Last Saturday was a long day. Gerald was on site, his last day here for a few weeks. Linda got a lot of painting done, putting both beetle-proofing solution on timbers and painting others with a pine tar formula. Donal and I laid out and cut a floor timber. We were not very pleased with our results, as we had a hard time finding a good piece of wood that was wide enough to fit the curve we needed, even though it is one of the middle timbers and not one of the more extreme ones near the bow.
We are working with slabs of white oak that are four inches thick, two to three feet wide, and seven to ten feet long; heavy enough to need a forklift to horse them around. This makes even locating a good candidate slab in the stacks of lumber a drawn out process. Given that we have a limited amount of wood, we have to avoid being profligate with the lumber, and must try to find the smallest slabs that will meet our needs for a timber, leaving the best slabs for the more difficult bow timbers.
It was my first time using the beam cutter, which is the bastard offspring of a circular saw and a chainsaw. With a clever attachment called a Prazzi, you can replace the dangerous seven inch blade of the circular saw with a positively lethal fourteen inch chainsaw bar. I did not do a very good job, leaving a wavy cut as opposed to a line that was flat in the center and gracefully curved near the ends. Even in such a relatively straight-forward timber there is also a need for a bit of bevel as the timber curves up the side of the ship. After being cut, the timber ended up having a small amount of what appeared to be punky or rotten wood near the edge, but as we worked on it most of this ended up being carved away.
Donal and I spent the rest of the day trying to get the floor timber fitted in, and mostly ended up getting frustrated by the process. We are not clear on how precisely these timbers must fit, as the planks will swell as they absorb water, and will be forced against the timbers by the pressure of the water. Are we fitting the floor timber to the exact contour of the planking, or are we to create an ideal curve that the planks should conform to later on? Without Gerald’s years of experience, we do not have a good sense of how to tell when good enough is “good enough”.
Tony had a dreadfully nasty job, figuring how to support a keel bolt over a foot long that had to be clinched from the top. He used a hydraulic jack, but really needs a 1 1/2 inch wide piece of bar stock or rod stock about three or four inches long to use as an anvil that will fit in the countersunk hole the bolt is recessed into. This had to support the head of the bolt while Mark was doing the pounding from the top. Mark ran into the problem of not being able to fully clinch over the end of the bolt, as it is also recessed in a countersunk hole. He ended up using a ball-peen hammer as a striker, hitting it with a four pound engineer’s hammer. Needs must, but this is pretty dangerous, as the ball-peen hammer could shatter under this kind of treatment. A bit of discussion determined that a cut off railroad spike might serve, but we have not located one yet.
Gerald ended the day giving us some lessons on how to fasten the planks to the timbers using treenails (pronounced ‘trunnels’). A treenail is a round peg 7/8 inch in diameter and seven inches long made from black locust. Eventually each plank will have two treenails at each point it crosses a timber or futtock, but for now we are putting in only one, with a removeable bolt replacing the second treenail. This is to allow the planks to shift a bit as the ship is built and the timbers and planks ease into their final positions, including any shifting when the planks absorb water and swell up. If both treenails were put in prematurely, this could cause strain and splitting of timbers and planks.
You start by drilling a hole the diameter of the treenail from the inside through the timber and plank. It is more important to have the hole perpendicular to the surface of the plank than to the rib. The hole must be offset away from the centers of both the plank and the timber so the later second hole will not line up with the first, possibly leading to either the plank or the timber splitting.The hole can be hogged out just a bit in the direction the rib runs, making it oval to allow for the treenail to expand when the wedge is driven into it. Shaping the hole to a slight oval shape this way seems to be optional depending on how tightly the treenails are fitting and how exactly the hole is drilled. Depending on how sharp the auger bit is, we often have to use a piece of scrap as a backer against the plank to keep the bit from splintering the face of the plank as it comes through.
On the plank side, the hole is then flared out using a tapered reamer on a brace and bit. The treenail is hammered into the hole from the timber side with good solid blows, square on the flat of the treenail, so as not to split it or mash the end up too much. It is driven in until no more than 3/4 inch is left sticking up. A chisel is used to split it, then a thin wedge made from black locust as wide as the treenail is driven into the split and the treenail is hammered flush with the timber. Since the grain in the timber runs up and down, the wedge and hence the split must run from side to side so that the wedging force is applied to the end grain and won’t end up splitting the timber.
This holds the treenail tight in the timber, now how is the plank side fixed? The treenail is cut off close to the plank, with perhaps 1/8 to 1/4 of an inch extra left above the plank. A pyramidal, four-sided punch is hammered into the treenail from the plank side leaving a square hole about 1/2 inch deep by about 1/4 inch across in the center of the treenail. Next you have to ‘bruise’ the end of the treenail, breaking up the wood fibers, mashing it a bit. This will cause the punch hole to close up, and cause the edge of the treenail to mushroom and flatten a bit.
The punch is driven in once more, and this gives you a chance to see how well broken up the wood fibers are: If the punch merely splits the treenail leaving four cracks and pretty intact quadrants of wood, then the end has not been broken up enough. Unless the wood is uniformly broken up the cracks will later allow water to leak past the plank and force you and your shipmates to spend your time pumping ship as opposed to swilling grog and idling on the forecastle.
If you are statisfied with the end of the treenail, you finally drive in a pyramid shaped peg made of black locust. The use of the peg, a three dimensional wedge, causes the wood of the treenail to expand evenly in all directions, which seals the hole in the plank better than if a simple wedge was used, which would only expand the treenail in one direction. The bruising of the end of the treenail makes sure the treenail expands evenly. The taper on the pyramidal peg is quite gradual, about like the point on a wooden pencil. Unlike the wedge on the timber side, the peg is not hammered in flush, but far enough to lock the treenail in the plank, with a depth about the thickness of the plank. The treenail and plug are then cut off flush with the plank using a flexible saw like a japanese ryoba saw.
During the day our work was interrupted by a fearless rabbit that hopped through the boat shed several times, stopping to watch us work as it ate grass. It would linger long enough for us all to notice it, then scamper away before Don Rittner could get his camera set up to photograph it. Every one remarked on it, as it came by several times, letting people come as close as a foot or two before it would move.
Once we got home Saturday night Linda decided to see if there were any Dutch superstitions about rabbits, and did an Internet search and was shocked to find that there is one that says if a rabbit runs through a ship yard that this is a warning to be on the lookout for fire! Linda is already a bit leery of how oily rags, linseed oil and turpentine are being stored, and this motivated her to try to get people to be more aware of how this stuff needs to be stored.
On Sunday, Donal and I continued to work on getting our floor timber to fit. Linda did some more painting, then helped Margaret lay out the next floor timber to be cut. During a break Linda mentioned her research into rabbit superstitions to Greta, and Greta worriedly replied that she had had a dream that the Onrust caught fire! They are now both on the warpath about paint safety.
Everyone spent time discussing how difficult it is to fit the floor timbers. We figure there has to be an elegant way to do this, that would allow us to take accurate measurements from the keel and planks already installed, create a good pattern from these measurements, lay out the pattern on the wood, and then to cut the timber accurately.
