Saturday, December 31, 2011

Ribbands and Frames

The frames come from green oak flitches. In a boat of Silent Maid's size the rough lumber is 2 inches thick and 10 feet long. Handling these can be a brutal task for men and tools alike. The planks are wide and a good flitch will produce two frames along either edge. The centers are dried and used for other boat parts such as floor timbers.
While the frames are milled the ribbands are wrapped around the mold. Ribbands are temporary, just to bend the frames around, so the wood is rough and they are located to provide a good form for the frames and in a way that makes bending the ribbands themselves as easy as possible.

Our old steam box looked like it had been built to last one year but got used for ten, and it didn't have the capacity we needed for Silent Maid's inch and three quarter square frames, so we decided to replace it. This box is built of HDO ply glued together with the framing on the outside. The bottom is cambered so condensate drains back into the water can. It is in sections so the length can vary according to the job at hand. The end doors pivot on a pin so they are self closing as frames are pulled out. Every second counts. It is our deluxe model.

We started bending frames in the middle of the boat thinking the curvature would be moderate there. The steamer worked wonderfully but we kept breaking frames. The wood grain was good and we tried several clamping arrangements but it appears the frames are too heavy for the bend and most will have to be kerfed. So we moved forward to use up the frames we had in the box and that went well. When frames break it is important to remember this is a rudimentary physics problem and no reason to panic, get noisy, or otherwise ruin the afternoon. Steam bending frames is a great team sport requiring good organization as well as the ability to think on one's feet.

Framing is nearly complete but the better part of a week will get spent tweaking things and getting paint on the surfaces that will be inaccessible later. Every phase of building the boat has this small space to catch ones breath.The big push of framing is over and the loose ends are being attended to. The next big job is already started, making floor timbers, but that is probably worth another page. Real building doesn't go in a linear way, jobs overlap and sometimes efficient use of manpower causes things to happen out of order. A boat of any size built by more than two persons jumps around like the plot of a novel rather than like a train going along the tracks from beginning to end. So the patterns for the floors are made and the next narrative has been set up.

No comments:

Post a Comment