Bottoms Up!

It was with some anticipation that we launched into planking the bottom as we would now be able to use those amazing clear fir boards that we had bought on Kijiji back in April. This was quite possibly the buy of the century. The ad read, “Clear Douglas Fir 3/4"x3'"x5' 0.10/linear foot Lumber” (~$0.50 per board foot). The material was off-cuts from a siding job and although the actual widths of the boards varied between 2-3.5” it was absolutely clear, straight grained, old growth fir. What a coup!

At first the prospect of planking seemed quite straight forward, joint the two edges of each board dead flat, apply a thin bead of Sikaflex, clamp the over hanging ends of each board securely to the previous plank until the fit is tight, counter bore a screw hole through the plank and into the chine, and then drive home a 1 ¼” stainless steel screw. Repeat until you reach the front of the boat, then cut off the overhanging pieces flush to the garboard plank.

Of course we agonized over planning a slight angle on each plank so that we would get a slight “v” between each set of planks. We understand that on many traditional boats this is standard practice and that these “v” joints would subsequently be chinked with cotton. But in the end we decided that a modern sealant like Sikaflex should provide similar performance characteristics to the old world methods, plus it would be a lot easier to implement.

We started at the transom and worked our way forward. The first plank was really easy, just line it up parallel to the transom and screw it down all the way around. The work progressed quite quickly for the first couple of feet until we encountered our first challenge—clamping the boards together. As we approached the 2 foot mark we realized that our 2 foot quick grip clamps would soon on longer be long enough to clamp the board together. You are probably thinking, “just get longer clamps”, and while that would an acceptable solution for a while it would not be a fix all as our longest clamp is 6’. Instead, we started to stagger the amount of overlap from side to side so that we would always have a point of purchase on each side. Although there were a few occasions where we ended up drilling a hole in the overhanging plank so we could get a clamp in place.

On the first day we decided to plank approximately 5 feet and then to put a couple of clamps on the whole set up to draw it up nice and tight as there were a few small gaps starting to form in the middle of the planks. To address any up/down crown or sagging in the planks we initially put light pressure on the clamps and then carefully knocked individual planks up/down until the whole area was generally quite flat. We left the clamps in place for several days to allow the Sika to set before proceeding with any further.

The next 5 feet were straight forward as we had established a good routine that quickly allowed us to put the bottom planks on. In fact we spent more time prepping the boards and selecting which boards would go where than actually installing them. We did come up with a good trick for clamping the next 5 feet set up together to close any small gaps that may have formed. We clamped a couple of 2x4’s to our molds that had a groove cut in it the exact size of the end of our quick clamps. Then by reversing our clamps to make them into spreaders we fit the other end into another small groove that we cut into our caul. The picture is worth a thousand words….

As you can see from the photos we trimmed the overlap excess in between the 2nd and 3rd sections of planking and started the process of hand planning the bottom to a smooth finish while the Sika set. The sides were first roughly cut off with a circular saw (being very careful!) and then fine tuned with a block plane. This was slow and arduous work slicing through end grain—again a sharp plane is invaluable for this type of work. The last plank was interesting, it was cut to fit snuggly against the stem and was generously slathered with Sika to prevent water penetration before it was forced in with a mallet. This effectively closed up any possible gaps that may have existed between the middles of the last section of planking.

We were extremely pleased with the final appearance of the bottom and were paid the highest of compliments when someone asked if the bottom was a single piece of wood.

With the bottom all done it was time to build the skeg—the sternward extension of the keel. The plans called for a piece of 7/8” softwood but now that we have it made I am considering building another out of hardwood as I am concerned about the durability of the softwood version. It was a little tricky to get the same curve on the bottom of the skeg as the bottom of the boat but after a little trial and error we managed a good fit. We elected to wait to install the skeg and the two bottom rub rails until after the bottom is painted. Hopefully, this will result a better layer of water protection than a bare wood to wood joint.

You can really see the curve in the bottom of the boat

After a couple of days of letting the Sika dry on the last set of planks we were eager to turn the boat over so one night just after we returned from being out we gathered the family together—the four of us. The two boys took the stem and I lifted the stern. Straight up at first to clear the molds and then we slowly started to rotate the boat until it was right side up. About half way through my bad shoulder went crazy and it felt like I had dislocated it. As it turned out I was okay after about half an hour but, did it ever hurt at the time! Now we really had a sense that we are building a boat. We also incredibly taken by how big the boat seemed.

