Sunday, July 27, 2014

Eastport Pram Build: Progress as Promised - It's All Coming Together...

So, a bunch of stuff happened this week.  Mostly good...  With the understanding that I'm trying to show the process in a bit more detail, here's a closeup of how the middle bulkhead was tabbed in.  This is with a smaller radius than the finished fillet.  This allowed me to pull the wires out without dealing with the cured epoxy.


Closeup of tabs...


Here's the filleting tool that I made for the finished fillets.  It's a 2" plastic scraper that will create a 1" radius fillet as per the instructions.  I marked out the center and radius and cut/filed/sanded it to it's final shape.


Before...

After...

Here's what the finished fillet looks like after smoothing with denatured alcohol.  The seat supports are easy to fillet on the outside because the intersection angle is greater than 90°.  The inside is much more difficult.




Here's what the finished fillet looks like from on top.  1" radius on both sides creates a super strong joint because of all the surface area involved on the mating parts.  People kind of look at the wood flour fillets like they're ugly, but all I see is a strong joint.  Remember, a little sanding will make them prettier and when the adjacent wood is epoxied and varnished, it will be considerably darker, making the contrast between the fillet and the wood less noticeable.


Looking straight down on center bulkhead...

Finished fillets smoothed with denatured alcohol...


There are several places in the directions that I think they leave you hanging.  One of the easier to fix ones is that you're evidently supposed to install the center seat after you've created the fillets to hold the center support in place.  This means the slots cut into the ends of the seat won't fit over the fillet, so I cut an arc in the seats to match the fillet.  This will also be covered with a fillet when I secure the seat in place. 

Modified seat to fit around fillets...


After I got the center seat to fit, I immediately put the daggerboard case template in place to support the seat.  It fit perfectly!  It even matched the contour of the bottom of the boat.


Seat in place, supported by daggerboard case template...


It was now time to install the outwales.  I had been dreading this step.  I had to make a run to Harbor Freight to buy a dozen c-clamps.  The directions say one every eight inches, so on an 8 foot boat, that's 12 clamps.  At $2 each, that's a smart investment in making the boat turn out right.  BTW, I could've used more.  Anyway, I was now ready for the most challenging part of the build, the 8' laminated outwales.  I had an 8' piece of quartersawn white oak that when cut into strips fit perfectly.  I had a difficult time determining in the directions how large to make each strip (2 per side to make the bend easier).  Between the drawings and the directions, I found that each strip was 3/4" x 1/2", which would result in an outwale that's 3/4" x 1" (plus the 1/4" plywood, making the gunwales of the boat a respectable 1-1/4" thick piece of wood.  A perfectly structural and stiff edge to the boat.


Quintessential boat builders pic...

Because I only bought enough clamps to do one side of the boat at a time, I had to do four separate layups.  Because I'm using slow hardener, that meant four nights to cure.  That was another thing I was dreading because I'm sort of in a hurry to splash this thing.  Anyway, I was able to find all kinds of other stuff to do while the outwales were curing.  There were a bunch of other parts to fabricate that I had put off.  I had originally only cut out the structural parts of the boat, but now I had an opportunity to cut out the daggerboard, case and rudder assembly parts.


Lamination complete...

BTW, make sure you start at the bow.  The curve is compound, both outwards around the curve of the boat and downwards to add some beautiful spring to the shear line.  You will definitely need a gloved helping hand with this part.  Otherwise, You'd probably smear the "butter" all over the side of the boat.  I mixed up a batch of  that was stuff enough to spread like butter down the length of the oak strip (remember, I'm making an oak version, not the standard mahogany version).  Then I spring clamped it in place, close to it's final position.  While I was adjusting the oak and the clamp (make sure you have the clamps pre-set for the thickness of what you're clamping including pads - read scraps - to protect the wood), I had my buddy raise or lower the other end of the strip.  This allowed me to fine-tune the strip to exactly match the curve of the hull.  If there was ever a discrepancy, I made sure the plywood edge was higher because it would be easier to sand down than if the oak strip was too high.  This method worked really well, four times, and later that week, I had the outwales laminated.

The next step was to buy a flush cut saw from Rockler.  It was a flimsy piece of crap that barely lasted long enough to get the job done.  A flush cut saw's teeth have no offset, so they don't mar the surface they're sliding against.  I normally use these to trim off wood dowels that I use to plug screw holes in furniture.  I'm hoping that I'll be able to sand the edges without burning through the oak veneer on the transoms.  I was also amazed how the epoxy flowed in to the joints during the original lapstrake assembly process.  It's now all exposed.  It also shows why, when people leave their transoms bright, they mask off the edges of the plywood which gets painted at the same time as the hull.


