manoeuvrability.” Feadship introduced a podded azimuthing propeller. “This electri- cally driven, contra-rotating propeller can spread the load better and it has 360 degree manoeuvrability. It has good inflow and higher fuel efficiency.” The new concept design also had a medium speed diesel engine rather than a high-speed engine and two large rudders. Feadship was expecting fuel savings of 20-30%.


Following a concept desk study done with MARIN on the merit of such a propulsion system and possible alternatives, a model testing programme was undertaken to confirm the expectations. “The propulsion method is


very innovative, we were confident it would work but were concerned that maybe we couldn’t achieve the levels of efficiency we thought were possible. We also had con- cerns about the manoeuvring and steering, given that the boat would have one propeller with a pod behind. We had to prove it and keep our promise to our clients. “We wanted to show them what could be achieved in terms of efficiency and sea- keeping. We were delighted that we did achieve the numbers and even better then we had originally thought!”


And this undoubtedly impressed the client as the first concept turns into reality. The


Feadship’s superyachts are world-renowned and MARIN is often at the start of the process - when pioneering concepts are turned into reality


first yacht with this new hybrid system is underway. The hull arrived at the yard in October and the yacht will be completed in 2015.


Although the client can’t be revealed, Mr Schouten says the owner was interested by the fuel savings, but more importantly, it was really about the flexibility of the system. “This yacht can sail diesel electric or diesel direct and is very manoeuvrable. And buying yachts of this type our clients are always supporting innovation. They are always pushing the boundaries, and what is learnt in this arena is also interesting for shipbuilding in general. “


The hybrid system will absolutely be chosen by other clients, he says, adding that even though it maybe a slightly higher investment in the first place, it will be earned back in a few years.


Another ground-breaking project MARIN has been involved in was for a certain aluminium yacht – the name cannot be revealed - with an all-glass superstructure. “This was a really revolutionary project. Essentially, aluminium deforms and glass doesn’t and could easily break. We had to combine simulations with a complex model testing programme in waves and measure the deformation of the model, which impor- tantly, had the same stiffness as the real yacht. This was the first time we had used that much glass - 10 m long panes – so it was very risky.” This amazing yacht has now been sailing for a year with no prob- lem at all. “The stresses correlated with the measurements better than we had dared to hope,” he points out.


Because there will be more yachts with an Axe Bow, Feadship has also been working with MARIN examining the seakeeping be- haviour of these yachts in stern quartering


Aluminium yacht with an all-glass superstructure report 7


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