Joe Lapstrake

The Procession of The Strakes

After completing all of the preparatory work, we finally had the opportunity to begin the process of planking the craft. Although, on most craft, the garboard is inherently difficult to shape and attach because of the tight curves that it must accept, Willy’s first planks were a simple matter. This can be largely attributed to the flat-bottomed construction of the hull, not our boatbuilding prowess. However, after completing these strakes, we were faced with a new challenge. Unlike the bottom boards, which are affixed to the chine using screws, the remainder of the planks (8 in total) are fastened to the previous strake with copper rivets. Being a non-ferrous metal, copper is fairly inert in moist environments, which makes it an ideal candidate for this application. Spaced at 3½-inch intervals along each lap, we had a total of almost 400 rivets to install over the entire craft. Needless to say, we were somewhat daunted by this prospect. Fortunately, although this process does require the builder to develop a certain rhythm, it is, in reality, quite simple. The most important resources in this procedure are a willing assistant and a surplus of time, as it can be rather lengthy. Below, the system is condensed into five steps. Please recognize that, while this is a brief overview of the process, more detailed information concerning this method is outlined in many boatbuilding books.


1. Bore a slightly undersized hole in the hull at the intended location of the rivet. After the nail is inserted, this will create compressive forces on the wood that effectively seal the joint from water penetration.

2. Counterbore the hole on the outer face of the board to the dimensions of the nail head. Although this step is not necessary, it helps to seat the nails flush to the hull without scarring nearby wood through overzealous use of the hammer. In addition, we also found that some of our mahogany planks so hard that it would have been very difficult to sink the nail heads without counterboring them. If you are have softwood planking this step may not be necessary.

3. Drive the nail ¾ of its length into the pre-drilled hole. At this point, the assistant places the rove (in the rivet punch) on the opposite side of the plank. Proceed to drive the nail until level with the exterior surface of the hull. By this point, the rove should be snug to the plank’s interior. However, if this is not the case, a few taps on the punch with a hammer will remedy the situation.

4. Cut the protruding nail off, leaving it about 1/8” proud of the apex of the conical rove. While the exterior individual braces the nail head, peen the excess metal into an even, symmetrical dome, preventing the nail from retracting the future.

5. Repeat 399 times.

Although riveting is somewhat time-consuming, mundane work, if both workers are able to develop a sense of cadence, it is possible to affix a strake in little over an hour.

Close up of exterior hull rivets

Seeing as the process used for each subsequent plank is identical to the system outlined above, it would seem overly repetitive to give a detailed account of each strake. Instead, we have consolidated this task into a series of photographs, allowing the reader to witness the accomplishment of hours of our labour in a convenient photographic form.

One strake per side



Two strakes per side

Three strakes per side

Three pictures of four strakes

Done - Five strakes


Now that all of the constituent elements of the hull sides are completed, the next item on our agenda is that of bottom planking. Seeing that Willy is of flat-bottomed, cross-planked construction, we anticipate that this will be a fairly straightforward task. Tune in for the next installment soon!

Joe Lap

Preparing The Strakes

After obtaining the strake shape, it is important to scribe the hood (forward) ends of the strakes to mimic the curve present in the stem rabbet. Ideally, the planks should converge neatly with the stem, without any gaps or differences in level. Although this is a simple concept, the builder must be careful to attain an accurate profile on the strake, as any discrepancies between the two components will become obvious later on. To shape these ends, we used the circular saw to make initial cuts and finalized the shape with a block plane, much like the process used on the strake edges. As is often the case, blade sharpness is essential here. Although a keen plane blade will make short work of the task, this step can be very frustrating if one is forced to contend with a dull blade. Because our strakes are mahogany, it was necessary to redress the blade several times during the process of forming all ten strakes. When this is complete, each plank must have “gains” cut into the ends. Usually about 14 inches in length and identical in width to the lap, these long, tapering rabbets effectively remove 50% of the board’s thickness at the stem and stern.

