The breasthook adds rigidity to Justine‘s structural elements near the stem head where the sheer clamps and sheerstrakes are attached. It has a triangular shape and lies atop the sheer clamps and against the stem and sheerstrakes.
The sheerstrakes and sheer clamps are fastened to the stem, but the joints would not be very rigid without a structural member that further secures them. That’s the job of the breasthook.
I used off-cuts from the black locust plank I’d purchased for Justine‘s stem to make up a blank for the breasthook. I ended up edge-gluing six pieces, and inserting two 1/4″ bronze drifts into the blank for some extra reinforcement of the glued joints (and with forethought to where future fasteners would need to go). I made a plywood template of the space the breasthook would occupy and began to bring the blank to its final shape.
I glued up six pieces of black locust as a blank from which to make Justine’s breasthook.
I planed a small amount off the sheer clamps so that the breasthook would lie flat against them, then cut the bevel required for a tight fit against the stem. I then used my block plane to plane the winding bevels on the end-grain surfaces that would contact the sheerstrakes. Some patience is required to get all the bevels to fit simultaneously.
The front of the breasthook is bevelled to fit snugly against the stem, and the sides require a winding bevel to match the inside surfaces of the sheerstrakes.
Once the breasthook was fitted, I gave the underside and bevelled surfaces a coat of red lead, drilled for the fasteners, and spread 3M 5200 on the mating surfaces prior to driving all the fasteners. Finally, I planed a very slight crown on the top of the breasthook to match the curvature of the deck beam mold.
I fastened the breasthook with two fasteners into each sheer clamp, one into the stem, and two driven from the outer surface of each sheerstrake.
Afterdeck beams
Justine has a foredeck and a small afterdeck, both made of 9 mm marine plywood. Both decks are supported by white oak deck beams that run athwartship. I decided I’d tackle constructing the smaller afterdeck first because it would be easier and thus a good learning opportunity.
In the Flatfish and Fish Class designs, the afterdeck height lies about halfway between the cockpit seats and the top of the cockpit coaming. The afterdeck is supported by three deck beams, and the deck beams rest on cleats that are attached to the frames between stations 21–23. It’s not obvious from the plans, but these cleats need to have a significant twist, and some curvature, to fit properly against the frames. I made a jig so that I could steam the cleat blanks, then twist them into the correct shape and clamp them in the jig to cool.
To impart the significant twist in the cleats that support the afterdeck beams I made a jig and proceeded to steam them and clamp them into the jig.I steamed the cleat blanks in a tube made of polyethylene sheet, then twisted them and placed them into the bending jig I’d made.
The afterdeck beams are white oak, cut to the afterdeck curvature specified in the plans.
The cleats that suport the afterdeck beams have been fastened to the frames and the first of three deck beams placed in position. The ends of the deck beams rest on the cleats and are fastened to the frames with screws.All three afterdeck beams are in place, and they’ve been painted on all but their upper surfaces. When I lay the afterdeck, I’ll use 3M 5200 where the plywood deck is fastened to the deck beams. Note that the temporary 2 x 4 backing the hull at station 21 has been removed, as the deck beams now maintain the correct beam well aft in the hull. I also used a piece of white oak to made a support to fasten the rear edge of the afterdeck back at the transom.
Foredeck beams
Justine‘s foredeck extends from the stem back to the forward bulkhead of the cockpit. Forward of the cuddy top, the deck beams are continuous from port to starboard. The deck beams are interrupted by the cuddy top, so from stations 10–12 they are half-beams that extend from the shearstrakes to the cuddy coaming on each side of the hull. In this post I’ll just illustrate the installation of the full deck beams up to the forward cuddy bulkhead (from stations 2–8).
Station 2’s deck beam is in place and ready to rivet to the sheer clamp. Once the deck beam was in position, I removed the temporary 2 x 4 that maintained the hull’s designed beam at station 2.
The forward deck beams are fastened with #8 copper nail rivets that pass upwards through the sheer clamps and deck beams. Copper burrs go on the nails protruding from the deck beams, the nails get trimmed to the proper length, and rivet heads are peened atop the burrs.
I made all of the foredeck beams to the curvature of the deck beam mold. Here I’ve got the deck beams ready to rivet in place at stations 2–8, and all but one of the temporary 2 x 4’s are removed from the hull.
The first parts to go into the freshly painted hull are the sheer clamps. Justine‘s sheer clamps are Douglas fir pieces that are 1 3/8″ square in cross section and about 22′ long. I made them up from 12’ long pieces that were scarfed and joined with epoxy. The sheer clamps help keep the hull in its designed shape, they add stiffness, and they serve as a foundation for deck beams in the forward part of the boat and the mahogany covering boards and coaming aft.
In Herreshoff’s Fish class boats and many other designs of his, the ends of the deck beams rest on and fasten to the sheer clamps, while back in the cockpit area they support mahogany “covering boards” that lie atop the sheerstrake and sheer clamps. So the sheer clamps have to dip down in a “squiggle” trajectory amidships to perform these two different functions.
The sheer clamps extend from the stem to the transom along the top of the hull. They help hold the hull in the proper shape and stiffen it, and they also serve as a major component that helps to support the decking. Note the dip (“squiggle”) in the sheer clamps just forward of the centerboard trunk.
The sheer clamps’ squiggles occur over only about four frame spacings, or about 39″, so in this region there is an abrupt curve vertically, superimposed on the gentler horizontal curve from stem to stern. I figured this could only be achieved by steam bending, so I made a jig that would facilitate a compound bend.
I made this bending jig to impart both the “squiggle” between stations 11 and 15, as well as the long curved shape of the sheerclamp as it runs fore and aft.
I cut a 2″ square opening in the closed end of my steam box, and steamed the center section of the sheer clamp. I then clamped the hot piece in the jig and let it cool.
I steamed the midsection of the sheer clamp where the “squiggle” would be, then clamped it on the bending jig.
