Most developments in yachting are evolution, not revolution but every once in a while a boat is launched that’s a complete game changer, difficult to categorise because it’s distinctly different from anything that’s come before. Thus it is with Baltic Yachts’ 111ft (34m) foil assisted superyacht Raven.
This isn’t a raceboat but it is focused on taking performance to a whole new level. It’s not a blue water cruiser but it is designed to make high-speed, long-distance offshore passages, potentially crossing an ocean with the owner and guests on board. At the time of writing there’s nothing else quite like Raven afloat.
Even for Baltic, which has a long history of innovation, you have to go back 21 years to find a project that pushes the boundaries of technology as much as Raven. That was the Baltic 147 Visione, the first superyacht capable of planing at 30 knots. Packed with unique innovations and developed in house at Baltic with almost literally no expense spared, Visione is still a force to be reckoned with on the regatta circuit. The owner’s rep on the Raven project, Garth Brewer of A2B Marine Projects, has also been involved with Visione ever since her inception.
Raven is an equally bold step forward into the unknown. This is a development project rather than a typical custom build and it may take some time for the yacht to reach its full potential. The owner’s team and the yard are quite sensibly unwilling at this stage to make any claims or release any figures about performance. They have, however, shared some key specifications with Seahorse and those numbers make interesting reading.
Raven’s light ship displacement is 55 tons, with 9,300kg of ballast. The design waterline (DWL) length of 33.1m is just 90cm shy of the 34m overall length (LOA). Comparing those figures with the recently launched Baltic 110 Zemi – a state-of-the art, high-performance superyacht with 95 tons of displacement, 30 per cent ballast ratio, 33.5m LOA and 31.2m DWL – it’s clear that Raven is a very different beast.
Only their beam is similar: Zemi’s 7.6m to Raven’s 7.4m. Design and styling are by the Finnish designer and naval architect Jarkko Jämsén, who worked closely with the owner to define and refine the concept.
While Jämsén is primarily renowned for designing powerboats and large motor yachts, the key players in the technical design team, Botín Partners and Pure Design & Engineering, both have deep experience at the forefront of current grand prix ocean racing and America’s Cup development.
An almost full-scale mock-up of the entire boat was constructed and comprehensively checked before the build commenced. ‘In the early stages of the project we also built construction mock-ups in many different shapes to ensure that all bonding would be 100 per cent and followed up with NDT scans,’ Baltic Yachts’ project coordinator Mattias Svenlin explains. ‘That’s the only way to do it. Every square centimetre of the hull has been NDTed.’
Like an AC75 or Ultim trimaran, Raven’s hull and deck are intermediate modulus (IM) prepreg carbon laminates with Kevlar Nomex honeycomb core throughout, cured in three stages under vacuum at 85°C. Most composite builds of this nature require teams of expert freelance boatbuilders to be assembled, but Baltic Yachts has all of the necessary expertise in house. Only the construction of foils and foil arms was outsourced to a specialist fabricator.
‘When you want absolutely the most lightweight construction you can’t think about biaxial fibres and rovings and so on,’ Svenlin explains. ‘You have to go for 200gsm unidirectional IM fibre, which is three times as labour intensive. And with the very best quality IM fibre you have to debulk every layer, or at least every second layer. By contrast, with a SPRINT setup you can do it every 10 layers and that’s it, you’re ready to cure. I won’t put any numbers on it but the difference in labour hours is huge.’
The thickness of the hull laminate varies enormously, from very thin in the topsides near the bow to a hundred times thicker or more around the foils. When both of those areas then have to be cured in the same oven ‘it gets pretty tricky,’ – according to Svenlin.
The structural bulkheads and load-bearing panels inside the hull are made with the same high-end composite materials, using a lamination press, and then CNC-milled for a precise fit. The hull moulds were built in carbon to reduce heat differences and thus distortion during the curing process. This produces a near perfect surface on the hull’s outer skin so there is virtually no need to use fairing compound and the paint coatings effectively do the job of filler. Using this construction technique in a superyacht is unprecedented, according to Baltic.
Raven isn’t a classed vessel but the hull is constructed in line with the parameters of DNV GL classification. ‘We got them involved at an early stage,’ Svenlin says. ‘There were some areas and some details that they were nervous about so we built full scale sections of the parts of the hull with the most difficult shapes just to confirm that everything is totally bonded and to have an understanding of more or less every single layer – how many layers you can have for each cure and so on. That was a really big part of the project in the beginning.’ A structural plan review has also been certified by World Sailing.
Weight control has of course been a key factor throughout every aspect of the project. ‘To build in the lightest way possible you need to have everyone involved from day one,’ Svenlin says. ‘From the day you start with the hull mould, you should already be taking into account how to avoid using any extra fillers on the hull. And to keep that red line through the whole project is absolutely the key. If you find enough ways to save a hundred grams per square metre by looking closely at every detail – including things which are already lightweight – you end up saving a lot of weight.’
