Much of the last two days was spent bolting and screwing frames into Mahdee. Ten of the 22 frames in the last “batch” are now fully installed. Two more are ready to install, but the yard carpenter has been working on the foremast step which has kept me from being able to install the two intermediate frames that pass under the step. Actually, those frames were ready to install before the carpenter started on the mast step, but we needed to drill out the bolt holes for the keel fairing. We couldn’t do that, because the fairing hadn’t been made yet. John took care of that last point yesterday. So now we need to pull the new mast step out, drill the holes and then the work flows forward again culminating in all new floors and frames in the forward section, a faired keel, along with a new mast step!
But I digress. The point was that installing the frames was slow and painful. The root of the problem is too much wood and not enough air near the keel. This problem is accentuated in Mahdee’s midsection where there are many intermediate frames, and more significantly, the floors are thicker. I can say in hindsight, we got really lucky and installed the thick floors first. I remember after completing the frames up to 17, I was planning how to attack the mid-section. We wanted to do every other frame, but the question was whether to start with 18, or 19. After some contemplation, I picked 18. I don’t remember all of my reasons for that decision, but I do know that floor thickness wasn’t one of them. The even floors are attached by bolts which extend through the keel. The odd floors are attached just to the keelson by drifts. To carry the load of the keel, the even floors are up to 4 inches thick. The odd floors are generally 2.5 inches thick.
Some of the even floors had bolts very close to the front edge. In several cases, the thin wood next to the bolts had disintegrated. To prevent that from happening to the new floors, we wanted some more mass there. This means that a couple of floors are now about 4.75 inches thick (which gives us over 1″ of wood next to the bolts). That is all great until you try to drill and bolt the frames to the floors. To make things easier, I generally predrilled the floors. If we take our 12″ centers for the floors, and subtract the floor thickness and the frame thickness, we have as little as 4 3/8 inches left for the drill and drill bit. Actually less, because the bolts in the adjacent frames usually line up which can eat up another 1/2 to 3/4 inch. The bottom line is that the drill bit has to go through 7 5/8 inches of wood. Clearly this is impossible. You can’t even get the drill bit into the predrilled floor, let alone the 8 inch bolt.
So we were fortunate that the thick floors generally went in first. I could tap the heel of the old oak adjacent frame and it would turn to powder and give me about 3 inches more room. This would not work if the adjacent frame were one of our new mahogany wonder laminates. Having 7 1/4 room to drill out 7 5/8 inches is not ideal, but it is usually possible to angle in the drill bit (and later on the bolt).
In the fore-section of Mahdee, I was able to use my big Milwaukee 1/2 angle drill due to the thinner floors and, more importantly, the curvature of the hull. In the midsection, I was stuck with a 3/8 angle drill and a set of 3 different lengths of drill bits. Step one, hammer in the shortest drill bit into the predrilled floor. Step two, get chuck onto end of drill bit. Step three, drill until chuck hits floor (optionally blowing compressed air on the drill windings if the rotor is jammed up and there is no room to run the drill in reverse). Step four, un-chuck drill and grab end of bit with vice grips. Step five, use crowbar and hammer to pull out drill bit. Then go to next size bit and repeat! On the last bit, it was usually necessary to re-chuck the drill after step 3 so that the chuck was barely holding the bit to get that last little bit of depth. In the worst case, it was also necessary to hammer the drill bit through the last 1/4 of purple-heart (using a chisel on the other side to limit tear-out).
Needless to say, drilling took lots of time. One morning, I managed to only get four bolts installed. I imagine that in building the boat from scratch, one would work sequentially and then have no need for any special drill — what a luxury. My big worry is that we had to skip the fat floor at frame 24 because the keel bolts land on top of keel blocking. I may need to get even more creative to install the frames on that floor.
The remaining 10 frames in this batch will be ready to install next Wednesday. After laminating, we let the frames cure for two days in the boat. Then we pull them out and sand the sides smooth. The sides are coated with epoxy to limit the likelihood that enough water is absorbed into the frames to cause the glue-seams to fail. All told, it is about a week after laminating before the frames are ready to be bolted to the floors. At the same time, we fasten the good lower planks to the new frames with screws. The clamp and shelf bolts are also installed at that time.
David