The sheer clamp also takes a rather sharp curve as it approaches the stem, so in a separate operation I steamed the forward section of the sheer clamp and put a suitable bend in it by re-clamping the midsection to the jig I’d made, and tying the end down to my anvil.
I also steamed the forward section of the sheer clamps, as they take quite a curve as the sheer clamp approaches the stem. I’ve put the sheer clamp in the bending jig, and have pulled the forward section down by tying it to my 120# anvil which is sitting on the ground.
Fortunately, the after end of the sheer clamp is only gently curved and it could be positioned properly without needing to be steamed. Aft of station 15, where the covering boards will go, the sheer clamp is positioned to lie fair along the bevel on the top of the sheerstrake, using the deckbeam mold as a guide.
I’m just starting to clamp the sheerclamp into position. I fitted the forward part first, and allowed the after end to run up over the sheerstrake and hang free for until the forward section is properly positioned and fastened.
The sheer clamp is fastened with rivets made from #8 copper nails. One rivets passes through the sheerstrake, frame, and sheer clamp at each station. Because it is fastened to the inside of the frames, the sheer clamp stands off the sheerstrake by the 7/8″ frame thickness. The holes in the sheeerstrakes are counterbored, the copper nails are inserted on that side, then the rivets are headed over burrs on the inside surface of the sheer clamps. A second rivet secures the sheerstrake to the frame at each station. (Prior to installing the sheer clamps, the sheerstrakes had been fastened temporarily to the frames with screws.) Once all the riveting is done, I bunged the counterbored holes in the sheerstrakes.
The sheer clamp is fastened with copper rivets that pass through the sheerstrake and frames. Rivets also attach through the sheerstrake and frames above the sheer clamp forward of the squiggle, and below it aft of the squiggle.
Back at the transom, the sheer clamps fit into oak blocks that provide the 7/8″ standoff from the sheerstrake and make a firm anchoring point for the clamps. The blocks are made from pieces of 8/4 white oak, rounded to fit against the curved inner surfaces of the sheerstrake and planking. They have a compound miter to fit against the transom, and a 1 3/8″ square rabbet to accommodate the sheer clamp.
Back at the transom, the sheerclamps fit into substantial oak blocks that have curved outer surfaces that fit against the curved inside surface of the sheerstrake and planking. I planed the curved outer face of the blocks first, then cut a compound miter for the fit against the transom. Finally I cut the large rabbet into which the sheerclamp will be bedded and fastened.The block that holds the aft end of the starboard sheer clamp has been fastened in place, and I’ve cut the compound miter on the end of the clamp. It’s ready to bed and fasten.Port sheerclamp fastened in place at the transom.
The bottom and outer surfaces of the sheer clamps got several coats of paint before fastening the sheer clamps in place, and the other surfaces painted afterwards.
The sheerclamps are fastened in place and getting painted. Date of photo is October 29, 2014.
When I was finished building my Biscayne Bay Sailing Skiff, one lesson learned was that the building was only about one-half complete when I began working on the inside of the hull. Building Justine has not been much different.
Completing Justine‘s interior includes adding many, many compon ents. Some are obvious like bulkheads, decking, and cockpit seats and sole. Some are less so unless you are quite familiar with traditional wooden boat construction. Even after completing the interior construction, you still need to make spars, fit the 1200+ pound ballast keel, install hardware, and complete running and standing rigging. And all the wooden parts need paint or varnish. I’ll describe all of these topics in my next posts.
First steps
With the hull right-side up, I began by removing the eight remaining construction molds from the hull.
Just after turning over the hull, you can see the construction molds that I’d left in to both brace the hull and as fastening points for the 2 x 4 crosspieces we used to facilitate carryout and turnover.
The molds are held in place only by the thin steel straps that hold the frames onto the molds. (The straps went on just after the frames were steamed, just prior to bending the frames to conform to the mold shape.) I simply sawed the frames between the straps and the sheerstrake, releasing the molds from the hull one at a time. After removing a mold, I cut a 2 x 4 to appropriate size and shape and temporarily fastened it to the frames with drywall screws, to hold the hull to its proper beam at that station. Then I went and freed the next mold and braced that station with a 2 x 4 and repeated the process until all 8 molds had been replaced with 2 x 4s.
I also needed to protect Justine from the elements, so Annie kindly offered to buy me a capacious 12′ x 24′ Shelterlogic shed for my 66th birthday! It was necessarily a large structure, but I erected it with the help of some friends, and we didn’t drop any parts onto Justine in the process! (And after three Maine winters, the shed is still in very good condition.)
Soon after turnover, I removed the remaining construction molds and inserted 2 x 4s cut to the proper length and bevel to keep the hull’s beam at the designed dimensions. Framing for the shed I erected is beginning to go up, too.
I had left a little bit of extra material at the top of the sheerstrakes, anticipating I’d want to trim that down later. Trimming offered the chance to correct any unfairness to at the sheerline (top of the sheerstrake) and also to plane a winding bevel along the top of the sheerstrake that would match the curvature of Justine‘s deck when it went on.
Justine‘s plans showed dimensions for a “deckbeam mold” that is useful in adjusting the sheerstrake bevels. The deckbeam mold has constant curvature, and it it wide enough to span Justine‘s beam amidships. The suggested use is to plane the bevel angle at each station so it will conform to that of the deckbeam mold when it’s placed across the hull at that station. (I learned as I was getting ready to install the cuddy top that there’s a better way to do this. I have a bit more to say about this when I do a post about building the cuddy top.)
At this stage, it’s also a good time to trim off the tops of the frames so that they line up with the top of the sheerstrakes. And of course, it’s the ideal time to paint the interior of the hull before any other parts are installed. I chose Kirby Paint’s “Green Gray” color for this.
I knew I should give the interior of the hull several coats of good paint while everything was accessible. I’ve also begun to trim the top end of the frames down to their final level, and to bring the top edge of the sheerstrake to its final profile and correct athwartship bevel.
