far from it in fact because they’ve taught us a great deal,” admitted the skipper of Edmond de Rothschild, before listing the positive points of this second test phase: “During the winter refit, we revised the T-foil rudders that I used to compete in the Route du Rhum. Modifications made to the blades of these profiles led to some symmetry issues, the direct result of which was a tendency to ‘cavitate’ in excess of 35 knots (Rec.: See video at bottom about cavitation problems). Basically, an air bubble formed on the profile making it unusable. We identified this flaw on our initial sea trials, and that was what was happening in the Tour de Belle-Ile, but the team has since revised this element and everything’s back on track. That’s one of the successes of our second phase of development. On top of that, the sea trials have given us a chance to check our theoretical data relating to the different behaviour of the boat according to either an L-foil or a C-foil. For the time being, we’re keen to continue our investigations along the L-foil route. The appendage currently fitted to the port float will be revised this autumn so we can quickly switch up to a V2.”
(Rec.: If you cannot watch the video directly here, pls visit the Media Archive of Gitana Team.)
On 11 May 2015, the director of Gitana, Cyril Dardashti, announced the construction of a maxi-multihull. At that point, observers had a better understanding of the team’s logic over recent months, namely a systematic ramping-up of their activities. Indeed, the series of tests carried out on the 70-foot trimaran have enabled Gitana’s architects and design team to operate on a large scale so as to validate the appendages and systems they wish to install on Gitana’s future maxi-multihull. It’s a ‘luxury’ that’s sufficiently rare to be worth highlighting, as Sébastien Josse points out: “practice is still a lot more worthwhile than theory per se and we’re incredibly lucky to be able to carry out our tests on what is almost a 1:1 scale. Not only does it enable us to save a precious amount of time with the development of Gitana’s maxi-multihull project, but it will also be an appreciable asset during the fine-tuning of this new giant. The boat’s line drawings are currently being finalised, but we still have time to pin down our choices with regards the appendages. Indeed, it’s worth pointing out that the first line of the specifications stipulates the design of a versatile maxi-multihull capable of both sailing and flying when conditions and points of sail allow.” The actual build of this new craft will commence in October 2015 with a scheduled delivery in the spring of 2017.
Cavitation problems on foils (experiment at the Cavitation Laboratory of Marintek, Trondheim / Norway.)