Monday, July 20, 2015

Hully Cow!

Stitching is an awesome time in S&G boat building since your 2D planar pieces rapidly become a 3D boat. At one moment all you have are several flat panels. A few hours later you have a boat.

I usually call this moment "Stitch Day". However, working alone with panels that are 3 feet x 24 feet, this stitch job will take more than a day. Maybe I'll call this "Stitch Week"

Lowering side panels from ceiling where they
have been stored for a while



Lowering...




Separating and placing the side panels on the continuous deck



Getting close...





Really close...




Installing spreaders...





Got a few stitches in to stitch the side panels to the deck...

Working alone, I am having a bear of a time getting the panels lined up and held in-place then letting go to install a few stitches. 

One stitch at a time...


The top of the 9mm side panels is flimsy so I installed some temporary stiffeners. The future backer, knees and shear deck will provide permanent stiffening. I installed the temporary spreaders then used a level and plumb bob to get the panels and deck symmetrical. The temporary knee braces will hold it that way until gluing is done.

Temprorary stiffeners, spreaders and knee braces
Back to stitching. All stitches are coated with paste wax before installing. Epoxy doesn't stick to wax so the stitches are easily pulled after the epoxy cures.

Stitching the stem




Once the stitching is done, the gluing part of "stitch and glue" can begin. Gluing is applying fillets made of thickened epoxy then overlaying the fillets with fiberglass tape set in epoxy. 

There was a time when I would try to lay a perfect fillet, let it cure, sand it perfect then lay the fiberglass tape on top of the sanded fillet. Never again...

I prefer to install the tape before the fillet cures. This provides a primary bond between the fillet and the tape. But, more importantly, it means I do not have to shape my fillet perfectly. I can be lazy when shaping the fillet. I apply the epoxy-saturated tape while the fillet is still soft. I use my fingers (wearing latex gloves, of course) to shape the fillet after the glass tape is laid on top of the fillet. I work all of the air bubbles out of the tape at the same time.










Once the fillet and tape cure, the stitches are pulled.


Wubwails

I decided to install three rubrails on each side panel. The rubrails will serve to stiffen the 9mm panels and add some pretty trim. Two rub rails will be 11 and 21 inches down from the shear line. The last rub rail will be at the shear line. The rub rails will be installed using temporary clamping screws, installed from the inside of the side panel, so no screw holes show in the final rub rail.

Dry fit of lower rubrail. Masking prevents the oozed-out
epoxy from contacting the side panel.


I cut saw kerfs in the rubrails in the area where the rails must curve with the side panel. This makes bending the rails easier, prevents straightening of the side panel and reduces residual bending stresses in the completed rubrails. The kerfs are filled with thickened epoxy after the rail is installed.

Saw kerfs in lower rub rail. There is a mirror image of the
rub rail in the shiny side panel.




Saw kerfs in lower rub rail




Completed installation of starboard lower rub rail. Yikes that
side panel is dusty. Good thing I vacuumed the gluing area before
installing the rubrail.



Completed lower and mid port rubrails

With the lower and mid rubrails installed, the 9mm side panels are not so flimsy and I can remove the temporary top stiffener. This allows access to the top of the side panels and the knees and shear deck can be installed. I put in some temporary spreaders midway between the lower and mid rubrails.

New temporary spreaders. Screw holes thru side
panels are at the rubrails so no holes are
visible on the outside.


After spending 2 weeks getting the sheer deck installed, the side panels are now stiff enough that temporary spreaders are not necessary. I sure got tired of stepping over those things. 









It is time for another flip. First, mount some temporary supports and wheels.







Flip her.



Viola! That was too easy. 



A fly in the ointment! In my UV the Captain blog I concluded that I will omit UV protection from the BW. However, I have been approach by a friend who is very interested in buying the completed BW. I am willing to omit UV protection from my own boat but I am not willing to omit UV protection from somebody else's boat. So, with the possibility that the boat will be sold upon completion I have changed my mind and will apply UV protection.


After completing the boat bottom, the sides were lightly sanded to remove the sheen and provide a profile for the varnish to adhere to.

Sides lightly sanded

Two coats of Pettit Flagship varnish were applied tot he sides.




Completed bottom and sides





Completed bottom and sides


And don't forget the sculpture!




THE FINAL FLIP !!!

Wheel carriage in place







Tires in place




Up...





...and over





Time to plane and sand the tops of the inwhales and rubrails flush with the sheer deck then class the edge of the inwhales and rubrails.

Planing the top of the rails



Rails sanded flush with the sheer deck



Glassing the edges of the rails




The dross will be sanded
away later.



Dross removed from the sheer deck, weave filled, ready for varnish