The best way to trim the top of the sheerstrake is to clamp a long batten in place and make any adjustments to bring it (the sheerline) to a fair curve. Sighting along the batten from several perspectives allows you to refine the shape. All the actual shaping is done with a hand plane, working very carefully and paying attention to the grain direction.
I’ve attached a long batten at the top of the sheerstrake to use as a guide in refining Justine’s sheerline to a very fair curve. I am simultaneously beveling the top of the sheerstrake to match the curve of the deckbeam mold that is visible lying across several of the 2 x 4 support pieces.
I still had not fastened the forward ends of the sheerstrakes to the stem, but I knew that they should be steamed so they could be more easily bent into position for fastening. So made plastic sleeves from thick polyethylene sheet that would slide over the first three feet of the sheerstrakes, then fed steam in through a piece of plastic pipe for about 90 minutes, clamped the hot end of the sheerstrake into position, then did the fastening.
I steamed the forward end of the sheerstrakes by inserting it in a tube of thick polyethylene sheet instead of a steam box.
The steaming did not noticeably affect the few coats of varnish I’d already applied to the sheerstrakes.
I’ve steamed and bent the forward-most end of the sheerstrakes and driven fasteners to secure them to the uppermost part of the stem rabbet.
Once this preliminary work is done, the hull looks quite spiffy. You see the inside shape, the varying heights of the floors, the butt blocks, the sheerline, the fresh coats of paint, and feel a sense of anticipation as you’re about to begin adding additional structural members and building out the boat’s interior spaces.
Inside surfaces painted, frame tops trimmed and painted, and sheerline refined—ready for sheer clamps!
My barn was only barely big enough to accommodate Justine upside down on her construction molds. There was about 3′ of clearance between her keel and the barn’s second floor joists, and the door opening was not quite wide enough to carry her outside.
My basic plan was to gather a large crew, carry Justine out of the barn, and turn her over. She was resting on her 22 construction molds, and they added a lot of weight. But it would be necessary to keep several molds in place during carry-out and turnover to keep the hull from deforming. So my first task was to remove all but eight of her construction molds.
Preparation
It was clear that I lacked space to turn Justine over before she came out of the barn. I talked to many people to get advice about how to turn the hull over once she was outside. And I read everything I could about the topic. The technique I decided on I had read about in Howard Chapelle’s book Boatbuilding. This would involve attaching 2 x 4s across most of the construction molds that remained in the hull, extending athwartships. Each 2 x 4 would be the same length, and their ends would be able to act as bearing points as the hull was lifted up, turned over, and rolled upright. The 2 x 4s would also serve as carrying points for the work crew to move the hull out of the barn and into position outside.
The angle brackets holding Justine’s construction molds to the barn floor have been removed and three of the six 2 x 4s I’ll use have been bolted to selected molds. The hull will be jacked up several inches to provide clearance so I can remove the majority of the molds before carrying Justine’s hull out of the barn.With the hull jacked up about 6″ it is possible to get the unneeded construction molds out from under the hull. I needed to crawl under the hull to loosen and rotate some of the molds down onto the floor. Even with the hull upside down, it was exciting to be inside the hull for the first time!
I bolted 2 x 4s to the construction molds at stations 4, 7, 11, 14, 16, 19 and 23. I also kept the molds at stations 2 and 3 in place to maintain the hull’s correct beam in the forward part of the hull until after turnover. All the other molds were removed.
14 of the molds are out and the hull is ready to carry, but it’s obvious that the barn door opening is not wide enough.We removed the sliding door, the clapboard siding, and cut out a section of the end wall to enlarge the opening. That’s Scot supervising.
Execution
I needed a good-size work crew for carry-out and turnover, so we threw a party. Family members, a number of friends from Boston, and Georgetown friends and neighbors showed up to help and cheer us on.
Twelve people were able to lift and carry Justine’s hull out of the barn. The 2 x 4s provided convenient and secure carrying points.
I mostly supervised the carry-out. Some of the carrying crew were grimacing with effort at times, but there were no tense moments. The ramp from the barn was only wide enough for the people on Justine’s port side to use, and there was a process of handing-off the carrying points on the starboard side to people at ground level, but even this presented no problems.
Outside and high time for a crew break!
It was tremendously satisfying to see Justine resting outside. We took a long break and discussed just how we would accomplish the turn-over.
The hull looks impressive out in the sunlight. Here you can see the projecting ends of the 2 x 4s. They’re all the same length, and their ends are all lined up.
Scot and others had a concern that the hull might tend to separate from the molds as it was being turned over, so we secured the hull and molds together with heavy straps.
Straps secured the hull down to the construction molds that remained in the hull and to which I’d fastened the 2 x 4s.
We positioned padding on the ground where we expected the hull to make contact, then commenced lifting very carefully until we approached the (unstable) balance point. We’d attached lines so that people could hold on and prevent the hull from suddenly rolling, and to ease the rate at which she was lowered into position right-side up.
For turnover, there was a group of helpers on each side of the hull. Here, the port-side group is lifting and the starboard-side group is keeping the hull from tipping as it gets near the balance point.Just past the tipping point, the people who had done the lifting shift roles and grab pre-rigged lines that they use to gently lower the hull onto her side.
Once the hull was resting on the keel plank, it could be picked up by the 2 x 4s and moved into position close to the barn.
With the straps still attached, Justine was easily lifted again using the 2 x 4s and set into position close to the barn.
One final lifting enabled placement of blocking under the keel plank and positioning jack stands forward and aft to port and starboard to keep the hull from tipping sideways.
The final task for the group was to lift the hull up so that blocking could be inserted under the keel plank, and jack stands could be placed on both sides to keep the hull from tipping. Scot bravely went under the hull to position the blocking.
Party time! A cookout, sangria and beer, speeches, and a shared sense of satisfaction with a job safely executed. The date: July 12, 2014.
