19.1.22

Fixture freedom

 Deck complete, the boat was structurally very stable and finally ready to be removed from the framing fixture.  I put the beginnings of this boat in the fixture back in December 2016!  After removing the screws, the first exciting task was to get an accurate weight.  Up to this point I had an estimate based on the weight of what I was putting into the boat.  It came out to 52.3 lbs.  This is about what I think is expected for a Mistral at this stage in the game.  Lots of hardware and work to do still so I am not too concerned about how to get to the 75 lb. class weight minimum.  Before getting started on the bottom, I took some progress pictures:




Back in the garage, it was time to fair and finish the bottom with glass cloth.  The first step was to add material and fair the bow.  I intentionally cut the bow off and added a skeleton piece of plywood to build up the volume of the bow at the waterline.  
After putty application

Port side after fairing

The next step was to glass the hull.  I put a layer of 8 oz. cloth on each side with a 4 inch overlap along the keel.
dry fit and trimming of glass cloth

view from the aft end of the boat

After wetting out the cloth

After glassing the boat bottom, I faired the hull along the glass cloth overlap edges and put a couple more coats of epoxy over that to build up and smooth out the bottom.  Taking advantage of a warm, sunny day, I put the boat outside to finish curing. I intentionally didn't put the UV stain on the front of the boat.  The assumption was that it was going to get a bunch of fairing compound added and would require paint.  Maybe not the best decision in hindsight, but it is what it is.  I will paint the front when I'm done adding epoxy and fairing the bottom.  The mahogany stain is a really deep red.  Looks like a glass of cabernet.  Thankfully I still had some of the alcohol based stain and was able to touch up in places where sanding was needed.  


The next area of focus is on the blades.  I picked up a piece of alder wood for this task.  This species is strong and light.  I laminated 1" strips of the wood with each adjacent piece rotated and flipped 180 degrees to ensure the boards don't bow later down the road.  The daggerboard is 5'-6 at the moment, but this will probably get trimmed down.  









Button up the deck

With a slight drop in temperature and a little time for garage projects, I got back to working on the boat in November 2021.  The interior structure of the boat was previously completed so it was time to put the deck on.  I made templates with poster board for all the pieces and then cut the wood equivalents in 3mm ply.  Thinking ahead, I also made a carbon fiber/plywood tiller that is curved at the forward end to get over the deck tapers at the aft end of the hull.  The last boat had serious tiller issues since it was a rushed afterthought.  Not making that mistake again.


The bow was completed first and glued down.  After that I worked on the tank closeouts at the back of the boat. 



With the bow and aft tank pieces cut, the tanks were fitted and prepped for gluing. Also seen below is the first shot at making hiking straps.  I made a second pair in black since these are wee bit too flashy for my taste.  When you use up what's lying around this is what you get.  The boat is slightly narrower at the beam than a mistral.  I am going with a two strap configuration for two reasons.  1:  I have short legs.  2:  to compensate for the reduced leverage from a smaller girth. I am looking to comfortably get my mass farther from the hulls center of buoyancy.


After lots of sanding and fairing at the deck joints, the top side was ready for glass.  At this point the boat was less than 50 lbs so I could afford to completely glass the topside.  

Prepping glass cloth for lamination

Some cold nights required tenting and heaters to get my slow cure epoxy to kick


Deck after glassing

Deck after 2 additional epoxy coats.  It's starting to look finished!




1.8.21

Adding some bones to the boat

I got this really cool rook pattern carbon fiber on closeout and wanted to use it somewhere.  I figured the floor of the cockpit would be a good place.  It's an area of the boat that needs to be tough and a location that I can show it off without taking too much away from beautiful wood grain of the plywood.  I put down the carbon fiber and a layer of  4 oz glass over the top.  

The green tape is locating the inside location of those gunwale tank bulkheads.  The next step was gluing in those bulkheads. 

After they were sufficiently staked in, a fillet of epoxy filler and glass tape was added on both sides to further strengthen the bulkhead junction to the hull.  

Next up, splines were added between bulkheads for supporting the tank skins.  

The trickiest pieces to define were the vertical walls of the tank.  I made templates from construction paper for each side along with the foredeck top.  My buddy Nori helped out as much as she could.


After shaving down each side to a tight fit, I glued and clamped them in.  


I decided that the tanks didn't need to extend all the way to the transom so I tapered them to a point just forward of where the traveler will attach.  The picture below shows the boat after those faceted pieces were attached to the back of the gunwale tanks.  

Next I added the splines between bulkheads to define the top of the tanks. It is starting to take shape!  










Production resumes

 Forgive me Blogger, for I have sinned.  It has been 5 years since my last post...

After finishing a masters degree, a bathroom remodel and then a kitchen remodel, I found that I had some extra time and some additional construction confidence.  With some renewed interest in finishing the boat project and making some extra garage space, I dusted off the clamps and wood planes and got back at it.  

When I left off in 2016, here's where she stood:


Before I detail recent progress, I need to rewind to 2018 when I had a couple days of motivation.  The deep V in the bottom of the cockpit on these boats not really comfortable when standing.  I decided I needed a floorboard to provide a nice flat place for feet.  I glued in a nice place to mount the forward end of the floor board and then glued down the board.  I also added some additional support behind the aft bulkhead to provide some meat to screw in the hiking strap eyes.  


A couple gallon paint cans provided the necessary weight to ensure a good faying surface bond with the bottom of the boat.  I also added a couple layers of carbon fiber where the partial bulkheads for the gunwale tanks will be.  Fast forward to 2021 for further progress...