Some of the production techniques that Baltic has developed specifically for Raven will now be used in future builds. ‘We have learned a lot from this project,’ Svenlin says. ‘For example in 3D printing. It’s a good way to make prototypes, next morning you have it and can test it. We even 3D print with titanium, the pop-up deck cleats are one example where we have saved a lot of weight.
‘Another technique we have developed is using projectors to see exactly how much overlap we should have on a bulkhead,’ he says. ‘This has raised the level of quality in the details of our structural bulkheads.’
Raven’s central passenger cockpit – nicknamed the bird’s nest – is also a significant innovation. ‘There is a lot of engineering in that,’ Baltic Yachts’ project manager for the build, Sam Evans, explains. ‘It’s driven from the designer’s idea not to hide anything, to show the structure and the installations. From the cockpit you can see the bulkheads, the systems and you get a lot of light inside the boat.’
The carbon structure of the bird’s nest takes all the loads so the acrylic panels can be very thin. ‘The glazing on this boat was a huge study in itself,’ Evans says. ‘Acrylic is where we ended up. We went down some much more technical avenues but for the weight and longevity we want, this is the best solution right now.’
For shelter there is a hard spray top, hinged at the midpoint of the cockpit. ‘When retracted it folds aft and is mirrored in the back of the cockpit, so it almost disappears with the canopy matching the mullions in the cockpit structure,’ Evans explains. ‘It’s light enough that two crew can deploy it with a halyard. The boom has to be out of the way so it does need some forethought but when going out sailing for the day you can easily rig it before you leave and pack it away when you’re finished.’
Raven’s sailing systems are fully hydraulic, driven by a diesel-electric serial hybrid setup with two 80kW gensets powering three electric motors. ‘The concept is that she’s not going to be serviced constantly and won’t have a shore team on board every day,’ Evans says. Compared with a grand prix foiling monohull racer, a much higher degree of self-sufficiency is required.
Raven’s ultra-lightweight interior is highly unusual. The designer Jarkko Jämsén has turned the need for extreme weight saving into an opportunity to showcase the yacht’s complex carbon construction and some of its sophisticated technical systems redefining luxury.
Much of the hull’s inner skin and the load-bearing internal structures are left exposed and uncoated show casing the skilled workmanship so often hidden away. All the usual sound insulation materials have been eliminated, which saves a lot of weight. Lightweight acoustic foam is applied to some bulkheads to slightly soften the noise of sailing at speed. Even the adhesive used to attach the foam was subject to a weight study, saving 6kg.
Carbon tubes and rattan are used extensively in the headlining, panelling and furniture. Every carbon pipe bracket is 100g lighter than normal, using carbon cable trays reduces weight further and steel hydraulic pipework has been replaced with lightweight hosing, saving 160kg.
There is a large saloon with a dining area and galley just forward of the ‘bird’s nest’ passenger cockpit, two cabins for four guests further forward and crew accommodation up front, including a captain’s cabin. The aft part of the yacht is mostly empty except for the owner’s sleeping quarters, where a big double berth on the centreline folds up against a bulkhead and there’s a passage berth to starboard.
The guest heads and shower compartments are a highlight of Raven’s interior. Perspex panels give views of the complex construction of the A-frame that takes the load of the deck-stepped mast and the hydraulic rams that drive some of the yacht’s key sailing systems. While having a shower, the guests can see the upper and lower deflector rams in action or watch the downhaul ram for the 7m long reaching strut as it changes the headsail sheet leads.
The weight of the shower doors has been reduced from a typical 13.5kg/m² to just 2.3kg/m² and further weight saving has been achieved with carbon shower seats that looks just like bamboo, complete with characteristic rings and a realistic painted finish.
The full-beam mainsheet traveller is a crucial piece of kit on a boat like this. The rig itself is relatively conventional
Initially at least, all sailing systems will be manually controlled.
‘There will be a lot of further development and potentially automation,’ Evans says. ‘That is being prepared for but it’s seen as further down the line.’
To begin with, in foil-assisted mode the boat’s fore-and-aft trim will be controlled by a pair of interceptor trim tabs that move independently up and down like a planing powerboat.
‘Regarding rudder elevators it would be fair to say that considering the developmental nature of the project all options will be considered once enough data has been collected,’ Evans says.
The sailing team, managed by Klabbe Nylöf, will have a core crew of five including skipper Damien Durchon, who has prior offshore experience. A shore-based technical team will develop the yacht continuously to achieve its full potential. For the training and test phase of Raven’s development, additional crew will be drawn on rotation from a team of 20 sailors with solid high-performance experience.
So, what happens next? The commissioning process is expected to continue in Jakobstad for the rest of the 2023 sailing season. Then Raven will sail south on her own keel for the winter – and the innovation is set to continue.