Toward day’s end, Justine is resting securely as the sun goes down.
With the hull still upside down, it’s a very convenient time to do some painting and varnishing because access is so good. I decided I’d get several coats of bottom and topsides paint applied, and build up a good varnished finish on Justine‘s transom before bringing her out of the barn and turning her over.
Marking the waterline was the first step. The load waterline is a key feature in the table of offsets and in the construction plan that were part of the Flatfish plans set I purchased. But the main reference line on the plans for construction purposes is designated as the “construction baseline.” The butts of the construction molds are all cut at this line, and it is effectively the plane of the building floor.
For some good reason, I’m sure, the Flatfish plans do not have the waterline parallel to the construction baseline, so you have to do some interpolation to lay out the position of the waterline on the hull when it is still on the construction molds. I marked the locations on the stem and transom where those parts intersect the waterline, then measured the height of both points above the construction baseline. (My laser level was very useful for this: I set the height of the laser at the mark on the stem, and had the laser scan a horizontal line. Then I had a reference line from which to take measurements 0n other points on the hull.) I measured the horizontal distance from the stem and transom points, then I divided that distance into suitable intervals (about 10). Then I calculated what the waterline height should be at each of the intermediate points, knowing that the waterline on the hull must lie in a plane. This enabled me to mark about 10 points on the hull that the waterline would have to intersect. (Again, the laser level made marking the lines pretty easy.)
Once I had marked a series of points on the hull for the waterline, I lightly tacked a batten onto the hull to connect the points in a fair curve. With the batten in place, I used a saw to lightly score the position of the waterline on the hull planking, removed the batten, and was ready to apply masking tape to the line and apply some bottom paint.
Justine’s seams have been caulked, payed, and smoothed with seam compound. Here I’ve marked a fair curve along her designed load water line.
I used Petit water-based bottom paint and applied several coats. I didn’t apply bottom paint to parts of the keel plank to which the ballast keel, deadwood, and forward fairing piece would eventually attach. These already had been given a good coat of red lead, and eventually they would be covered with these other pieces of the boat and those joints bedded.
I applied several coats of water-based antifouling paint below the waterline, and am building up a good coat of varnish on the transom. The bottom paint and sheerstrake have been masked off, in preparation for painting the topsides.
For topsides paint I used Kirby Paint’s color “Green Tint.” I applied it according to the directions on the can and it took three coats to do a good job of evenly covering the underlying planks and seam compound. I expected to apply at least one more coat once the boat was much closer to launching.
It takes several coats of paint to get a uniform color and gloss because some places are bare wood and some have been covered with seam compound. Here you can still see signs of the seam compound..
Many Herreshoff designs have a distinct concavity in the forward sections, above the waterline. It is hard to capture in a photo. I only have a thin coat of finish on the sheerstrake, as it will be some time before I can bung its fasteners and bring its top edge to a proper bevel.
I also wanted to get a really nice varnish finish on all of Justine’s brightwork, so the outside surface of the transom was where I started. I closely followed the Rebecca Wittman’s excellent articles on “The Art of Brightwork”, Part II, Sanding—True Grit, WoodenBoat Vol. 82, p. 88; and Part III—A Professional’s Approach to Finish Application, WoodenBoat Vol. 83, p. 66. For mahogany, this involves applying several coats of an oil mixture, followed by a minimum of eight coats of varnish. While it’s a long process, it’s not bad if you are in the midst of doing lots of other tasks and have the time to spread the work out over several weeks. And the results are fabulous!
Finally, I purchased a book of gold leaf and some sizing for it, and applied gold leaf to the carved “Justine” on the transom. I read a few articles on how to do this before starting, and I used gold leaf that had paper backing to make the transfer onto the carved surfaces easier than the technique in which the leaf is transferred with a brush. Once the gold leaf was on, I applied one thin coat of varnish over it.
I’ve just finished applying gold leaf to “Justine” on the transom.
I was done with about everything that could be done before turning over the hull. That’s the subject of my next post!
I purchased four 5/4 Honduras mahogany planks, each 12′ long, to use for the sheerstrakes. Because the finished sheerstrakes are about 22′ long, I knew I would be making each of them up from two pieces of lumber. I planed the planks to slightly over the sheerstrake’s 1″ maximum thickness before cutting them to the spiled shape. This left a bit extra for rounding and sanding the thickest part of the sheerstrake.
Sheerstrake lumber ready to transport from Highland Hardwoods in Brentwood, NH to Georgetown, ME.
I decided to do most of the shaping of the sheerstrakes by hand. But I did use my circular saw to make long parallel grooves of appropriate depth at about five locations spaced at fixed distances from what would be the sheerstrake’s top edge. This would give me reference lines that would indicate when I was getting close to planing off most of the unwanted material, after which I could start working toward a smooth and consistent final profile.
I start to shape the sheerstrake by making lengthwise cuts at a fixed distance from the top edge, with a depth that left nearly what the final height of the finished sheerstrake will be. I made about 5 cuts at key points on the profile to serve as guides when I planed and scraped the profile to its final shape. In this photo I’ve already planed the bottom portion of the sheerstrake to its final 5/8″ thickness.I’ve removed most of the material that I can reach with my smoothing and backing-out planes, but the profile is still a little rough and there are still some traces of the saw cuts I’d made.
I did all of the final shape refinement using a cabinet scraper that I’d filed to an appropriate shape. Using the scraper was a slow process, but very effective. It’s important to keep the scraper very sharp and to scrape “with the grain.” (I found it necessary to shift directions as the grain in some of my planks changed.) Early on, I fitted my scraper with a small piece of wood that hung down over the top edge of the sheerstrake to act as a fence that would ensure that the molded profile maintained a fixed distance from the sheerstrake’s top edge.
I did the shape refinement with a cabinet scraper (on workbench) that I filed to a shape that would produce the designed molding. Early in this process I fitted a small piece of wood (not shown here) on the end of the scraper to act as a “fence” so that the molded shape would accruately follow the upper edge of the sheerstrake.