29.1.16

Foundation

Back in the boat, I began adding the structure for the mast step.  First up was a solid composite stackup of carbon on the hull where the mast tube will be affixed.  I added a horizontal piece of plywood for the mast step on top of that.
Next I added another healthy stack of material over that to stiffen and distribute the load from the mast base.
Next up was the remaining bulkheads.  This would include the aft centerboard trunk bulkhead and the aft cockpit bulkhead.  I'm really happy with the shape of the boat with the temporary bulkheads in and I'm pretty sure the boat is off script from the initial design.  I pulled the shape from inside of the hull using a jig I made and 1.5" strips of plywood that slid down the slot in the top.  I then transferred the shape to some construction paper for the bulkhead pattern.  It worked great!
Transferred to the pattern material:
Reminds me of a calculus class.  Area under the curve, anybody?  Nerdy engineering moment there.  If you know what I'm talking about feel free to comment.  This process was repeated for the remaining bulkhead locations. I cut out and glued in these bulkheads.  The cockpit geometry is starting emerge now.  I like it. 
Next up I glued in .750 x .500 rails around the perimeter of the bulkheads where the deck will attach.  This added structure and gives me a surface to bond the deck too. 
All clamped up:
To increase the stiffness of the transom where the rudder will eventually attach, I added a composite laminate to that area.  I did the same at the bottom of the aft cockpit bulkhead where the hiking straps will bolt in too.


15.1.16

Back in black

Bring on the roll of carbon fiber.  It's time to build some composite parts.

First up was the mast tube.  I like the rocking mast tube concept that we did on the Rodger Wedges so I will do that again.  While other boats in the fleet selected to go with a slot shape for the top of the tube, I was concerned that building the mold for this shape would probably frustrate me.  Additionally, I would like to support the tube along the forward surface internally,  This is difficult when it's cylindrical and only makes contact at the tangent point.  I went with a square cross section with 1/2 inch fillets on the edges.  The mold was easy to build and the part popped out nicely.  I have a plan for ensuring that the tube doesn't point load the mast when rocked all the way forward and aft, but we'll go into that detail later. 

Here's the mold made with MDF.
I wrapped it with release film and layered on the cloth. Here's the stackup I used:

0/90 3 oz glass
0/90 carbon
30/60 carbon
-30/-60 carbon
0/90 carbon
0/90 3 oz. glass

It came out right at the anticipated .090 thickness. Yay math! Stay in school, kids.
After I wrapped it, I added another layer of release film and then clamped it up.  I probably should have bagged it, but it didn't seem necessary for this part at the time. 

With a little brute force and awkwardness the tube released from the mold.  The inside turned out nice.  There's one void, but I don't think it's going to impact performance.


Here it is after a little clean up.


A touch of sanding on the outside and this thing is good to go.

Next up was the daggerboard trunk.  Same process. 
Here's the mold:

All wrapped up and going into a clamp I built for it to cure in.


Here's the finished product before trimming.  We finally had some cold weather and I didn't have any heaters.  Stuff I added to the boat finally cured up a day later, but the daggerboard trunk was moving slow so I popped it in the oven the next morning.  It kicked after that, but I think it embrittled the film a bit or it wasn't quite done when I pulled it off, either way, the film didn't come out of the inside real nice.  That's ok.  Less marring on the board with a polyester film touching it rather than the hard epoxy, right?


12.1.16

The boat's first trip and the advent of real progress

While ill advised in it's exceptionally unsupported boat-like shape, the moth made the thirty mile trip to it's new womb.  I wish I had some video or pictures.  I should have rented a moving van to do this, but feeling cheap (expensive attorneys will do that to you) I selected to move the 11' boat and fixture in my truck bed that is only 5'-6.  I took only back roads, I did it at night, and I couldn't go more than 30 mph to ensure the hull doesn't flutter it's way to some sort of failure mode.  It took me a little over an hour to make the trip. 

After finishing up the house remodel enough to live in the house, I was ready to start working on the boat again.  It's getting cold in most of the country, but not here.  It's still a lovely 87 degrees as my neighbors start putting their Christmas decorations up in this post Thanksgiving weekend. 

At this point the boat needs some real structure.  I built a couple forms for the holding fixture and secured the hull to these.  I also leveled the fixture in location.  It won't move again until the inside of the boat is complete.  The first step on the inside of the boat would be to put the rails on the gunwales.  Bring on the bucket-o-clamps - you will be busy for the next month.

  Rails cured, I put two temporary bulkheads in and screwed them to the holding fixture.  Next step was to start cutting and gluing in some real bulkheads.  If you're comparing this image to what you think a Mistral looks like, spoiler alert, they aren't the same, and yes, the bow is swept aft.   I spent some time working on a bow that removed a portion of that massive amount of volume.  Since the Mistral design is near impossible to pitchpole, I think I have some wiggle room in this aspect of the design. 
The other massive deviation from the Mistral design is the transom.  I am moving away from the parabolic or elliptical shape that had been previously employed.  It kinda looks like the old Rogers Wedge transom.  I built a fixture to help ensure symmetry and help ensure that there's a fair transition into the rest of the hull.  It worked well.
More bulkheads please...

Here's the dry fit.
And then glued and glassed in place..
The transom was next...
Finally, I intentionally hacked off the bow where the stem and keel meet.  I really was looking for a shape right at the bow entry that was a bit fuller and didn't have the concavity.  The Mistral design has the bow just barely kissing the water while sailing.  Hell, on the Mousetrap, you had to work to make the boat sail with the stem in the water.  I don't think I'm going to have a problem piercing the water with this design so I think this area of the boat required additional attention.  So after cutting off a diagonal section of the hull, I went back and filled it in with some pre-shaped plywood pieces.  Here's the first one going into place.