When two gains mate at a lap, the result is a smooth transition from lapstrake to carvel-type planking at both ends of the hull. This allows the builder to form a watertight seal at the transom without going to the effort of coping the stern to accept the laps. Traditionally, this task would be completed with a rabbet plane. However, in the interest of efficiency and accuracy, we opted to design a gain jig for the router. Although it was a highly effective device, we found that it was still necessary to use the hand plane to fine-tune the gains, as, in reality, they must be cut on a slight curve, something that the jig could not provide. For this step, test fitting of the gains on the craft is essential to forming tight joints between the strakes. However, if the task is completed with care to detail, the effect formed by the laps swooping upwards as they taper away at each end of the craft is striking.

Simple inclined plane rabbet jig

Jig in action with router

Once satisfied with all aspects of the first two planks, we finally had the opportunity to begin attaching the strakes to the frame. At this stage, we were eager to begin the true “construction” of the craft, but still had some misgivings about the process. However, although this seemed to be a rather daunting task, it was, in reality, surprisingly simple. At both stem and stern, we secured the planks with 1¼” 316 stainless steel screws, which are purported to have superb corrosion resistance. The same screws were used to secure the garboard to the oak chine. It is truly at this stage that all of the effort exerted during the spiling becomes worthwhile. Because we were able to determine the proper strake shape earlier, we found that each plank readily conformed to the contours of the hull. If a builder neglects the task of spiling, however, he will find that a great amount of force is needed to coax the boards into their proper locations. Stern view of rabbets

Although, by this point in time, we were eager to begin placing the strakes on the strongback, we had to address one final concern—how to seal our craft. In an ideal world, all joints would be perfectly seated against each other, eliminating the need for any sort of bedding compound. However, unless a builder is incredibly skilled and highly accurate, it is inevitable that a boat will have some voids in the joints. This issue can be addressed through two primary means. In traditional lapstrake construction, joints are caulked with textile fibres, such as jute, hemp, or cotton. This system acted upon a simple principle: all of these fibre types swell dramatically when in contact with water. In this way, a craft will “self-seal” due to the expansion of the caulking in its joints. Some builders also believe that this method helps to create pressure within the laps, which subsequently adds some rigidity to the hull. However, there is one major drawback to this approach: the boat will not seal immediately. As a general rule, the craft must be immersed in water for several hours before it will become watertight. In the context of our Willy Winship, a dry-storage daysailer, this means that we would be forced to pre-wet our boat before each sailing session in order to ensure a dry hull. Not only would this be inconvienient, but the retention of water in the caulk during storage would promote the growth of mold and fungi. Fortunately for us, the advent of 21st century technology brought myriad new marine sealants to the marketplace. Builders can now choose from a wide range of polyurethanes, polysulfides, and other petrochemical products that can be handled much like ordinary silicon caulk (note: never mention silicon caulk in the context of a boat, as most builders are vehemently opposed to this material. It is worthwhile to invest the extra $ in a marine sealant, if only to avoid the disapproving looks from other builders). Although some of these products, like 3m 5200, act as both an adhesive and a sealant, the general consensus among the masses is that bedding compounds should have very low adhesive properties and high elasticities in order to allow the wood to move on its own accord. After processing the overwhelming number of opinions that surround this topic (a task unto itself), we finally concluded that we would use Sikaflex 291 on all wood-to-wood joints around the craft. Being an all-purpose, low-strength marine sealant, Sikaflex has the durability and watertight characteristics of a synthetic caulk and the ability to allow wood to undergo seasonal changes unimpeded.

The only drawback to this compound is that it may draw disapproving glances from the devout traditionalists. Fortunately, seeing as the Sika is concealed by the joints, the boat, when finished, will be nearly indistinguishable from a cottoned craft—except, of course, for the fact that Willy, unlike the ships of old, will be reliably watertight.

Joe Lap

COMING SOON: THE PROCESSION OF THE STRAKES

The Formation of a Hull

It is a pleasure to be able to blog again! As has been the case many other times, recent building activity has conflicted with our ability to keep our readers updated. However, although our blog was silent, the boatshed was abuzz with activity. I am pleased to report that we have made significant headway since the previous post. As shown below, we have completed the side planking and have begun the process of laying the flat bottom. After our most recent efforts, our project is truly starting to take on the likeness of a ship. After such a significant lapse in reporting, it is probably most appropriate to recount the month of June in chronological order. Because the last post detailed the installation of the transom onto the strongback, the last step before planking, it seems appropriate to begin with the garboard.