As illustrated on the Flatfish construction drawing, the molded profile gets somewhat thinner approaching the transom and stem. That required carefully planing off some more material, and doing some additional hand scraping and sanding. With all the hand work, I was glad I’d decided to make the sheerstrakes out of mahogany rather than oak (an option on the construction plan)!
Forward section of the sheerstrake, fitted and clamped in place.Half of the sheerstrake, molded, sanded smooth, and given an initial coat of varnish. There is a significant curve, but once clamped in place it is a very good fit!
Once the forward section of the sheerstrake was shaped and fitted against the adjoining cedar plank, I made the aft piece using the same method.
The two halves of the sheerstrake would need to be joined together with a scarfed joint. Anticipating this, I left extra material to remove near the scarfed ends when I created the planks’ molded shapes. I laid out the scarfs with an 8:1 slope, rough cut them on the bandsaw, then overlapped and planed them simultaneously with my 07 joiner plane. This method ensures a very close fit of the scarfs.
I left extra material at the ends of the molded planks I’d be joining together, then planed scarfs at an 8:1 slope in preparation for glueing the pieces together.Scarfed ends placed to overlap. Extra material in this area will be planed off once the pieces are glued.
With the two pieces scarfed and ready to glue up, I needed a method to get them properly aligned so that the long continuous piece would fit properly against the adjacent cedar plank. I decided to use the spiling batten to draw the plank’s shape, from 6′ forward of the scarf to 6′ after it, on a board about 12′ long, then clamp the two pieces together and glue them directly on the marked board, aligned with the line I’d drawn on the board. I used epoxy thickened with silica to bond the pieces together.
After careful alignment with the lines on the board underneath, the two halves of the starboard sheerstrake are glued together.
After joining the two halves of what would be Justine’s port sheerstrake, I finished refining the molded shape around the scarfed joint. I also marked a second set of mahogany planks to make the starboard sheerstrake.
I did all of the work on the sheerstrakes working alone, including fastening them. I found that the best way to clamp them in position was to start amidships, and add clamps working forward and aft from there.
I hung the sheerstrakes working alone. I clamped the plank in place amidships and supported the stern end with a line attached to the barn ceiling, then clamped it position amidships, and proceeded to place clamps working toward the stem and stern.
The sheerstrake’s forward end fastens into the top of the stem rabbet, so that end needed to be trimmed into the appropriate shape. Once that was done, with the sheerstrake clamped in position along its entire length, I put a piece of tape across the sheerstrake and its adjacent cedar plank near the amidships clamp, to serve as a reference mark for fore-and-aft positioning of the sheerstrake when I started fastening it in place. In the process of fitting and trimming the sheerstrake, I clamped it in place, marked it, and removed it numerous times. Eventually, it was ready to fasten.
I’d very carefully clamped the sheerstrake into fore-and-aft position so that the forward end would lie properly in the stem rabbet, then placed pieces of tape across the joint with the adjacent cedar plank amidships, where I would begin fastening. Clamps came off, the plank straightened out, but I was certain the plank would be properly positioned when the pieces of tape were aligned. In this photo, I’ve just started driving fasteners, working aft.
All the sheerstrake’s fasteners are counterbored at least 1/4″ or so in order that they can be covered with mahogany “bungs” and concealed. And, as indicated on the construction plan, some of the fasteners are only temporary, as after the hull is turned over they will ultimately be replaced by copper rivets that also hold the sheer clamps in place.
All the sheerstrake fasteners have been driven except those that go into the stem. There was sufficient twist between station 2 and the stem that I concluded it would be best to steam that section before driving the screws to bring it all the way down into the rabbet.
I was reluctant to fasten the sheerstrake into the stem rabbet at this point because it took a lot of force to bring it into position with clamps. I decided it should be steamed before fastening, and I didn’t do that until after the hull was painted and Justine was right-side up and outside the barn. I also waited to caulk the entire sheerstrake joint until after the sheerstrakes were completely fastened.
Planking completed! A major milestone!
I began planking by installing the garboards in August 2010, and finished installing the sheerstrakes in May 2014.
A key design feature of many Herreshoff boats is a bright-finished (varnished) sheerstrake with a molded shape that is both visually pleasing and functional as a rub rail. Making the sheerstrake is the most challenging part of the planking: The molded shape changes along the sheerstrake’s length, and the nonuniform cross section complicates the spiling process.
The Flatfish construction drawing includes a full-size drawing of the sheerstrake shape amidships and the shape it takes as it approaches the stem and transom. Also included are the sheerstrake widths at the stem, station 14, and the transom. I used the width information for the sheerstrake when I lined off all the planks.
Sheerstrake profile and width information is provided in the Flatfish construction drawing. I added a few measurements of my own on the drawing.
When spiling a plank of uniform cross section, one uses a spiling batten of uniform thickness. If you were to use a uniformly thick spiling batten for the sheerstrake, and make the sheerstrake to the spiled shape, it would not fit. Maynard Bray’s book How to Build the Haven 12 1/2 Footer provides a spiling method that allows for the sheerstrake’s nonuniform cross section: use a spiling batten of nonuniform cross section approximating the sheerstrake’s molded shape. Specifically, one makes a batten from two pieces, one thin and wide and the other thicker and narrower and placed where the thicker part of the actual sheerstrake is.
I decided to first place the thin, wide spiling batten in place on the construction molds, then bend the 5/16 x 3/4″ piece into place onto the wide spiling batten. With the two pieces in place on the construction molds, I fastened them together with screws, placed near each of the station molds. Then I proceeded to use my dividers and mark the spiling batten for the sheerstrake width at each station.
I made a special spiling board for determining the shape of the sheerstrake. I added a piece of fir about 5/16 x 3/4″ in cross section, positioned about where the thickest part of the sheerstrake would be, to a wide 1/8″ thick piece of cedar.
