Inside IYRS 

Ready to flip!

Jan 28

Written by: Tom
1/28/2010 9:12 PM 

The 12 1/2's hull is faired, painted and ready to flip.

 

The 12 1/2 is looking like a real boat these days.  The waterline is somewhat swoopy when you look at it from above,



but it's clearly flat when you get down to the level of the water.  



Getting a line to look flat across a curvy surface is just one of those things you learn when you work with boats.  



The boat is now ready to be turned right-side up.  It looks like it's almost finished, but really, it's just a shell at this point.

So, all the molds are unscrewed from the floor, and boat it lifted up.



Even with all the molds still inside, the boat is easily picked up by 6 people and moved.  There's a lot of mess to clean up beneath the boat before setting it back onto the building floor.



Now, if you're an astute viewer, you'll wonder why the building floor was so clean in that first picture of the students holding the boat. while it was a mess in that last photo.  Yes, that upper photo was totally staged, and they picked up the boat again just for your edification.  So, next time you see one of these sturdy fellows, tell them "thanks!"

Next, they'll set up bracing to hold the boat upright while they install the sheer clamps, decking, seats, bulkheads… it's a big list.

The Chris Craft team is moving along quickly, and their boat is clearly taking shape.  



Here, a student works out the screw locations for one of the spiled topside planks.  



The finished plank is held in place with clamps, and the screw holes are laid out and drilled to hold the plank in position once the plank is installed.  It's a little slow at this point, because you can only put one plank / side on at a time.  Each plank is fit precisely to the one above it.



And here's today's fastening fun fact:  screws should be installed with the mating parts already held together tightly.  The screws are there to hold the parts together, not to Draw the parts together.  In other words, one shouldn't use screws to pull two parts together; the parts should already be together.  That's why we use all those clamps when we fasten planks to frames.    

The Gar Wood's bottom planking is now on, and they're starting to work on fairing.



You generally want to use the longest plane or sanding block possible when fairing long, gently sweeping spans.





The longer plane will tend to average out little dips and bumps along the hull surface.  A short plane would ride up and down the bumps that a longer plane would span.  Instead of producing a surface with fewer bumps, the short plane would remove an equal amount of material from both the high and low areas.  This is why you see people using longboards (long, flexible boards with sandpaper attached) to fair boat hulls.

The chine log is the part that acts like a corner where the bottom and sides of the boat intersect.  It's the darker strip of wood just below the finished bottom planking in this photo.



If you look closely, you'll see the lighter wood on the underside of the chine log to the right.  That's the rabbet that was cut into the chine log, and the topsides planking will butt right into that little step.

The hull looks very nice in the afternoon light.



Most of the first years are still upstairs working on their construction drawings.  



The construction drawings show more than the shape of the boat, they show the actual parts and their locations in the boat.  In this lofting, you can see the shape of the stem of the dinghy that was previously measured, but there's much more than that.



For instance, you can see the locations of the bolts that hold the various parts of the stem and keel together.  You can see the shapes of the joints where all these parts connect as well.  Construction drawings are like an x-ray photo of the boat.

This lofting shows the location of each plank in a lapstrake boat, as well as the frame that they are fastened to.



These types of drawings look a lot more like the boat that you see in real life.



They include accurate locations of frames and thwarts (seats).  They often include cross sections of the boat taken at various locations along the boat.



It's quite a task to take this:



and turn it into this:



This is a slow, careful process.  The measurements that were taken from the actual boat are scaled down to make these drawings.  



Every part is accurately scaled so that a builder could use the drawing to determine things like seat thickness or the size of a bolt.  



Even details like the way that a thwart is attached to the boat are included in the drawings.



The students can't measure every single point along the curve of a boat, so they need to have a way to connect the points that they do measure in a way that accurately represents the sweeping curves of the boat. A set of drawing tools, called "ships curves," are used to help make fair curves in these drawings.    



Flexible battens held down with lead weights called "ducks" are also essential tools for creating fair lines.



We use battens quite a bit in boat building.  There's nothing else as useful for connecting a series of points together in a fair line.  You'll see builders using battens to lay out plank lines, water lines, sheer lines… House builders need their squares, boat builders need their battens.

Location: Blogs Educational Blog
Tags:

Your name:
Your email:
(Optional) Email used only to show Gravatar.
Your website:
Title:
Comment:
Security Code
Enter the code shown above in the box below
Add Comment   Cancel 
You must be logged in and have permission to create or edit a blog.