‘CAD modelling has been a saviour,’ believes Izzy Pritchard, Twizzle’s ETO. The Computer Aided Design software used in conjunction with Rhino and Shipconstructor programs creates 2D and 3D design and drafting images and has become an essential tool in the development and design of Twizzle.
AutoCAD was applied to every area of the boat ensuring that space in each zone was completely optimised, making certain, for example, that all the equipment fitted without pinch points for the crew and without door opening restrictions in the confined areas of the engine room. At the hull construction stage, sheets of Alustar hi-tensile aluminium would arrive at Royal Huisman and through AutoCAD, precise cutting, shaping and cataloguing was possible. ‘It saves walking onto the boat, taking a measurement and then going back to the workshop,’ says Pritchard.
‘Some of the cavities in the boat run air ducting, electronics, fire fighting equipment and all types of services and you just wonder how on earth they got it all to fit.’ Val Zahov, one of Twizzle’s Chief Engineers involved with the build, agrees: ‘This is probably one of the strongest and most important skills. To get everything to fit and utilise the space to the maximum is something that no one can do as well as Huisman.’ He goes on to explain: ‘There isn’t a single air-gap on Twizzle unless it is dedicated to storage.’
This achievement is doubly impressive on a sailing yacht: ‘Considering the shape of the hull, I’m amazed at how much space we have on the boat,’ he continues. ‘Those motor yacht builders….they don’t know how easy they have it!’ Arjo Spans from Royal Huisman concurs with the yacht’s engineers. ‘If you look at the size of the hull and the scale of the interior, every bit of space has been used to make the interior as spacious as possible,’ he explains. ‘This can put a major pressure on the engineering department as their space gets really limited. All the wiring and plumbing has to run through these spaces and using 3D drawings and computer programs combined with expertise allows us to build a boat of such complexity.’
The most mechanically complex external area on Twizzle is the stern platform. Rather than a relatively simple platform that folds out on hinges to form a teak-clad bathing area, the transom slides down and then opens revealing the stern swim platform. Royal Huisman’s system comprises two separate sections that can be raised or lowered above sea level depending on the sea state and linked by adjustable, teak steps. The upper steps from the main deck can be opened hydraulically to access a storage area for scuba diving gear, a sailing dinghy and a pair of kayaks, with a carbon fibre swim ladder can be deployed from the lower section of the platform.
With the complicated manoeuvre and multiple functions of the stern platform, the System Integration Department at Royal Huisman devised a program to operate the entire sequence of movements from initial deployment to flushing the swimming ladder with fresh water after use. Impressively, not a single hydraulic ram, cable or catch is visible and the entire structure is capable of mooring a tender despite the lack of a supporting hinge above the waterline.