Because I bent both pieces of the spiling batten into place before fastening them together, I built in some residual bending stresses. When I removed the batten from the molds, it came off with a significant bend and some twist.
After removing the sheerstrake spiling board, it had a significant curve due to uneven bending stresses in the two pieces.
I proceeded to clamp the spiling batten down flat onto my planking stock, then transfer the marks representing the plank widths at each station. I was not 100% confident this method would work, so I first made a “test” sheerstrake from a piece of cedar. This involved cutting out the spiled shape from a 1″ thick piece of cedar, then planing away enough of the plank to give it a good approximation of the molded sheerstrake’s shape.
I’ve clamped the spiling board down flat onto a piece of cedar, from which I’ll make a test piece of sheerstrake to verify that my spiling method will work.
When the test sheerstrake was clamped in place on the molds it fit extremely well, so I was confident that using my spiling on mahogany planks would give me sheerstrakes that would fit.
I wasn’t sure my spiling would be accurate, so I made my first attempt at a molded plank from a piece of cedar rather than to risk ruining a piece of mahogany. The cedar test plank fit very well, so I proceeded to use my spiling to lay out the mahogany planks.
Justine has 12 cedar planks on each side of the hull. Planks are hung sequentially from the garboard to the sheerstrake. Justine’s sheerstrake is effectively a large mahogany molding and making it is an involved process that I’ll treat in a separate post. The previous post described how I spiled the planks and illustrated fitting and fastening the garboards.
In theory, hulls are symmetrical about the boat’s centerline. Justine was my first attempt at building a carvel planked boat, and I was pleasantly surprised to find only relatively minor departures from symmetry between port and starboard halves of the hull.
In planking, symmetry is your friend. You can line off only one side of the hull, and do the spiling on that side, get out a plank for that side, and make a mirror image of the plank and fit it to the opposite side of the hull. I noticed only small imperfections in the fit of the mirror image planks, and I corrected them with judicious use of a hand plane. By fitting a complete course of planking, port and starboard, before starting the next course, you are less likely to build in distortions to the hull’s shape.
Next I’ll describe a few things that arise as the planking proceeds.
Staggering butt blocks
All 12 courses of Justine’s cedar planking have butt blocks. Although butt blocks are designed to be very strong and secure, they aren’t as secure as continuous, uninterrupted planks. So it’s important to stagger the butt blocks so that you don’t have a sizable area where the hull is somewhat weakened. There is a rule of thumb in carvel planking that one can follow to suitably scatter the butt blocks: (1) In adjacent planks, there should be at least two frame spaces between butt blocks; and (2) there should be at least two planks separating butt blocks that occupy the same frame space.
Not all joints where the butt blocks are placed are visible in this photo, but you can get an idea of how they are distributed about the hull.
Backing out a plank
In most places on the hull, Justine’s frames are curved. The planks lie more or less perpendicular to the frames, and the inside surface of each plank must fit snuggly against the frames. So most of the planks need to be hollowed out slightly, or backed out, so that they will fit well on the inside of the hull where the frames are.
Backing out is done with a hand plane that has a curved iron and a curved sole. I made my own backing-out plane for this purpose using some live oak off-cuts from when I cut out my floors.
My backing-out plane, tilted on its side to show the curvature of the plane’s sole.
I used a standard templating tool to record the convex shape of the frame, and then used that as a guide to how much backing out was needed at each station.
A plank that has been backed out. The templating tool gives a sense of the curvature at this particular location on the plank. The plane in the photo is not my backing-out plane.
After using the backing-out plane, I lightly sanded the inside surface of the planks but I wasn’t really fussy about eliminating all the planing marks.
One additional note about backing out: the resulting backed-out plank needs to be 5/8″ thick over its complete width after the outside surface is faired, so if a plank needs to be backed out, it must start out thicker than the nominal 5/8″ thickness of the planking. I kept all my planking stock rough sawn until I’d selected a particular piece to use in a particular location on the hull. Once I knew where the piece would be used, I decided how much to plane off. After reducing the thickness, I marked it with the spiled shape. After cutting out the plank’s shape, I did the backing out.
Plank edge bevels
Justine’s plank seams will be caulked with cotton to help make them watertight. Suitable space for the caulking must be left between the plank edges and at butt joints, in the form of a caulking bevel.
I did my best to get adjacent courses of planking to butt against each other, edge-to-edge, as I fit and prepared them for fastening. Then I planed a small caulking bevel along the edge of the new plank I was about to hang, on the edge where it would abut the previously fitted plank. The caulking bevel extended from the outside of the plank to about 2/3 the distance to the inside of the plank (about 7/16″ in this case), and so that there would be a gap of about 1/16″ at the outside of the planking. Before fastening the plank, I put a coat of red lead on both edges of the plank.
Use of leverage
I did most of the planking working by myself. Occasionally I had to come up with alternatives to having another set of hands. A good example was fitting and fastening the last cedar plank at Justine’s transom, where the plank requires a significant twist as it goes aft.
My “third hand” took the form of a wooden hand screw fastened to the plank, then using a line to the barn ceiling to apply sufficient torque to the plank to bring it into contact with the transom. A rolling hitch (which I learned as a “taught-line hitch” in Boy Scouts) came in handy to properly adjust the tension in the line.
On occasion, a “third hand” was needed to get a plank into position for fitting, drilling for fasteners, and fastening. A method that worked well aft was to use a hand screw applied to a plank that had extra length, then use a line to apply torque to bring the plank into position against the transom.Uppermost plank after fastening and trimming off most of the excess. Note that I used plywood panels to protect the transom during much of the building process.
Fairing the planks
At this point Justine’s hull has 12 cedar planks on each side. They have been backed out on the inside, but so far the outside of each plank is still flat. Thus, from the outside, the planking is facetted and only approximates a smoothly curved, fair shape.
