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Stambaugh Sailing Skiff Build in Virginia Mountains

I work in spurts. With the sheer strakes in place, it's time to fit the outer stem. To match the inner and outer stems as closely as possible, I used a technique from Sam Rabl's Boatbuilding in Your Own Back Yard.

I attached the outer stem loosely, and then ran a Japanese saw between the two parts. It took two passes to get a close enough thank-goodness-for-the-gap-filling-properties-of-epoxy fit. It's important to remove any screws before hitting them with the saw.

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Outer stem is fitted.

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It took quite a bit of trial and error to get the outer stem to fit the boat "as built," rather than "as imagined." Yesterday I finally installed it, with expensive #14 x 4" bronze screws and generous quantities of gap filling epoxy. The dowels are plugs for screw holes and will be cut off flush after the epoxy cures. The forward face of the stem will be covered with heavy biaxial glass tape.

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Glassing the sheer strakes and stem was the last step with the boat upside down. So, time to prepare for flipping. I supported the weight of the boat with webbing and ratchet straps, and also rigged rope slings.

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With the boat levitated, it was time to remove the strongback. All that remains are the sawhorses, which will support the boat when flipped.

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I have helpers lined up for tomorrow, and did not really intend to flip the boat today. But I removed the ratchet straps and webbing, so only the rope slings were supporting the boat. Then I gave one rope a little tug, and over she came halfway.

I was surprised how easy it was. Ain't physics wonderful?

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So it made sense to continue flipping, and to lower the boat so she rested on the sawhorses.

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Time to have a beer and celebrate!
 
With the boat right side up, I spent lots of time scraping epoxy drips and filling glue joints. This was not a very photogenic operation.

Then it was time to level the boat. Leveling fore and aft required establishing the baseline. The forward end was easy. The baseline and sheer strakes all intersect the stem in the same plane. A simple screw eye on the stem CL located this intersection.

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Locating the baseline aft required more thought. The plans show the baseline intersecting the plane of the inner transom surface 5 inches above the top of the transom. I made a temporary structure to project that plane upward.

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A mason's line level helped locate the baseline correctly. Pink string is essential for this operation.

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Three carpenter's levels and two plumb bobs assured me that everything was level athwartships.

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With everything level, the boat is chocked and braced.

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I don't especially like the way the seat risers are designed on this boat. In traditional skiff construction, the risers are usually inside the frames and are often continuous from bow to stern. For the Sailing Skiff 15, the risers are drawn in three short sections and do not always bear on a frame. I guess they are intended to be glued and screwed to the inside of the planking. I had previously installed the after section of the riser for the stern sheets.

I didn't want to make screw holes in the fiberglass sheathing, so I opted to just glue the risers to the inside of the planking. I made a simple jig to hold them in place with wedges. I have really come to appreciate wedges on this project, and there are a couple boxes left over from the homemade clamps for installing the sheer strakes.

resized riser jig.jpg
 
Moving from stern forward, it's time to trial fit the centerboard case. I won't be able to accurately determine the height of the center thwart risers until the CB case is fitted.

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I sure don't want to install the CB case as designed, with big screws going through the bottom of the keel. That would be a certain recipe for leaks. Instead, I will rely on epoxy and some generous fillets to fasten the case.

I scribed the bottom of the case to fit the bottom of the boat. Here I am spiling a piece of OSB to make a pattern for routing the bottom of the case. I can be much more accurate with a router pattern than sawing freehand with a circular saw or bandsaw.

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I made a mockup centerboard case from scrap lumber for practicing my cutting techniques. Using the circular saw yielded a pretty ugly cut. This was not the way.

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The bandsaw could, in theory, make a more accurate cut. But the little Shopsmith saw from 1957 bogged down in the cut. I needed more power.

A trip to the farm co-op yielded a 5 inch pulley to replace the saw's original 4 inch driven pulley. The new pulley had a larger bore than the original, so I also bought a bushing and drilled it to accommodate a setscrew. The new pulley also required a longer drive belt. There just happened to be a Harbor Freight link belt in the junk collection.

resized new bandsaw pulley.jpg
 
Changing the pulley gave the saw 25% more torque. This was just enough to enable it to cut the centerboard case, a 5 inch thick sandwich of hardwood, plywood, and fiberglass. However, the cut required a very slow feed rate and the saw protested. Don't try this at home, guys, find a bigger saw. I will still have to clean up the cut with hand saws and planes.

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UCanoe_2 said:
the centerboard case
Click to expand...

UC2, could you briefly describe what the centerboard does and how it works in the centerboard case for us non-sailors. Is it raised and lowered to different heights (depths) for different conditions? How? Why?
 
I will explain centerboards shortly, Glenn, but first I should show how to make wedges. They are easy on a table saw, radial arm saw (shown here), or bandsaw, using a simple jig made from scrap lumber. Two identical wedges with their sloped faces together will have their outer faces parallel, as you will see if you look closely at #31 above.

resized wedge_01.jpgresized wedge_02.jpg
 
OK, back to centerboards, and time for a simple physics lesson. If a boat is to sail in any direction besides directly downwind, she has to have an underwater structure that resists sideways drift.
Remember vectors from math class? A sailboat's direction of motion is the resultant of the wind's force and the resistance of the boat.

physics of sailing vectors.jpg

The underwater structure can assume various shapes. A traditional large sailing ship, like the USS Constitution, had a large straight keel. Constitution's keel is no longer perfectly straight after over 200 years in service.

resized constitution keel.jpg

Modern sailing vessels have other types of keel shape.

Types-keels.gif

Traditional Dutch boats have leeboards, like Grumman sailing canoes.

dutch leeboard.jpg
 
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