When constructing a lapstrake craft, the boards (strakes) overlap each other, much like the shingles of a house. Besides aesthetic appeal, the advantages of this system are twofold. Firstly, the overlapping areas are doubly thick, meaning that they act much like stabilizing stringers running from stem to stern. Because of this, it is possible to create a clinker craft using relatively light material. In addition to adding strength, lapstrake construction also aids in maintaining a dry interior, as the ridges on the outside of the hull serve to direct spray downwards. When sailing in adverse or cool conditions, this is incredibly valuable! Because of the craft’s design, The bottom board, or garboard, is the first plank to be laid, as it is the base on which all of the other strakes will rest. In all boatbuilding books, authors seem to regard the garboard as a formidable challenge. This is primarily because, on round-bilged boats, the first strake must accommodate for the compound curve present at the lower extent of the hull. However, because Willy Winship is a flat-bottomed craft, we were able to avoid many of the issues that generally plague the garboard. Still, we were faced with the difficulty of deriving the correct plank profile in order to minimize stresses exerted on the strake during assembly and use. Although it may appear that a correctly-spiled craft has planks that are slightly curved, or scimitar-shaped, in reality, strakes can be incredibly odd. For example, the sheer on this boat had to be distinctly “s” shaped in order to take the contours of the hull. Thus, it is important to devise a process through which the proper plank form can be determined. When faced with this challenge, the amateur boatbuilder may be tempted to panic, as some experts tout methods that entail the use of several spiling battens, dividers, and transfer marks. Fortunately, there is a simple method of establishing strake shape, sometimes called the “truss method”, consisting of three straightforward steps:

1. After obtaining two flexible, true battens the width of the laps in question (Plywood seems to be the ideal material for this application, as it is not subject to the natural stresses found in natural woods), clamp one to the previous lap, or, in the case of the garboard, to the chine or keel.

2. The second batten should be affixed to the molds at the positions predetermined through spiling the hull. It is important to remember to place the batten with the top edge aligned with the mark, as the width of the batten represents an area that will be covered by the following strake

3. Using a few dozen short scraps of batten material, attach cross braces in a triangular fashion akin to that employed in truss bridges. This will result in the formation of a rigid replica of the plank that can be used to transfer the correct shape to the waiting board.

Okay, enough theory....here is what really happened:
 
1. We took one of our scrap planks that we made while we were practising scarfing and bent it around the molds and marked the chine and battens on the inside with pencil lines. We cut the plank to the lines and put it back on the molds. A total failure--it needed about 6" of edge setting to get it to lie properly on the molds.

2. Having already been burned once we were too chicken to just jump straight into cutting a valuable plank so we decided to cut up a piece of plywood first to see if we could put the theory into practise. Here is our first truss.

3. Laying out the truss on the plywood.

4 . Plywood plank being fitted to the boat. Success!

5. Transferring to the mahogany plank.

By using this process, we found that it was possible to obtain board form quickly. After reviewing the lines on the completed craft, we concluded that they closely followed the initial spiling batten locations that we had deemed to be fair earlier—the objective of any spiling technique. No aspect of this method is difficult to master, and, as such, it is ideal for any first-time builder. Despite its simplicity, however, the accuracy of the above system rivals any of the other spiling methods presented by experts.

6. Lines on the plank, ready to be cut to shape.

7. Planning to the line after rough cutting with the circular saw.

After transferring the proper dimensions of the plank to the scarfed boards using the assembled truss, it was relatively easy to shape the strakes. In most books, authors recommend using a circular saw for this step, as most planks have too much curve to be cut using a tablesaw. Initially, we were somewhat apprehensive about this prospect, as, for us, the circular saw has been a tool usually reserved for basic cuts requiring little accuracy, or for jobsite construction. It seemed to have no application in the fine craft of boatbuilding. However, having now cut ten boards with this tool, we can attest to the fact that it is effective in this use. By using the saw for rough cuts and reaching our final shape using the hand plane, we were able to combine accuracy and efficiency. Although the saw was useful for this task, we were reminded of the sheer versatility of the hand plane. Although it appears a simple tool, we have reached for the plane countless times for tasks no other tool could do in the construction of Willy. From leveling the chines to squaring the planks at the transom, our two planes have been indispensable in this undertaking. In addition, they are a sheer joy to use! There is something about the rhythmic motion and the whisper of the blade in use that has an entirely unique sensation. Unlike with power tools, where all senses are obscured by the incessant vibration and din of the motor, the user is able to wield a plane purely through feel. Although one could write extensively upon this topic (and that shall probably come), it will suffice to say that any shop that lacks planes is inadequately equipped. 