Fairing the hull is not simple. It needs to be approached slowly and deliberately if you are doing it for the first time. I started with an 03 smoothing plane that was very sharp and set for a very fine cut. I mostly planed diagonally, across several planks. You have to be careful to plane with the grain of the planks, and frequently the grain changes direction so you have to be careful. Places where you have drilled out knots are also difficult because the direction of the grain can change abruptly. It’s impossible not to have a bit of pieces of wood chipping out.
Battens are useful for finding high spots that need planing off, so are you hands: simply stroking a hand along the planking is a good way to detect irregularities. When the hull is fair, at any point on its surface you should be able to lay a batten, in any orientation, and it should lie right on the hull with no gaps.
I finished fairing using a long piece of thin plywood to which I’d affixed handles on the top surface and sandpaper to the bottom. Scot calls this tool an “agony board.” I didn’t use this so much to fair the hull, as to simply remove planing marks once I’d come close to fair-ness with my plane.
As you are fairing the hull, inevitably you reduce the plank thickness to the point where you are about to plane into one of the silicon bronze fasteners. So you have to back out the fastener, counterbore a little deeper, and reinstall the fastener.
Once you’ve done your best fairing the hull, you need to fill any chipped out grain, as well as over all the fasteners—and there in excess of 1000 silicon bronze flat-head screws that secure the cedar planks! I used “Bondo” over the fasteners as I thought it would be easier to dig out than epoxy and microbaloons, if the planks ever need to be refastened. This occupied several day’s work, filling, sanding, and perhaps refilling and sanding. Fortunately my son Micah helped me with this phase of the project.
Caulking
Cotton caulking comes tolled up, somewhat like a skein of yarn. Unlike yarn, it is not twisted but it is formed into a long strand about 1/2″ in diameter. A strand can be divided if less material is needed to fill the seam which was always the case for Justine.
Cotton caulking is a bit like yarn, but not twisted. It can be divided to make thinner strands of material.
I’d never caulked a seam before building Justine. Two excellent articles on the subject have appeared in WoodenBoat magazine, and I followed the advice of author Harry Bryan very closely. The first, “Caulking Small Boats: Part I. Tools for the Job.” WoodenBoat, Vol. 201, p. 33 , taught me that the best tool by far to use for caulking is a roller that is easily made. I also forged my own caulking iron and made a caulking mallet following a design by Joel White (a drawing appears in Harry Bryan’s article).
The quickest method for caulking is to roll it into the seam with a tool like the one on the top. A caulking iron, below, is essential in tight spaces. Mine has a radius of about 1/32″ on the edge.I love Joel White’s mallet design. Mine has a curly sugar maple head and a black locust handle.
I also closely followed Harry Bryan’s advice in his followup article “Caulking Small Boats: Part II. Putting the Tools to Work.” WoodenBoat, Vol. 202, p. 25. It took several seams to get the hang of it, but after that it moved along nicely.
I’ve come to the end of a strand of caulking and will lightly twist another piece about 4′ long onto this one, then continue to roll it in. This photo allows you to compare a caulked seam with an uncalled one.A completed section of caulking, including a butt between planks. Plank fasteners have been filled with Bondo and sanded smooth.
Once all the seams are caulked, they are payed. This involves applying thinned paint to the caulking to help waterproof its exterior surface, rather than to saturate it entirely. That way, if water does get in, the raw cotton will swell and seal the seam. Again, I followed the information in Harry Bryan’s articles to pay the seams.
The final step to finishing the plank seams is to apply seam compound over the payed caulking. This produces a surface over the caulking that is flush with the plank surfaces and also helps waterproof the seams. I’ve been warned that once Justine goes in the water, the planks will swell, and some of the seam compound will be forced out and need to be smoothed off when repainting the hull.
Every plank’s shape is determined through the process known as spiling. A long, thin piece of wood, narrower than the plank to be gotten out, is clamped in place on the construction molds. It is positioned between the adjacent plank (or keel, in the case of the garboard) and the pencil lines that mark where the new plank’s other edge will be. I had several pieces of cedar that I’d planed to about 1/8″ thick that I used repeatedly as spiling battens. I sometimes used strips of 1/4″ plywood to make up segments of a spiling batten.
I’ve clamped the spiling batten in place where Justine’s third plank on her port side will lie. The spiling batten is narrower than the resulting plank will be, but it is shaped so that when clamped down, it will follow any curve the plank needs to take. I made my spiling batten up from several shorter pieces, joining them with thin pieces of wood, well fastened with several very short screws. By using several pieces to make the spiling batten, I could make slight “dog legs” at the joints so as to follow the curve the new plank would need to take.
Spiling is a clever technique that involves placing marks on the spiling batten that can be transferred onto the planking stock to give the plank’s true shape. Because the spiling batten is thin, it can be bent and twisted so that it lies in place against the frames, then when the batten is unclamped and laid flat, it can be used to mark the planking stock while it is flat. This assures that when cut out and bent into place on the frames, the new plank will fit quite well.
With the spiling batten clamped in place, a pair of dividers is set at a suitable distance (here about 1″) and maintained at that distance for the remainder of the spiling process. I’ve put one leg on the edge of the adjacent plank, then I’ll mark the position of the other leg on the spiling batten.The dividers are repositioned so that one leg rests on the pencil line (made during lining off, not easy to see in this photo but more visible in the previous one) indicating where the new plank’s edge will be. Then a mark is made on the spiling batten where the divider’s other leg falls.The batten now has two points marked. The upper one, marked “K,” is for the edge of the plank that will be closest to the keel, and the lower one, marked “S,” is the edge closest to the sheerstrake. Note also that I’ve put a line on the batten indicating the location and orientation of the station at which the marks have been made.
I marked the spiling batten with “K” and “S” points at every station. Once that’s done, the spiling batten is unclamped and placed on a suitable piece of planking stock.
