Flat Ribs From Green Wood
Rib gathering in urban environments
Making flat ribs from green wood
After you have collected your rib stock, you can store it for a week or two in a cool place without losing too much moisture. In general, you want to process your cut lumber as soon as possible. Otherwise you lose the benefit of its high moisture content.Once you are ready to make ribs, you need to cut your stock to the length of your longest ribs and split it into sections suitiable for shaping.
In this picture, I am splitting a piece of elm using an adze. You can also do this with an axe or hatchet or a froe, a tool made especially for splitting wood.
The picture on the left shows a section of elm split in half. The picture on the right shows the two pieces split again into quarters.
How often you split a piece of wood depends on how big it was to start with and how well you can control the splits. Some wood like elm does not split well at all in larger diameters. Time to experiment. Also, since splits follow the grain of the wood, you are much less likely to have grain runout than with sawn lumber. Hence you can go ahead and make rib stock with flat grain.
After splitting, the shaping starts. In this case, I am removing bark with an adze.
Rough shaping with the adze is followed by fine shaping with a plane. Green wood planes much more easily than dry wood. Nevertheless, there is a little more labor here than in simply running flat boards through a table saw. Also, when you're done, you will have a big pile of shavings at your feet.
Yields for flat ribs may seem disappointing until you realize that this is the nature of the practice. By the time you split a section of tree, remove the bark and shave it down to the proper dimensions, you may have turned one third or more of the stock into shavings. Luckily, green wood shaves easily and shaping it is a pleasurable activity.
Once you have reduced your stock to proper rib dimensions you may still end up breaking it. But as with round stock, once you learn to spot defects that disqualify a rib, you can abandon bad stock early in the process and not even bother shaving it down.
Ribbing the boat
Once you have your rib making process down, try to rib as much of the hull in a single run as you can. Green ribs shrink as they dry and if you wait a whole week between ribbing sessions, your ribs in place will have shrunk and you will be trying to match up your new as yet unshrunken ribs with the ones that have already shrunk and try to guess how much larger they will have to be to account for shrinkage.
Once shaping is complete, we run boiling water over the rib to soften it up for bending. Steaming the rib is also an option as is putting it in a trough of boiling water.
When the rib is hot enough, we bend it. In this case, I am putting a sharp bend at the edge of the rib.
This rib has some irregularities in it, but they are small and don't fall on the bend so their impact on the rib is minimal.