Ordering the timber
The restoration starts with ordering the timber. There are a number of specialist timber merchants in the Netherlands who are able to supply timber planks of sufficient length.
The timber that you want to order must first and foremost be of excellent quality; cabinet-making quality is not necessary but the timber must be healthy, there must be no rot (watch out for brown patches on the cross end!) and there must be not too many knots. Secondly, you have to order sufficient timber, but not too much. Normally you order one or more trees that are sawn into the planks of the required thickness by the sawmill. You of course order the type of timber that you need; this can vary for each type of boat. The mussel boat ‘Nieuwe Zorg’ is built from oak, therefore a number of cubic metres of oak was ordered.
Before you can order the timber you first of all calculate the volume of timber and the thicknesses you require on the basis of the lines plan, the design of the hull and frames and the boat construction drawing (image 1). You proceed as follows:
- For the boat skin and the deck straight planks from the trunk are used for this type of boat. Determine the width and the thickness of the planks you require.
- For the frames you use thick planks, which in the timber trade are known as "timber slabs". To order the correct timber for this you first look at the run of the grain and the structure of the timber. The timber has to ‘follow’ in order to obtain sufficient strength. On the basis of the design of the hull and the frames determine the amount of timber slabs you need. Remember that there will be a lot of loss when sawing out the frames from the timber slabs. Take into account the following considerations when calculating the volume of timber required:
- For a frame of 10.5 cm for example, you first rough-saw a thick plank to 12 cm. You then undertake additional work on this. Using the current method you will end up with more waste timber than previously, sometimes even up to 70%. The main reason for this is because we now obtain timber for curves from very thick planks in a less efficient way, rather than use timber from tree crowns.
- In the past, boat builders often used timber from the crown of a tree in order to make frames. The crown often contains timber at 45 degrees, which were ideal for making curved members. Furthermore, that curved timber was not particularly suited for other uses.
- Make templates of the frames in advance and take them to the timber merchant, so that you order sufficient timber and timber with the correct curvature. Take into account an oversize of at least 2 cm. The frames have more bevel on the front and back, for which you therefore require more material.
- Sapwood must not be used and has to be cut away. Sapwood is not strong enough and attracts fungi and rots quickly. It can also affect the good timber. Therefore, choose timber with the least sapwood possible. (If the grain of a piece of timber runs well and there is a small piece of sapwood that will not be on the skin side but will be on the inside then you can cut that away using a chisel or adze and still be able to use the timber.)
- Ask the timber merchant to attach end strips to the cross-cut ends of the planks in order to prevent the planks from splitting.
Wooden hull: frames and strakes