The spiling batten has been laid on a suitable piece of planking stock, and is held in place with spring clamps. On this particular spiling, I had made a pattern piece that closely fit the shape of the stem rabbet and attached that to the forward end of the spiling batten while it was still in place on the construction molds.With the spiling batten in position, all of the station lines and “K” and “S” points can be transferred to their appropriate positions on the planking stock.I’ve removed the spiling batten, and clamped a batten along the line of “K” points that define the edge of the plank closest to the keel. Then I used a pencil to mark that line on the stock. I also marked the shape where the plank will lie in the stem rabbet by tracing along the edge of the piece I’d added to the spiling batten. Once the “S” points are similarly connected with a smooth curve, the plank can be cut out.After fine-tuning the plank’s shape, the plank is fastened to the frames and along the stem rabbet.
All this may sound complicated and like a lot of work. But you have to do enough of it that you eventually get pretty good at it.
Justine’s first plank to be “hung” is the one nearest the keel, and planking proceeds working toward the sheerstrake. Because Justine is being built upside-down at this stage, the planking proceeds from top to bottom on the construction molds.
The plank closest to the keel is called the garboard. The frames in this part of the hull are hardly curved at all, so the garboard does not need to be “backed out” on what will be its inside surface. There will be a significant amount of twist in the garboard, but this can be achieved with clamps before the garboard is fastened.
Justine’s planking is northern white cedar, harvested in Maine. My supplier was Bruce Tweedie at Tweedie Lumber in Thorndike, Maine. I purchased about 600 board feet of live-edge planks, rough-sawn to approximately 1″ thick. (One board foot is a volume of lumber that is 1 square foot in area and 1″ thick.)
Bruce Tweedie delivered my planking stock. 600 board feet was more than enough for Justine’s planking.
My planking stock took a variety of shapes, reflecting the shapes of the logs from which they were cut. If the log was from the base of the tree, its end was significantly flared. Only a relatively small fraction of the boards was straight; most were gently curved, which was fine as most of the planks had gently curved shapes. A few of the planks even had reverse curves, giving them an “S” shape. Most of the planks were between 10′ and 13′ in length.
I stored my planks upstairs in the barn, sorting them into two piles. One was for planks that were nearly straight, the other was for planks that were curved. Here you see the curved pile.
It’s the rare cedar plank that is free of knots. The knots in my planks rarely reached more than 3/4″ in diameter, but many of them were loose and after planing the boards to the required thickness, I used a forstner drill bit to drill them out, drilling about halfway through the board from one side, then filling the resulting blind holes with cedar bungs that I glued in with a mixture of epoxy and microballoons. (The microballoons are tiny hollow latex spheres that serve to thicken the epoxy and also make it much easier to sand.) After one side was bunged, I flipped the board over and drilled and bunged the knots on that side. Once the epoxy had dried, I cut the bungs flush with the plank surface using a sharp chisel and block plane.
This plank has quite a few 3/4″ bungs installed. There are still a few knots in the foreground, but these are small, tight knots that can be left undisturbed. I haven’t yet trimmed the bungs flush to the plank surface.
The process of determining the shape of a plank before it is cut out is called spiling. I’ll describe spiling in a later post. With the plank’s shape determined, you can go to the pile of planking stock and select a piece that can be used without a lot of waste.
The garboard’s shape has been marked on a suitable piece of planking stock, and it’s been cut out using my circular saw.
A plank cut to the shape given by the spiling will be a close fit, but still need some trimming to result in a tight seam with the adjacent plank (or with the keel and stem, in the case of the garboard). It’s an iterative process of clamping the plank in place, marking the places where material needs to be removed, unclamping the plank, planing off the excess, and repeating as necessary. Once you’re satisfied with the fit, the plank is close to being ready to fasten.
Before fastening a plank the mating surfaces on both the frames and the plank are given a coat of red lead paint. It’s the only opportunity to get any paint in those joints.
Justine’s planks are 5/8″ thick, and the frames to which they are fastened are 7/8″ square in cross section, giving a total of 1 1/2″ of material in which to drive a fastener. I chose to use #9 x 1 1/4″ silicon bronze screws for nearly all of the plank fasteners. The screws need a pilot hole for their entire depth; a clearance hole for the screw’s shank in the plank itself, and a counterbore at the surface so that when tightened the head of the screw will lie slightly below the plank surface. (Once the hull is planked and smoothed, the screw heads will be covered over with a filler material. I used “Bondo.”)
The garboard is fastened to the frames with silicon bronze flat-head wood screws. Two screws secure the plank at each frame. Note the pronounced twist in the garboard once it’s fastened in place.
Because none of my planking stock was longer than 14′, every one of Justine’s planks needed to be made up of two pieces to cover the distance from stem to stern. So to complete the garboard, a second piece of planking needed to be fitted that would extend back to the transom. The two pieces are butted against each other where they come into contact.
To reinforce the butt joint, it is backed up by a separate piece called a butt block. I made all my butt blocks from pieces of live oak. The butt blocks are 7/8″ thick and they extend about 4″ on either side of the butt joint. They also overlap the adjacent course(s) of planking. Once shaped, the butt block is clamped in place and holes are drilled for fastening it in place.
The port garboard butt block ready to bed and fasten.
Before fastening a butt block, the mating surfaces are given a coat of red lead, and a coat of a putty-like material called bedding compound is applied that will help seal the joint yet remain pliable.
The butt block is coated with bedding compound before being set in place. Excess bedding compound gets squeezed out once the six fasteners are driven home.Six fasteners do a good job of drawing the plank ends tightly in place so that the plank adopts a curved shape, even close to the joint. The butt block is wider than the plank so that the next plank can also be bedded to it, furtheer ensuring that the joint will be watertight. When the hull is finally right-side up, the curved edge of the butt block will be able to drain any water that might find its way there.The garboard is in place from Justine’s stem to the transom. The butt block is between the second and third frames from the right.
With the port and starboard garboards in place, “only” 24 planks remain to be gotten out and hung…
