Additional Keel Work And New Look
on Monday, January 19, 2015
As I mentioned in the previous posting, work would be slowing down for awhile while I save additional funds for more lumber. Fortunately, work hasnt come to a complete standstill. Ive been using the time to adjust the fit of the keel and the stem. The keel lies in notches cut into the apex of each frame and into a notch cut into the stem. It will be bolted to the stem with two 3/8" bolts and attached to the frames with epoxy and wood screws. The following picture, although an earlier picture that doesnt show the final cuts, shows how the keel lies in relationship to the boat structure.
What needed to be adjusted was the the height of the notches, both in the frames and in the stem. The end goal is a two-piece laminated keel that is flat from the transom to just aft of frame 4. It is imperative that it be flat in order to not introduce instability into the handling of the boat at higher speeds.
Since the keel, frame notches, and stem(and its associated notch) are all interconnected, I had to play around with various aspects of the fit. This included simulating different depths of the notches, re-positioning the stem vertically, checking and rechecking the height measurements I took several weeks ago for the stem, and insuring that enough wood remained above the notches to provide a complete resting space for the skins after I eventually fair the hull structure.
Readers will remember that the hull structure must be faired (shaped) in order for the plywood skins to lie flat on the structure. This next picture, again an earlier version during test fitting, shows how the parts must be larger than the notches. When the fairing is completed, all of these parts will flow smoothly into one another with no gaps or high spots.
So the goal of fitting is to get the flat keel that I am after while insuring that adequate material is left for fairing. One of the items I wanted to insure was that the stem was mounted correctly in the vertical direction. When I made these parts earlier in the year, I made rough measurements for the slot in frame 5 to accept the stem. It turns out, after carefully studying the plans, that this slot was 1/2" too deep! This in turn made it seem that I didnt need to cut much of a notch in the top of the stem.
This next picture shows that. You can see the stem fits all the way into the slot on frame 5 and the notch to accept the keel is approximately the same depth as one piece of the keel. Remember that the keel is actually two of these boards laminated one on top of the other. This meant that nearly all of the second keel would have been faired away at this point. Trying to cut the notch deeper would have caused the keel to bow unacceptably further aft. I would have also had to cut the notch in frame 5 too deep.
In order to correct this I needed to absolutely establish the length of the slot in frame 5 to insure that the stem was in the correct vertical position. I took the plan measurements for the height of the frame, subtracted all of the measurements except for the distance from the slot closed end to the top of the floor timber to get the distance from the stem top (bottom in the photo) to the floor timber edge. This was supposed to be three and one half inches but was actually 3 inches. So I added a 1/2" shim in the slot and started rechecking the fit of the keel. After this re-positioning, things looked much better.
I was now able to cut a deeper notch into the stem and have adequate keel material remaining even after fairing. And the bow that would have been introduced otherwise went away. I am somewhat embarrassed by this mis-measurement of the slot depth, but I am glad that I found it before gluing everything together.
So this morning I glued in the shim and I will be cutting some water drainage cutouts in each frame notch.
For now, that is where I am at. When I get some more pictures, I will post them as well.
One last thing. I have been working on an alternative color scheme for my boat. Sometime ago, I decided that an all natural wood finish was going to present a maintenance requirement that I was not prepared to accept as I got older. Namely, having to sand down and re-apply varnish on a 2-4 year basis. I also felt that the additional wood on the hull would add weight that I didnt really want. It would also add considerable cost to the boat. After a lot of deliberation, I decided that I would rather have a painted hull and reserve the natural wood finish to the cabin and deck.
So I worked on many variations of paint schemes, rejecting many and keeping others. Eventually I settled on the one that now adorns the top of the blog page. It is a combination of white and blues on the hull with natural wood sides on the cabin and some additional white paint on the cabin roof. I wanted something that was going to look good with the additional height I had in mind for the cabin. I hope you like the final result.
So with that, take care.
What needed to be adjusted was the the height of the notches, both in the frames and in the stem. The end goal is a two-piece laminated keel that is flat from the transom to just aft of frame 4. It is imperative that it be flat in order to not introduce instability into the handling of the boat at higher speeds.
Since the keel, frame notches, and stem(and its associated notch) are all interconnected, I had to play around with various aspects of the fit. This included simulating different depths of the notches, re-positioning the stem vertically, checking and rechecking the height measurements I took several weeks ago for the stem, and insuring that enough wood remained above the notches to provide a complete resting space for the skins after I eventually fair the hull structure.
Readers will remember that the hull structure must be faired (shaped) in order for the plywood skins to lie flat on the structure. This next picture, again an earlier version during test fitting, shows how the parts must be larger than the notches. When the fairing is completed, all of these parts will flow smoothly into one another with no gaps or high spots.
So the goal of fitting is to get the flat keel that I am after while insuring that adequate material is left for fairing. One of the items I wanted to insure was that the stem was mounted correctly in the vertical direction. When I made these parts earlier in the year, I made rough measurements for the slot in frame 5 to accept the stem. It turns out, after carefully studying the plans, that this slot was 1/2" too deep! This in turn made it seem that I didnt need to cut much of a notch in the top of the stem.
This next picture shows that. You can see the stem fits all the way into the slot on frame 5 and the notch to accept the keel is approximately the same depth as one piece of the keel. Remember that the keel is actually two of these boards laminated one on top of the other. This meant that nearly all of the second keel would have been faired away at this point. Trying to cut the notch deeper would have caused the keel to bow unacceptably further aft. I would have also had to cut the notch in frame 5 too deep.
In order to correct this I needed to absolutely establish the length of the slot in frame 5 to insure that the stem was in the correct vertical position. I took the plan measurements for the height of the frame, subtracted all of the measurements except for the distance from the slot closed end to the top of the floor timber to get the distance from the stem top (bottom in the photo) to the floor timber edge. This was supposed to be three and one half inches but was actually 3 inches. So I added a 1/2" shim in the slot and started rechecking the fit of the keel. After this re-positioning, things looked much better.
I was now able to cut a deeper notch into the stem and have adequate keel material remaining even after fairing. And the bow that would have been introduced otherwise went away. I am somewhat embarrassed by this mis-measurement of the slot depth, but I am glad that I found it before gluing everything together.
So this morning I glued in the shim and I will be cutting some water drainage cutouts in each frame notch.
For now, that is where I am at. When I get some more pictures, I will post them as well.
One last thing. I have been working on an alternative color scheme for my boat. Sometime ago, I decided that an all natural wood finish was going to present a maintenance requirement that I was not prepared to accept as I got older. Namely, having to sand down and re-apply varnish on a 2-4 year basis. I also felt that the additional wood on the hull would add weight that I didnt really want. It would also add considerable cost to the boat. After a lot of deliberation, I decided that I would rather have a painted hull and reserve the natural wood finish to the cabin and deck.
So I worked on many variations of paint schemes, rejecting many and keeping others. Eventually I settled on the one that now adorns the top of the blog page. It is a combination of white and blues on the hull with natural wood sides on the cabin and some additional white paint on the cabin roof. I wanted something that was going to look good with the additional height I had in mind for the cabin. I hope you like the final result.
So with that, take care.
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