Trimmed flush with transom...

Okay, the next major step is putting together the daggerboard case.  This is an important part of the process.  Not only does it support the seat, but if you're making the sailing version like me, you have to use the interior of the case as your template for cutting the slots in both the seat and the fiberglassed bottom of the boat!  This is step in the boat build that I'm fearing the most.  But first, you have to waterproof the interior of the daggerboard case.  Once assembled, you can't get into the slot to epoxy it.  I applied three coats of unthickened epoxy to the "bad" sides of the two daggerboard case sides.  Of course, my boss had to touch the epoxy before it cured, but luckily it flowed back and covered the fingerprint.  The epoxy on the case sides was also a preview of what I'll be facing when I epoxy the whole boat.  The sides had offgassing bubbles and dust nibs all over it.  If I'd been worried about how it looked, I would have had to do a considerable amount of sanding, which removes a substantial amount of the epoxy you just applied...  So after the three coats had cured, I mixed up a silica thickened cup and buttered both sides of the spacers.  The spacers were made up of three layers of 1/4" plywood glued together to create the perfect slot width for the daggerboard (which is made up of two layers of plywood.  The extra layer leaves room for all of the layers of epoxy that will be applied to the surfaces involved.  The daggerboard slides nicely in and out, which is what you want when you sail up to the beach and have to pull the daggerboard up quickly.  Keep in mind that if you run aground with the daggerboard down, the impact shock torques the hell out of the daggerboard and case, which can seriously damage the boat.  The daggerboard case is the most structurally important part of the boat and therefore the most difficult to fix if something goes wrong.  That's why I've spent the extra time to hopefully make the case assembly bullet-proof.

Daggerboard case glue up...




Daggerboard case in place.  Fits perfectly...

 The directions call for screwing the daggerboard case in place to the center bulkhead and through the boat bottom with silicon bronze screws.  These are preferred by boat builders because stainless steel screws would eventually corrode because the screws will be encapsulated in epoxy, thus starving them of oxygen, removing their stainless properties.  Ironically, my company is supposed to sell silicon bronze screws, but due to internal purchasing issues, we don't have them in stock yet.  As such, I have to go buy SB screw somewhere else.  Sigh...  At least they're not expensive.

While all of that was going on, I cut out the hole in the front seat for the mast and installed the doubler.  I epoxied the doubler in place then trimmed it flush with the router.  Make sure your ease the edges of things that are getting laminated first, because it'll be much more difficult to do later after it's glued without damaging the veneer.  This is especially important for before you install the transom doublers.


Slot for mast.  Note the doubler underneath...


Now it's time for another confession.  I used Titebond II, which is "weatherproof" vs. Titebond III, which is waterproof.  Possibly a very serious mistake, but it's what I had a gallon of already before starting this project.  My hope is that the epoxy barrier coat protects the wood and glue, and if not, won't the plywood swell and peel apart before the glue I used becomes an issue?  Marc Spagnola (aka The Wood Whisperer does a good job of describing this).

While we're talking about the front seat and the slot for the mast, my front seat support fit almost 2" farther forward than on the plans.  This was so substantial that I posted on the CLC boatbuilders' forum about it.  Nobody got back to me about it so I forged ahead.  Now, I think I'll have to modify the mast step base to properly secure the mast in position.  The good news is that the mast is still located in the same spot, so it shouldn't affect the design of the boat under sail.

Finally, I think I've decided to put a graphite bottom on my dinghy.  This will increase it's scratch resistance while launching and also provide UV resistance while it's upside down on my truck.  West Systems 423 is pretty much the only game in town.  I got mine from our sister company Go2Marine.com, but it's not listed on their website.

Anyway, I'm off to sand down the outwales, the edges of all the parts I laminated this week (i.e. daggerboard, rudder assembly, etc.).  I'm ready to fit the transom doublers in place (another place where I think the instructions erred).  Now I have to custom fit the transom doublers around the large radius fillets I created when I first put the boat together.  A lot of the blogs and even the directions show the doublers already laminated to the transoms when the boat goes together, with a note that says the doublers were installed too early.  A little frustrating because now I'll have to put another set of 1" radius fillets over the doublers after I get them glued into place.

I think that's about all for now.  I've been a bit busy actually trying to make progress to remember to stop and take pics of everything. Plus, I'm constantly distracted because I'm building this at work.  It's been really cool though, when a family comes in to look at the boat and the dad and the son both start drooling and asking questions.  That's pretty much the best part of this project, the product knowledge to gain and share.

Captain Skully out...

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