8. Hood end cut to shape (trial and error to fit) and the gain cut.

9. First plank in place and the spiling battens positioned and ready for the truss webs to be added.

 

 

 

 

A Hunk of Mahogany -- AKA the Transom

Finally, time to blog—this weeks exciting episode is about the transom. Our transom started life as a piece of rough sawn 4/4 African Mahogany 10” wide and 16’ long. After planning our board was reduced to ~7/8” and was cut into 2 pieces each about 44” long. The two pieces were then matched together to get the best looking grain with the hope that it would look like a single board once we glued it up.


The process we used is as follows:

• Joint the edges of the two boards

• Position and use the router to place 4 biscuits (extra strength)

• Dry fit to ensure that everything is right (expand the size of a couple biscuit slots because they are too small)

• Mix and apply epoxy

• Slather biscuits with epoxy and slide them into one side of the board

• Apply epoxy to the rest of the board edge

• Push the boards together and gently lay them down on the top of the table saw (with wax paper under the joint)

• Clamp the boards to each other and also down to the table saw top (nice and flat)

• Wait

Once the epoxy was dry we unclamped it and had the good fortune to take it to my son’s shop class to run it through a brand new General thickness sander. Tam, if you are following along on our blog, thanks again for this kindness, it really saved us a bunch of time and the end result was far superior to anything we could have done with our tools.

Here is a picture of the end product. Can you see the line? Or is it one board?

Now the real fun gets started. Willy calls for a top curve on the transom, but the plans do not show the radius of this curve only that the center will be 2” higher than the side height. Scaling the curve of the plans showed a radius of 84” so I knew that a large trammel would be in order. Working with scrap pieces of plywood for the trammel I gradually worked my way up to a radius of ~120” before the center was 2 ¼” higher than the middle and that is where I decided to stop the madness.

Hereare the pictures of the trammel jig for my router.

I cut a pattern in a piece of MDF and then used that to cut the actual transom. I decided that the two step method was safer than directly cutting the transom on the trammel since I do not have enough mahogany to make another transom with should I accidentally wreck this one.

The transom is a complex board with many angles that have to be cut.  On Willy the transom is slightly angled backwards from the stem of the boat and of course it is significantly wider at the top than the bottom.  All of which means that the sides of the transom are complex angles (up and down--height,  and front to back--thickness).  To determine these angle we went back to the lofted plan to determine the side angles and to the plans to get the front to back angle. 

Using the table saw the blade was set at the correct angle 10 degrees, and the transom was held down on the sliding table at an angle.  Lots of care needs to be taken at this step or you will end up with one of the beveled angles going the wrong way.  I wish I had taken a picture at this stage to help you visualize.

Cut the board without problems and then trial fit it to the boat.  It was clear that the front to back angle was wrong, thankfully we could just remove more material.  So back to the table saw, change the angle ( a bit of a guess now) and re-cut.  Whew, it all worked out.

Lots of steps to get to this point but it was nice to finish up and to screw the transom to the chines on the boat. Next up planking.

Lining Off

With the stem in place and a full head of steam, we are excited to be thinking about moving into the planking. But first, we have to line off the boat…a job that everyone says is more feel than science.

Willy calls for five planks and although they are drawn onto the plan on the front page we realize upon inspection that the lines shown have no reference to reality. We think that the planks will look best if they appear to all be about the same size. For the middle planks that will be no problem. But the garboard and sheer strake planks present their own issues. Optically the garboard plank will include the thickness of the flooring, so this plank needs to be a little smaller than the others to appear the same size. Whereas the sheer strake plank will be partially covered by the outwale so this plank needs to be a little bigger than the middle ones.

So there you have the theory, in reality we ended up making all the middle planks the same width, the garboard about ½” smaller and the sheer strake about ¼” bigger. As it turned out our planks are not wide enough to accommodate a sheer any wider so we compromised.

