Frames Update

On December 29 we had all the floors made for the next set of 7 frame pairs. The old fastener holes in the good planks had been filled with fir sticks and the bung holes had epoxied-in fir bungs to return the planks to as-near-a-new-state as possible. Of course, we didn’t plug fastener holes in planks that we planed on replacing — generally all of the planks above the water line. We had planed out the small undulations in the mahogany strips from the re-sawing. We were ready to start laminating those strips into new planks, but the bronze clench rings hadn’t arrived. We needed the clench rings for the drifts that attach the floors to the keelson. Without tightly fastened floors, it is difficult to precisely position and clamp the frames during lamination.

Anticipating that we might not get the clench rings in time, we had prepped the planks in the areas where 8 intermediate frames lie. Mahdee has 11 intermediate frames spaced throughout the mid-section — two near the foremast and the rest around the mainmast. The yard shipwright has said that this is the first and only boat he has seen with intermediate frames. So they are not common. These frames span from bilge stringer-to-bilge stringer. The middle of the frame is centered over the keel and the frame bolts to the side of the floor opposite the normal frames.

Fortunately, the floors to which the intermediates attach were already installed (they bolt to the keel and don’t use clench rings). Thus, we were able to start laminating the intermediates while waiting for the clench rings. This was also fortunate, since it was much easier laminating the intermediates without having an interfering floor too close.

Since we are trying to keep as much of the good planking as possible, we are limited to clamping frame laminates near removed planks above the water line. The intermediate frames lie almost entirely below the water line and therefore have few opportunities for clamping. To apply pressure to the frames, we clamp a notched board to the deck beams and use 2x boards to brace and press the laminates tightly to the hull. If there is not enough pressure, holidays/voids will occur between laminates which will weaken the frame. Conversely, if too much pressure is applied, all the epoxy will squeeze out — also resulting in a weak frame. The upshot is that once braced with lots of boards pressing evenly, it is hard to walk past the frame, so we started framing with the most forward frame and worked backward so we could exit Mahdee easily.

The first intermediate frame required a substantial 7/8″ bevel. We were concerned if it would bend enough in the sharp, vee-shaped bow and tried a dry fit. But, as we pressed the laminates into place, we realized that the stack would jam against the hull and be almost impossible to remove without damaging either the hull or the frame. So, we decided to epoxy up and fit it in. The frame was almost in position when the bottom bevel cracked with a loud bang. Thinking quickly, we decided to separate the bottom bevel to lie up against the hull where it was most needed. Then with another bang, the top bevel shattered. We tossed it aside. Then a third bang when the port side bottom bevel cracked in half just above the bilge stringer line. Fortunately, all of the problems were fixable on the bench afterward.

The next and subsequent intermediates required much less bevel and went in easily. Brenda said “maybe we should have started near the middle where no bevel is required and work forward. ” But as John pointed out, “then we would have become cocky” due to our easy first successes. This way, we were really focused on not breaking any more laminates.

Just as we finished the last of the 8 intermediates we had access to, the clench rings arrived. I drifted in the next floor and we were laminating the respective frames within an hour of the postal visit. This run of laminating was originally planned to do 7 frame pairs (14 frames). With the addition of the 8 intermediates, we are now up to 22 frames in the run starting December 29. As of today, we have 16 out of 22 done and will have the remainder done early next week. Then there will be some cleaning up of the frames and installing to do. That leaves about 19 frame pairs and 3 intermediates still to do — almost all in the aft end of Mahdee.

David

Fire onboard!

Those are words no one wants to hear, but especially when on a wooden boat. Granted its worse when you are in the middle of some ocean, but it was bad enough in the middle of the boatyard surrounded by other wooden boats.

I was using the sawzall to remove part of a frame in the forward section of Mahdee. Anyone familiar with such a tool knows that it not only cuts, it can shake something fiercely. This was especially true since Mahdee’s forward framing was virtually nonexistent. Then there was the saw blade. It was getting dull and of course that makes everything harder. In fact the blade was starting to smoke more than cut. I should have replaced the blade, but that meant duck walking over the top of the boat trying no to knock out a fluorescent tube in the lighting that was on the shed roof only 2-3 feet above the deck to the far side of the boat where a ladder was lashed to her side (we still didn’t have scaffolding up around the boat). That journey was too much effort, and the cutting work was just about done.

I paused for a moment and in that moment I looked aft to see a large cloud of white smoke coming out of the cracks in the deck and coverboard. For a moment I tried to reconcile how me cutting where I was could cause smoke to appear 5 feet aft of where I was working, but then I switched thoughts to the consequences. I was on a large wooden vessel that if it caught fire would probably go up in smoke in an instant. I yelled out to others in the yard “fire on Mahdee near frame 20 on the inside” and started to scramble for a water hose. I remember one being near the front of the yard, but that was way too far for a hose to reach Mahdee. The other workers were scrambling too. One ran for an extinguisher, another filled a bucket of water and a third, Renee, went inside. About the time the extinguisher and bucket were arriving at the base the ladder, from inside Mahdee, Renee yelled that all was now well.

I was doubtful that so much smoke was due to a fire small enough to be extinguished by one person with no water or extinguisher, so I went to check it out. Renee said there was no fire and that the “smoke” was from a WD40 can that fell off the clamp and wedged against the planks so that the button was depressed. What I saw was a cloud of WD40 blowing out of the cracks in the deck and hull. Thank goodness for that.

On the positive side, we put fire extinguishers where we should have had them all along and left the bucket of water on the deck for easier access should a real need come along.

David

Frames

The first goal we had after buying Mahdee in August 2006 was to determine if we could afford to get her back into shape. The first months were a roller coaster with moments of discovery that the boat was in better condition than expected, and moments where we realized things were worse than expected.

On the positive side, the previous owner had removed so much of the interior that we had easy viewing access to most of the hull. Some of the frames (ribs) looked pretty bad, but many others appeared solid. During my first days aboard Mahdee while she was still afloat, I monitored the water in the bilge and it was constant with no bilge pumping. Thus, she wasn’t taking on water. During the tow across San Diego bay, the boat hit large wakes from the spirited piloting of nearby Navy and Coast Guard boats. I had insisted that the tow company place powered bilge pumps on Mahdee (Mahdee had no engine or electrical system onboard with which to dewater). Upon arrival at the haul-out point, the bilge water was still unchanged (which I am sure convinced the tow operators that I was overly conservative).

The boat movers put Mahdee on a truck trailer and transported her to her new home in the boatyard. The hull was solid and tight which gave me further confidence that much of her structure was solid. Pulling the garboard planks (bottom planks) was difficult due to the number of bronze screws and fully intact nails. We used a hole saw to drill out around the nails (thereby destroying the planks which we expected to replace anyway).

Up to this point, all the evidence was much better than expected. We had a solid boat which didn’t leak. We though we might get her back into the water in half the time alloted. Removing the planks above the garboards was too easy. A couple hits with a hammer and a 30+ foot plank would peel off the boat bottom unassisted. The nail fasteners on these planks were rusted down to thin wires at the plank-frame interface. Under the bungs, the nail heads were often in great shape, but the rest of the fastener was gone. This made me really worry about other iron fastened boats we had been on where the owner insisted that the nail heads were in great shape, and thus the rest of the nail was too. I suspect that those boats are in much less seaworthy condition than their owners realize.

Many of the frame heels were known to be bad from our original pre-purchase assessment. We expected to scarf in new heels to frames (where they attach to the floors) that were otherwise good. Some of the floors (floor beams that tie together the frames and the keel) where also known to be bad.

Following the example of what the yard had done with previous boats, we rented a pressure washer/steam cleaner to get the gunge out of the boat. With the garboards off, the gunge could be washed right out the bottom of Mahdee. When the steam cleared, I was surprised at how little was left of the forward frames. It seemed that the painted frames’ strongest component had been the paint. We had planned to replace most of the forward frames, but now there was no question. In fact, the structural integrity of the forward section of the boat was in question. We had to install station molds to stabilize Mahdee.

The degradation of the forward frames could be attributed to the design of the forward deck bulwark stanchions (where frames extended through the deck) which allowed water to leak down and rot the frames. It could also be attributed to electrolysis from the time when that part of Mahdee housed the gas-electric generators and battery banks. It could also be due to the lack of ceiling in the forward area (which creates a chimney effect to ventilate and evaporate moisture). It could also be due to the paint which holds moisture in the frames. The degradation could also be due to the pounding physical abuse the bow takes in heavy weather, or most probably a combination of all of the above.

We decided to address all of those points. The repair design will have the frames end below the deck and have separate bulwark stanchions which don’t penetrate the deck. There will be no generators in this part of Mahdee. We will install a ceiling on unpainted frames. And, we decided to use both double sawn and laminated frames. The forward most frames are double sawn, then every other frame is laminated. Double sawn frames are known for their strength. Even the laminated mahogany frames will be much stronger than the original steam bent oak.

Frames are analogous to the studs in the wall of a house only a lot more complicated. There are very, very few right angles on a boat. The frames should be at right angles to the keel in the horizontal plane — as seen in a birds-eye view. The actual intersection angle with the keel, however, is almost never a right angle since the hull has some vee shape to it. The outside edge of the frame has to match the angle of the curved hull planks which is a constantly changing angle that can be very large near the bow of the boat. Likewise, the inside edge of the frame has to be parallel to the outside so that clamps and stringers will sit flat against the frames. The cross-sections of a frame are parallelograms with different angles at every point along the frame. Double sawn frames require these angles to be cut and planed onto solid pieces of wood. For laminated frames to lie correctly, the top and bottom laminate must be a wedge-shaped piece for all but the amidships frames. Thus making frames is not easy.

Amidships and aft, the frames were mostly unpainted and seemed solid. As work progressed on the forward section frames, we decided to take a close look at the amidships frames. All of the planks on Mahdee had been refastened so that each plank/frame intersection had at least 4 bungs covering iron/nail fasteners. First we drilled out some of the iron fasteners. They were mostly gone and for at least two fastener locations per plank, the drill would go through easily with only iron oxide coming out around the drill bit. Our plan was to leave the more solid iron fasteners in and put 3″ #18 silicon-bronze screws in the remaining 2-3 fastener points.

We could get the new bronze screws to be tight, but that required virtually no drilling — the screw was able to self tap in the frame. The yard shipwright thought that the screws were tight enough to hold about 5 years. Then the frame would be shot and need replacement. We didn’t plan on spending the time and effort to redo Mahdee and her interior just to have to rip it out in 5 years for reframing. To test his opinion, I cut a section of one of the nicest frames and took cross-sections. The blackening of the wood and puddy-like substance on the new screws I took back out showed significant degradation of the wood. I now have to agree that the strength of those nice looking frames is only a fraction of what they were when new.

In our original assessment of the boat, we decided that the rebuilding would be within budget even if we had to replace all of the frames. We knew there would never be an easier time to do it (interior removed). So, we might as well plan on re-framing the entire boat and sleep easier. In retrospect, the reason Mahdee seemed to be in so much better shape than she actually was, was because she was originally so over-built. The frames are over 2.75″ square on 12″ centers. Most of the heels are embedded in pockets in the keel. To relieve stress on the garboard planks, Mahdee has 11 intermediate frames which span bilge stringer to bilge stringer and bolt to the other side of the floors from the regular frames. The upshot is that amidships, there are areas with very little plank showing on the inside of the hull. The yard shipwright wryly noted that we could add a few more frames and then have no need for planks.

As of today, we have 24 new frames pairs installed– 10 double sawn and 14 laminated. By the New Year, we will be ready to laminate 7 more frame pairs, have one more double sawn installed and be ready to laminate 9 of 11 intermediate frames. I think we are past the halfway point in framing and for the first time since August, I feel the boat is becoming more solid.

David

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