New Frames
With the completion of the installation of the new transom, the next step was to steam-bend new frames. However, there were still a few issues with the planks to address. I had already replaced a few sections of the lapstrake planks where severe rot was present (see Lapstrake Repair), but there were a few areas remaining that had minor rot issues that needed repair. In these cases I used a mallet and chisel to carve out the rot and then replaced it with new 1/16" thick Mahogany veneer. In a couple of areas I had to carve deeper and needed to apply two layers of the veneer with the grain of each veneer layer laid in opposing directions. They were glued in place with epoxy thickened with colloidal silica and temporarily stapled with plastic staples (until the epoxy cured). The new veneer patches were then sanded flush (the plastic staples can be sanded off leaving barely visible plastic filled staple holes) and the entire interior of the boat was coated with penetrating epoxy to help prevent any further rot damage. Here's a before/after picture of an area that had rot damage... not enough to warrant cutting out the plank section, but enough to replace the outer veneer layers.
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I had greatly underestimated the amount of damage and work involved in getting this hull back into usable condition. A lot of the damage was hidden under the paint. It wasn't until the paint was stripped off and the frames removed that it became obvious just what precarious condition the plywood hull was in. Most of it was confined to the interior of the boat. These plywood boats of the 60's were not designed and built to last a long time. When the boat was built the lapstrakes were installed over the frames with no protection (no paint nor sealer applied... just bare wood exposed) where they were most vulnerable, thus the rot issues. Once the frames were off much of the rot damage became obvious. Knowing what I now know, and feeling the anxiety of working through this (for a while there I felt that perhaps this project should be abandoned), I probably would not have recommended that this boat be restored. But I was committed to completing this project so I pressed on repairing each instance of rot as I encountered it. In addition to the rot there was delamination issues. The outer most veneer layer, in many areas of the bilge, literally came off by just rubbing my fingers over it. Also some of the glued lapstrake joints were failing due to delamination of the of the outer veneer too. This outer most Mahogany layer was paper thin and I aggressively scrapped off much of it exposing a layer of glue and the thicker Fir plies below. Since the bilge is going to be painted with bilge paint I felt that the exposed glue (the dark areas in the bilge), though unsightly, would not be an issue. I decided to coat the entire inside with penetrating epoxy to help preventing further rot and to provide protection to the hull in the areas where would be covered by the new frames. Lastly I applied epoxy filets to the lapstrake seams below the water line in an attempt to both strengthen the the joints, and seal the end grain.
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I initially intended to install the new frames in two phases. The first phase I would remove every other frame and replace them relying on the old frames left in place to retain the shape of the hull. Then, for the second phase, I 'd remove the remaining old frames and replace them relying on the new frames that were installed in phase one to retain the shape of the hull. But in order to repair the remaining rot damage required me to remove all the frames at once. This left me with two issues to contend with. First I needed to brace the hull in some manner in order to retain its original shape, as well as prevent the hull from twisting. So I braced, leveled, and plumbed the hull with 2x4's. After it was braced I removed the remaining frames and found the hull to be quite delicate and discovered that a a few of the lapstrake seams had separated due to the outer layer of veneer delaminating. So those areas were carefully pried apart, and glued with 3M 5200 and refastened back together and allowed it to cure for about 4 days (3M 5200 takes about 7 days to cure fully).
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Finally it was time to have some fun steam bending the new frames into place. Typically White Oak is used for frames. White Oak is very strong and highly rot resistant. But another unexpected obstacle, where can I find "green" (not kiln-dried) white oak? Green White Oak is hard to find and my two expected sources of green White Oak did not have any available. I was scrambling to find a source and got lucky and accidently found a source less than 5 miles from my shop. In addition to his fine woodworking services, Michael Koppy of Performance Edge - Mindfulness Furniture Making, also sells furniture grade wood from his nearby shop, He had just picked up a load of White Oak from a sawyer in southern Wisconsin and could sell me few boards before he dried them. So from this pile of green wood I milled the new frames.
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With the help of a friend it took us about 5 hours to steam bend 48 new frames into place, breaking only 3 frames in the process (due to grain runout). The 5/8" thick frames were steamed for 35 minutes each. We kept 7 frames in the steam box at a time, installing one every 5 minutes. The Oak was freshly cut as I could feel the wood's moisture content with my fingers as I milled them. They bent into shape very nicely and easily, first bending using my foot to press it into place following up with a few taps of a mallet to achieve a snug fit, and then using a clamp to hold it in place. The next two days were spent fastening the frames to the hull using over 500 silicon bronze screws. With this part of the project complete I'm feeling far more confident that this project is going to be a success.
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