We had real problems with getting good battens for the lining out. At first we ripped up a spruce 2 x 4 in to 3/8” strips and even though the board was straight to start out with it had some incredible internal forces that warped these thin strip something fierce. For stability we decided to use plywood. The 3/8” ply was ripped into ¾” wide strips (the width of our overlap) and scarfed together to make 16’ battens. We encountered some difficulties with battens where there was a gap in the 3 ply, plywood—this was solved quickly by brad nailing a section of reinforcing plywood over the bad piece. It was amazing how visual this task really is, there is lots of looking at the battens from different angles in order to determine what a “fair line” really is. Here is was we have decided to run with:

Oh, and did I mention that we needed to plane off the chines before lining off?  Probably not so here is a short of that process using old fashioned hand tools--a delightful job actually until you get right up tight to the stem where the whole process gets a little more trying.  Simply plane until a board laid across the chines lies flat on both chines.  Here is junior at work:

Our planks were purchased off a Kijiji listing for “magogany boards”. The mahogany boards are approximately 8’ long and 5 ½” wide and were used to panel a rec room for the past 20 years or so. Willy is ~14’ long and since we couldn’t find an inexpensive board stretcher we decided to scarf the boards to get the desired lengths.

Scarfing has been a huge pain in the neck, first we built a scarfing jig for a router—basically a ramp at a 12:1 ratio. Unhappy with the resulting feathered edges of the scarf we experimented with a table saw scarfing jig. This jig worked really well for the narrow chines but it is limited by the height of the blade to about 2 ½”. I tried to come up with a fool-proof way to run the board through a 2nd time to get the other half of the cut but eventually decided to wasn’t very repeatable or accurate. So I went back to the router jig and played around until I started getting nice square looking edges on the scarfs.

Router Scarfing Jig Tricks

1. As the wood gets thinner and thinner it has a tendency to start to lift up at the leading edge. Clamping it more aggressively will not stop this from happening. The result is a ragged leading edge if you just continue to finish the scarf. The trick is to elevate the back end of the board, this will keep downward pressure on the leading edge so that you can get a nice square finished edge.

2. Slowly advance the board along the scarfing jig taking medium depth passes at the beginning and lighter passes as you get close to finishing up.

3. Draw a line across the jig base to indicate the intersection between the base and the router bit. By doing this you will finish all of your scarfs in the same position and of course know when to stop (note: if you move the board beyond this point you will probably get a ragged edge cut again).

4. Another advantage of elevating the back end of the board is that you don’t need to clamp the board into position—instead I just used a small anvil as a weight to secure the board and had no troubles with the board moving during routering. Tip – check the location of the anvil by looking at the front edge of the plank, if it is too far back the leading edge of the plank will start to rise up off the base of the jig.

Using this method I found that scarfing can be a very rewarding and easy task with highly repeatable results. Although I will continue to use the table saw jig for smaller pieces of wood as it is much quicker and yields excellent results.

Gluing up the scarfed boards has been a long process that has been dictated by the speed at which our epoxy hardens. We purchased Industrial Formulators G-2 epoxy because it will cure in colder temperatures which has been a real blessing as there have been very few days so far this year when our “boat shed” (read garage here) has been above 70 F for much time. The downside to this epoxy is that it takes a long time to set up, generally 24 hrs. Consequently we have been gluing up 3-4 boards every day for the past few days and are just now ready to start the process of planking. But first we need to finish up the transom and get it installed—stay tuned!!!

The Journey of the Stem

Hi,

Sorry about the delay in postings. Although we endeavour to keep our followers informed, it sometimes seems like building can come to occupy blogging time. As we are tentatively planning to finish this craft by Summer, it seems as though we need every opportunity to work that we can. Anyways, significant progress has been made since the purchase of materials, and the stem is now completed.

Stem Pieces and Templates

As mentioned previously, we decided to build the stem out of three laminated mahogany layers. By doing this, we hoped to achieve the required 2.5" while still keeping weight (and costs) down. The adhesive of choice for this task was System 3's G2. Originally used to construct aircraft, and designed to have superior joint strength and flexibility, we figured that it would be ideal for the task. Anything that can be trusted to keep a plane in the air is definitely good enough for a little knockabout sailboat. In addition, this stuff has incredible open time--it will remain workable for up to 4 hours after preparation! This is extremely useful when one needs to glue several joints (eg all of the scarfs for the planking), as it does not place pressure on expedience, which ultimately leads to mistakes. Because Atkin specifies a 2-piece stem in the drawings, we had a total of 6 pieces to cut out and keep track of. After roughing components to size with a jigsaw and finishing with a router and template, we epoxied them to form the finished stem. A 2.5" thick stem is truly formidable when completed! As the mahogany we selected is fairly hard, we are confident that the stem will handle any abuse it might face. Another step in the journey of building a boat!

Glue-up of the Stem

The next challenge was that of the stem rabbet--a daunting task to first time builders, as a mistake here can tarnish a beautiful piece of wood. Problematically, the plans do not illustrate the rear delineation of the rabbet-the bearding line. Although we had a general idea of the position of the stem line (the front boundary of the rabbet), the bearding line was a bit of a mystery. However, after some puzzling over the plans and reading others' accounts of this step, we found that, in fact, the process used to determine this line is fairly straightforward. From the overhead view of the craft in the plans, which defines the angle at which the planking meets the stem, it is possible to use trig to complete the calculation. Knowing the width of the planking and the angle, one can find the hypoteneuse (the distance between the bearding and stem lines) at both the top and bottom of the craft. From here, a batten between the lines lends the shape the rabbet must take. For a more in depth account of this process, I highly reccommend the Unlikely Boatbuilder's blog. Finally, our preparations for the build have paid off! Using a mallet, a few sharp chisels and a fid (a small piece of wood the same dimensions as the planking), the stem rabbet can be cut. I know that it's frustrating that all the books leave it at this, but it is a process that is much easier to experience than to explain. Being sure to make careful, conservative cuts and checking progress with the fid often will ensure a tight fitting rabbet. It truly is not as difficult as it may seem.

Rivets and Roves for the Hull

316 Stainless--Pricey Stuff!

Lastly, while on vacation, we obtained our required hardware from Jamestown. With this and a completed stem, there is little that still stands between us and planking. Dauntless, we shall press forward into the realm of spiling battens, lap bevels, gains, and much more.

JoeLapstrake   

Spinning my Wheels

The frames are built, the strongback is assembled, the chines are 80% done, and now I need a bunch of things to move forward. 

First on the list is wood for the stem and transom.  The plans call for white oak for the stem and mahogany for the transom.  The stem is 2 1/4" wide, or 10/4 material....a look at the local hardwood vendors proves to be fruitless for anything that thick as a single piece, some guys have some 8/4 but that just won't do.  So the only choice is to glue up two or three pieces to get what I need, the problem is that oak is not a good candidate for gluing with expoxy because of the high tannins levels.  This leads to a long investigation into the merits of the various glues that are appropriate for below the water line useage.  Turns out that the choices are limited to epoxy and resorcinol. 

Resorcinol is the glue that is used to make marine grade plywood and what everyone complains about is the dark glue that it leaves and the fact that it is not a gap filling glue, in fact the surfaces need to be well-mated and clamped for the glue to do its stuff.  On the positive side it can be used with oak and no one has any horror stories to tell about failing joints--even after 20 years.

Okay I'm in, resorcinol it is then.  Here comes the spinning my wheels part...turns out that resorcinol is not easily available around here so now I'm back to square one.  But a little more knowledgable on glue!

Decided to try out a local hardwood wholesaler called PJ White that I had heard will sell retail also.  Turned out to be a good move, as I was pulling up to the yard I see a guy driving a fork lift with 8-10pcs of mahogany out to a contractor's truck.  Beautiful looking boards all between 10 & 14" wide, 4/4 material each board 16' long.   They carry two types of mahogany, african and honduras, african is about 1/2 the price of honduras.  Ended up buying a single 11" wide plank, 16' long with nice figure (thought it will look nice if left bright on the stern of Willy) that I cut in two with a handsaw in the yard before loading it into my Volvo wagon.

The 4/4 material turned out to be closer to 5/4 so my plan is to plane a little off one side, glue them together with epoxy and use one of the 8' mahogany boards for the stem.  I will have to find a use for the remainder of this board.  But, the price was so good from PJ's that I can't go wrong--about 30% cheaper than the other local suppliers.

Feeling pretty good about getting the wood and glue issues all resolved but then started thinking about that mahogany and wondering what the moisture content of that wood might be???  Don't have a moisture meter so I am a little resistant to start cutting it to size and thickness right away.  Besides, there are still more problems that I need to solve before I can go much further.

First on the list is to order fasteners.  The original plan was to use copper nails and burrs and silicone bronze screws.  Jamestown Distributors was the vendor of choice (seem to have the best prices) but when we went to place our order we discovered that the price of silicone bronze screws went up 80% (we were stunned!!!). 

This led to a massive internet search on the pros and cons of using either bronze or stainless steel.  Both seem to have there place in wooden boat building but the clincher for us was a post by a boat builder on Vancouver Island who was replacing the hull on his boat that spent the last 15 years in salt water and said that the stainless steel screws he was removing were all in excellent shape.  That is more than enough proof for us prairie boys that only have some fleeting hopes that our boat will get into the salt off Vancouver Island some year.

I also changed my mind and decided to use roves instead of burrs.  The nails for the roves are smaller in diameter than the nails I would have to use with the burrs and since our planking is 3/8" I was concerned that the larger holes would impact the structural integrity of the plank edges.

With all this time on my hands I decided to would be a good idea to mock up the stem and see if we really understand how to create the rabbet.  So we took a piece of spruce 2x10 and laid out the stem from our lofted pattern.  Really quite simple, we drew the stem up on a piece of 1/4" ply so we just put some nails through the key points along the perimeter and then using a batten re-drew the stem on the 2 by.  

Once we had the rabbet line and the bearding line (following the instructions from the "Boat Builders Apprentice") in place we made a fid (a fancy name for a piece of wood the same dimensions as your planking) we starting working away at chipping out the rabbet with our chisels.  

When we put the stem into place we were pleased and a little surprised to see that our rabbet was good ( a little rough but passable).  

All that chipping with a hammer led to another project--making a proper wooden mallet.  Found a great plan by Diego de Assis that provides all the proper dimensions --http://www.wkfinetools.com/contrib/dAssis/art/mallet/mallet-1.asp

I made mine from some scrap maple and consequently built the head up out of 3 layers rather than the single piece that Diego uses.  If you decide to build yours this way here are a couple of pointers that will save you some head scratching.  

1. Use an adjustable square to set the angle of the handle and the insides of the center mallet head pieces.  Once you set this angle you can easily lay out all these pieces and then cut them.

2. Glue up the head in sections, position and glue center head pieces (2) to one of the side pieces and let it cure.  Then glue the other outside piece in place. It is much easier to build it up in phases rather than dealing with a slimey, moving mess of all 4 pieces at once.

So far I have been really impressed with how well this tool works.  At first I thought the angle on the head might we too much but after using it for a while I can tell you it is perfect!

Joe 

How to put a clamp on things

Clamps are an essential part of any boatwright's arsenal. They find countless uses around the shop and are downright indispensable when laying laps. However, it always seems like one needs just a few more than he/she has. The boatwright is then faced with a question: "How shall I obtain more?". There are two options: buy some or build some. Unfortunately, the former is usually quite a costly affair, as clamps run anywhere from $7-$25 apiece. When you need to place one every foot on a 14' boat, it puts quite a dent in the project funding. Because of this, many people (including us) turn to the latter approach. Some design very elaborate bandsawn clamps, but, in our experience, it is much easier (and faster) to use a simpler approach. Using the method outlined below, it is possible to turn out clamps for under $2.50 each.

Firstly, it is important to determine what depth of reach is required. As we will be using 6" lap material, our clamps must have a deep throat. A 12" piece of 2x2 fits the bill perfectly. For pads, we used 1/4" material for the front part of the clamps, and 3/4" for the backs (ensure that the difference between widths is at least the same width as the joint to be clamped--otherwise the clamps will skew, reducing holding power). For hardware, we recommend 4-6" carriage bolts and 3-wing poly handles (available from Lee Valley). The plastic handles provide much more leverage than a wing nut, not to mention a lot more comfort. The photographs below should make it easy to copy our method

All of the parts for one clamp cut out (mise en place, as the French would call it). The 5/16" hardware ensures sturdiness.

After drilling a hole in each of the clamp halves, thread the bolt through...

Et voila, un clamp!

Hope that this tutorial helps to clear up any confusion surrounding the creation of clamps (and keeps a few hundred $ out of the hands of those Jorgenson guys :)

Joe Lap