Hull and deck
As in most other areas, we will also be breaking new ground in the manufacture of Zoe and our other ships and boats. Their hulls and decks, masts and interior fittings consist mainly from a wood-epoxy composite made from the finest woods, bio-based resins and, where appropriate, such as on the underwater hull, are reinforced with high-performance fibres like aramids (Kevlar), using state-of-the-art laser-assisted CNC manufacturing technology.
The path to a ready-to-install component thus involves the difficult choice of the type of wood with the optimal physical properties for the respective application, from certified sustainable sources. For wood from international (overseas) sources, the next step is to find a suitable local sawmill that is capable of sawing the raw logs in a radial cut (quarter cut) and, if necessary, pre-drying them. Then a suitable means of transport with the smallest possible ecological footprint to our timber warehouse has to be found. Timber from European sources is usually delivered as raw logs and processed at our own sawmill. The quarter-sawn logs are then gradually sawn further to the dimensions required for the laminate and dried.
The next stage is to laminate the components and the wood, which now has the desired residual moisture content, is precisely cut to the final dimensions of the individual laminate layers, planed and finger-jointed at the longitudinal joints and, if possible, without delay (to avoid dimensional changes due to shrinkage and swelling of the untreated wood) glued and coated with epoxy resin in the respective moulds. The laminated raw part is slightly oversized in order to compensate for the inevitable – ideally minimal – changes in shape caused by restoring moments and internal stresses in the individual layers, which are now firmly bonded together, after removal from the original mould.
It is then sent for final processing to a high-precision CNC machining centre, where it is milled into the desired three-dimensional special shapes that cannot be produced as laminate and provided with drill holes, finger joints, connections and much more. Immediately afterwards, the entire surface of the component is coated with resin again and – as between the individual steps – measured by laser and logged for quality assurance. The resulting component with clearly defined physical properties is absolutely dimensionally stable, with manufacturing tolerances typically of two tenths of a millimetre, and can be easily stored and transported until final installation at the Public Building Show, where the individual, precisely matching components are assembled like Lego bricks, so to speak.
After that, she can be launched, either by slipway or crane, and completed at her berth. At the same time, work on the next hull begins on land.
The further work stages of construction at a glance:
• Interior
• Technical installations
• Engines and batteries
• Rigging
• Commissioning
Examples of building materials to be used and comments for further discussion
Outermost layer:
- Chlorocardium rodiei (Greenh(e)art) DNV ice skin recommendation (ecologically acceptable sources ??), difficult processing
Robinia pseudoacacia? (good sources for long straight logs from Hungary), advanced processing - Castanea sativa (Sweet Chestnut)?
Layers of aramid fibers? (UV-sensitivity! salt-sensitivity! moisture absorption!)
Inner layers:
- Picea abies (European spruce)/ Abies alba (Fir), (excellent mass/strength ratio, insulation, easy processing, cost-effective, unlimited availability at the workshop site in Austria),
- Larix decidua ( better durability, hardness, good processing, unlimited availability at the workshop site in Austria)
Innermost layer:
- Inner layer may be sealed with hard oil (e.g. linseed oil varnish) or similar and only glued with epoxy at the joints.
Epoxy:
biobased epoxy resin
Health risks (link wikipedia): https://en.wikipedia.org/wiki/Epoxy#Health_risks
Double hull:
Possibility of a sandwich construction with PE middle layers? (unsinkability, ice class, thermal insulation,…)
Examples of cold moulded vessels of other boat and ship builders:
More about cold moulded wood construction: