Sunday, August 24, 2014

Eastport Pram Build: Is That a Daggerboard I See Before Me?

So, this last couple of weeks have been all about major milestones.  These were the steps I've been dreading for months.  These are the steps that make or break the boat's fit and finish - the difference between a professionally built boat and one slapped together by a wood butcher.  Okay, so enough melodrama, let's get to it...

First, the daggerboard slot in the center thwart.  This had two very specific criteria, it had to be perfectly straight and it had to land perfectly on the slot in the daggerboard case, which wasn't perfectly rectangular due to the plywood warping.

This is another advantage to building templates - I was able to mock up a slot and see how it looked and fit.  I set the template in place and traced the underside profile of the centerboard case.  I know that the sides are 1/4" and I know how thick the ends are so I was able to find where the slot should land.  My first attempt on the template was done by plunging a circular saw into the masonite.  This cuts acceptably straight lines when doing rough carpentry, but not what is basically fine furniture for the boat thwart.  I was at least able to determine any offset issues on the finished seat.  Remember, the seat is laminated, so if I botched it, I'd have to cut out two more, glue them together, etc. so it would set me back a couple of days.

That's just about the time the I remembered I had a spiral upcut bit for my router.  This is the exact application for this bit - cutting a plunged slot.  I marked the exact location of the slot on the real seat, setup a straight edge for the offset of the router base to bit, checked the bit location on the slot at least three times and did a shallow "test cut".


"Test cut" on seat...

A few more passes and I cut all the way through, but the daggerboard didn't slide in.  No worries, I planned for that to tweak the width so that the slot falls right on the centerboard case.  I put the real seat in place on the boat and determined that 1/8" wider on the starboard side should do the trick.  I moved the straight edge 1/8" and made another pass.  Now for the test fit - it fit perfectly.  Whew!  It looks CNC machined!  A little 220 sandpaper and the slot is finished, and at least as importantly as the aesthetics, the daggerboard fits perfectly.  Remember, I don't want the slot so wide that the daggerboard has a lot of slop, but I also plan on adding several coats of epoxy and possibly graphite and/or fiberglass.  Now to make the daggerboard go through the hull.  Yikes!

Slot cut perfectly...

Daggerboard fits perfectly with little slop...

Epoxying the centerboard case to the hull is the next big step.  I buttered up the mating surfaces, including the 1/4" edges and set the case in place.  I'd already drilled the screw holes and counter-sunk them for the silicon bronze screw heads.  Once in place, the leading edge of the case wasn't touching the curvature of the hull, so I added some weight.  Perfect!

Centerboard case curing in place...

The next day, I mixed up another batch of peanut butter and did the fancy fillet.  Remember, the centerboard case is the most structurally important part of the hull.  Imagine running aground at a few knots and hitting a rock - all of that force is instantly shock load transferred to the case, so the fillet increases the bonded surface area, making the case pretty much bulletproof in case of a catastrophic grounding.  Hopefully, I'll never have to test it...

Centerboard case fillet...


The centerboard case fillet should also be aesthetically pleasing since it's smack dab in the middle of the boat and is displayed quite prominently  on the finished product, so I smeared some peanut butter, waited for it to semi-cure, and sculpted it into the fancy fillet shown below...

Forward fillet fancied up...

Aft end fillet...


Now for the moment we've all been waiting for...  Cutting the hole in the hull for the daggerboard.  This is by far the most important make or break moment in the boat build.  I could've made another seat if I'd botched the slot, but I can't make another boat at this point.

Ironically, this is the only time where I actually had to go buy tools to accomplish a build step.  I bought a 12" drill bit extension to drill down through the installed centerboard case.  One on each end and a couple down the middle to destabilize the hull so it doesn't fight the router bit.  The 1/2" flush-cutting trim bit is absolutely necessary to insert through the pilot hole and follow the inside edge of the daggerboard slot, cutting a perfectly matching slot.  The reason why the slot in the hole has to be perfect is because I don't want a lip for the daggerboard to hit as I'm dropping in the slot, possibly delaminating the hull from the case.  Also, the machining process can't mar the waterproofing on the interior of the slot, so the following router bearing is the perfect solution.  If I'd just blindly cut the slot with a jigsaw, It might not have followed the inside of the slot perfectly, either creating a lip or cutting into the walls of the slot and it probably would've damaged the waterproofing layer.  Keep in mind the finished hull/case assembly has to be totally waterproof since it's below the waterline and will be very difficult to repair if it sustains any water damage.  I did cut a slot between all of the pilot holes to further undermine the strength of the part of the hull being removed.

Flush cut trim bit.  Router rests on the bottom of the upside down hull.
Bearing follows inside contour of imperfect centerboard case shape.


Pilot holes and connecting jigsaw slots.  Ready to route...


After a deep breath, I dove right in because procrastination would only increase my anxiety.  Inserting the router bit into an enlarged pilot hole (Confession:  I rocked the drill bit side to side stupidly while enlarging the pilot hole to fit the router bit, thereby nicking the interior of the case.  Sigh...  I'll fix that later.), I very gingerly routed out the slot.  Remember, the wood is fiberglass reinforced on both sides.  I didn't know if it would cut smoothly or just gouge giant chunks out of my boat.  The good news is that the newly sharp bit cut through the hull like butter...  Perfectly matched slot with the interior of the case, so no lips and no further interior damage to the waterproofing.


Perfect slot...

Right on the centerline...

Now for the moment of truth, dropping in the daggerboard.  SUCCESS!  It slid perfectly right down through the seat, case and out the bottom of the hull!

Houston, we have a sailboat...

Like a proud papa, I can't get enough of this shot...


 So now it was time to affix the center thwart.  Peanut butter on the edges of the daggerboard case and beam support, then drop the seat in place with weights to hold it in place.  Little did I know that the port side got caught on the edge of one of the side panels so it didn't drop totally in place.  Of course, I discovered this the next day after the epoxy had cured.  It's one of those "only I can see it" things that's prevalent in my larger woodworking projects.

Weights holding center thwart in place...


Center thwart affixed and daggerboard installed...





Everything on the centerline as expected...


So now came the step that I hadn't been looking forward to, but not necessarily dreading - epoxying all of the undersides to make the flotation tanks watertight.  I set the boat on the floor since I couldn't reach bending over with the boat on the sawhorses.  I then spent a few hours on my hands and knees buttering up the undersides.  Note:  I didn't try the pastry bag trick because I would be squeezing the peanut butter upwards, but the trade-off was that I needed a bunch more peanut butter to apply the initial bead, then reclaimed most of it when I scraped it with the filleting tool.  The end result was a lot of wasted peanut butter at the end.  I'll need to figure something out for the aft thwart. I also didn't bother smoothing the underneath fillets.


Fillet under the forward thwart to make flotation tank watertight...



Finished fillet around edge of forward thwart...

Added rough fillet to center bulkead/thwart assembly...


 Okay, now to seriously think about adding the skeg and skids...  I cut my skids a lot thicker than the plans for two reasons, first more protection while dragging on the beach, second I the skids couldn't be any thinner than my tablesaw push stick for safety reasons.  This meant that they were going to be very difficult to bend to the bottom contour of the hull without stressing the attachment points while the epoxy was curing.  To put as much prebend as possible in the skids, I bent them over a "form" and continuously wetted them out with water.  After a day of wetting and drying overnight on the "form", they sprang back to almost straight - just about an inch of bend.  Sigh...  Oh well, at least I tried.  I was able to pretty easily flex the skid over the hull without putting severe stress on the bottom.  I guess I'll give it a go tomorrow...




New totals:
  • Installing daggerboard case = 1 hour
  • Daggerboard slots in seat and hull = 1 hour
  • Filleting undersides of thwarts = 3 hours
Total:  60 hours
  • Drill bit extension = $8
  • Flush cut trim router bit = $20
Total:  $983

 Captain Skully out...

Sunday, August 10, 2014

Eastport Pram Build: The Whole is Greater Than the Sum of its Parts...

So, a lot of stuff happened again this week, but the finish line seems to keep retreating just over the horizon.  I over-drilled (1/2" hole for a 5/16" bolt) the holes in the rudder as per the directions.  I also over-drilled the holes in the rudder head cheek plates, which I'm not sure I was supposed to do as per the directions.  The directions weren't very clear at this point.  I think it's a case of the writer knowing what he meant, just not explaining it quite clearly enough for someone else to follow (which is something I do all the time).  My reasoning is that they will both be through-bolted and exposed to water, which needs to be isolated from potential damage.  The good news is that it's easy to put a piece of tape on the bottom of the hole in the rudder and fill it with epoxy.  It's not quite so easy to fill the holes in the cheeks.  I put tape on one side and filled it through the hole on the other cheek.  Tomorrow, I'll drill out the proper sized hole (5/16") in the epoxy and put tape over the other hole and fill it from the other side.  Although these parts don't take a lot of wood, they do take several steps to build, so I'd like to keep this one for a while.

Also, I test fit the rudder into the head and cracked it open a bit, which I'll have to fix.  The directions say to grind away some of the top of the rudder (see lighter part below around hole), but I need to remove more wood further down the rudder where it pried the cheeks apart.





I'd been wondering about where to source some Sitka spruce or clear Douglas fir for the spars.  That was proving to be logistically difficult and expensive.  While wandering Home Depot the other day getting stuff for the shop, I discovered some very clear hemlock boards.  I had originally thought of poplar because it was cheap and clear, but they only call poplar a "hardwood" because the tree has leaves instead of needles.  Actually, pine is much harder than poplar.  Really, the only thing I make out of poplar are drawer cases and drawer dividers.  Anyway, a quick check on my phone in the aisle said that hemlock is not substantially softer than any of the other wood people have used to laminate their spars with on the boatbuilding blogs, so off I went with three sticks.

The mast is supposed to be 1-7/8" square, and my three sticks were just over 2" thick when stacked, perfect for laminating.  The boards were 2-1/2" wide, so plenty of room to trim off from both sides to clean up the glued edges.  When I got back to the shop, I noticed that my plethora of 2" clamps didn't quite span the three boards, which was a pretty serious problem.  I'd planned on clamping the mast lamination as securely as I had the outwales.  In the end, I just spread out the glue (have I mentioned my Rockler glue roller?), stacked the boards, clamped it to the bench with the few large clamps I had and put really heavy things on it.  BTW, I'm still repeating the same mistake of using Titebond II.  If this project is going to fail, I want it to be epic.  Can you say Viking funeral?


Hemlock glue-up...


The next day, I removed the weights and clamps and the glue up looked pretty good.  I set the table saw to just over 2" so I'd have room to shave the other side on a second pass and with the help of a friend and work, wrangled the 10' stick through the cut.  This is when you can really see if the lamination worked, and mine looked pretty good.  I rand the stick through a couple more times on the other faces to get a square cross section.  I'm always quick on the draw to do a test fit, especially if it's fun, so I ran over to the boat with the mast and tried to stick it in the hole in the forward thwart.  The square edges kept if from sliding in, but it looked close.  I would have to route the edges to make sure.  I took everything outside and did all my routing and sanding and it fit with just a little slop.  I figure I'll wrap the mast where it goes through the thwart with some chafe protection and it'll be nice and snug.  There are various holes to drill and I still have to cut it to length, but that's an important part of a sailboat almost ready to go!


Mast laminated...


Speaking of Home Depot, I've got to give a shout out to their "Bucket Head" vacuum that fits on one of their 5 gal buckets.  It's a great little wet/dry shop vac and costs about $35.

There have been other processes that needed to happen that I'd been dreading.  Remember if you biff something at this stage, you're out the wood and all those days of cutting and gluing.  Now it was time to cut out the handle on the daggerboard.  If done properly, it looks professionally made.  If not, it looks like some kid cut it out to sail on a pond on summer vacation.  Luckily, I've had lots of experience with templates, so I rough cut out the hole in the handle and set about fine-tuning the 1/4" masonite template.  It faired pretty quickly so it was time to slap it on the daggerboard and bust out the pattern following router bit.  Things went pretty well, except for the fact that it might be nice if CLC didn't make any curved edges tighter than the router bit.  This was true for the daggerboard and the transom handles.  It would've been much easier if I/they had stuck to any radius larger than 3/4".  Otherwise, I had to do a lot of fine-tuning with a hand file.  Note to self for next boat...

I think it turned out pretty well.  Note the tight radius...

Speaking of "next boat", the Port Townsend Wooden Boat Festival is only a month away!

 Now let me get something off my chest.  I've mentioned it before, but CLC says to wait until the boat is structurally built before adding the transom doublers.  They specifically mention this time and again in the directions, even correcting when the doublers are shown installed "too early" in the photos.  Since I made the mistake of following the directions on this step because they made such a big deal about it, here are the extra steps I had to go through:


  • Custom fit doublers around 1" radius fillets in the corners of the boat.
  • Glue the doublers onto the slanted transoms using heavy weight to push the doublers against the transoms since I don't have deep enough clamps.
  • Refair the edges of the transoms so the doublers match perfectly.
  • Route the hand holes into the transoms which are at a very weird angle while holding a 15 pound router very precariously.  If I had botched this step, it could've ruined the boat.
  • Redo the 1" fillets around doublers.

That's a lot of extra time, potentially dangerous and what I consider unnecessary steps.  I think I will ask Mr. Harris personally at the boat show exactly why I'm not supposed to glue the doublers in place before I stitched the boat together.  This is definitely a case of "but all the other guys are doing it"...




Aft starboard transom handle.  Looks pretty good...

So the other night, I mixed up the ubiquitous batch of "mustard" epoxy with silica and glued the rudder head together.  It squeezed out, making me feel like I had a good bond.  I was careful to clean up the squeeze out inside, between the cheek plates with an acid brush so it didn't interfere with the rudder.  While outside, I used my belt sander to grind down all of the epoxy and fair the rudder head assembly.  This was a part composed of two separate parts, which each had their own templates, which turned out slightly different for some reason.  Once glued up though, you can sand them to the exact same shape.



Rudder head glued up...

With the understanding that any epoxy step is by definition an overnighter, I've been trying to think of a critical path to limit the number of days/steps.  Here are some of my critical path criteria:

  • Before I epoxy the thwarts in place, the air tanks have to be waterproofed.
  • Before I install the aft thwart, I have to install the skeg.
  • Before I install the skeg, I want to get as much stuff done on the inside of the boat as possible because the skeg interferes with how the boat sits on the sawhorses.
  • I still have to do the scariest part of building the boat and cut the hole in the bottom for the daggerboard slot.  I have to figure out the best way of doing this and how it dictates epoxying in the middle thwart.
  • I have to epoxy the forward thwart in place and install the skeg in order to determine where the mast base should be installed for proper rake.  This directly counters the sawhorse dilemma.
So I set the thwarts in place and traced their edges in the hull to determine the exact shape of the air tanks.  Then, I mixed a small batch of unthickened epoxy and painted everything below the line.  This caused the fillets to be really glossy and darkened the oak nicely, which gives a great preview for what the finished interior will look like.


Air tank waterproofed...

As you can probably tell, even when I'm home, I think about the boat a lot and boat stuff.  Since I also love t-shirts, I thought I'd try to create a stencil for a shirt to commemorate the build.  It's still a work in progress because I need to find a proper shot of an Eastport pram with enough contrast to make it stencil worthy.  Here's a first attempt based on the product image on CLCBoats.com.  

Possible t-shirt designs for Port Townsend...
Might even make one for John Harris...


Which version do you like better?

Where we were last episode:

Previous totals:
50 hours
$559

Where we are now:

  • Laminating mast, waterproofing air tanks, laminating and sanding rudder assembly = 5 hours
  • Hemlock for mast = $45
  • Pintles & gudgeons = $96
  • Lug sail kit and tools = $255
New totals:
55 hours
$955

Wow!  It really adds up quickly...

What's next?  Well, I made a spreadsheet punchlist to make sure I try to stay on the critical path.  None of the seats are still attached, the centerboard is still sitting on the bench, so I've still got a lot of structural stuff to get done.  It's an interesting dilemma that the sailing kit parts take so much time, effort and money, but I could still just putter around in it if I get just the boat part finished.

Okay, by the time I got this post written, I've already made some progress on the boat for the next post.  To be continued...


Captain Skully out...