Building the cutting edge sailing yacht Athos
by Andrew Rogers
With 300kW on the thrusters alone, and taking into account efficiency losses and the hydraulically powered controllable pitch propellers, Athos now had a simultaneous hydraulic power factor in the range of 450kW.
‘By this time, we had prepared a hull construction and layout for a system one fifth of the size so we had to rethink the proposed design, working everything around the entire installation to keep it all concealed,’ says Zijlmans. ‘The pumps on the main engines and generators are huge and the piping needed to transfer and hold the pressure involved in such a vast system power is tremendous.’
Some 80mm in circumference, the pipes and their brackets had to be installed in a way that would be both resilient and sound insulating. While such heavy duty gear may be common in the commercial shipping sector, the restrictions on a luxury yacht where real estate is so precious – and peace and quiet so valued – made this a colossal challenge.
A similar dichotomy between two different maritime worlds can be seen in another of the owner’s innovations, which had been a key feature of the original specification.
Athos has double redundancy of almost every system on the boat, divided into port and starboard systems. Twin main engines drive two propellers, while two 90kW diesel gensets and two shaft generators provide a parallel power supply (add in the emergency generator aft and you have five gensets on a sail yacht). The shaft generators are another relatively common feature in the shipping world that you will not find on many superyachts.
The owner’s requirement for Athos to have dynamic positioning (DP) is also very unusual.
‘As far as we know, this is a first on a sail yacht so we had no reference point,’ says Zijlmans. ‘It is not the DP system itself that is complex, it’s the communication of the signals within the system and how parts of the yacht respond that are the big deal. The installation itself is driven by GPS signals, but the desire to have it hydraulically operated was something altogether new.
‘Finding a solution entailed a great deal of discussion with the yard, the DP installation manufacturer, the hydraulic components and engine controls suppliers, and the naval architects. In addition to being able to enjoy quiet without anchoring up, a secondary benefit is that it will be possible to manoeuvre Athos using a “simple” joystick.’