Inside IYRS 

Nov 8

Written by: Tom
11/8/2009 10:10 PM 

When you've got a lot of Beetle cats to be restored all at once, it's a good idea to employ economies of scale.


One could argue that it's best for everyone to cut and radius their own frames for their boats in order to get the maxim restoration experience, but let's be honest here.  Once you've cut a length of 3/4 x 3/4 oak and slightly radiuses the edges (the minimize splitting later), you don't learn a whole more by making more of them.  On the other hand, if you're part of a crew that's plowing through a stack of frames for the whole fleet of boats, you get experience working as a team for the greater good. 



You learn how to make and use jigs to speed up the work as well.  Here's a setup that allows the students to chamfer 2 corners of the frames in one pass.



You learn to be efficient, and to use carts to move giant piles of frames around.



You learn that working through these huge piles of oak frames does not take forever, although it can seem like it at times.  They eventually get done.



You learn that it helps to keep a sense of humor during this relentlessly slow task.



And lastly, when it's frame bending time, you get that warm fuzzy feeling that everyone is able to frame because of your work.  That rocks.

While the frame crew is working, other students are engaged in smaller projects.  Some are learning how to use a metal lathe to cut the initial threads on their centerboard bolts.  Here, Walt Ansel walks a few students through the process.









After the threads are mostly cut, the students do the final threading with a hand tap.  


One could argue that if you were doing this on an actual restoration, you would just jump right to the hand tap rather than taking the time to set up the lathe.  That's true, but at school, it's a better idea to learn how to use as many tools as possible, and the metal lathe is a great one to be familiar with.  

There was a deadline for getting the ribbands on the Beetle cats, and it looks like everyone made it.  





Ribbands are sturdy lengths of straight-grained wood, usually pine or fir, that are fastened to the molds over the planks.



They make a solid, cage-like backing on the outside of the planks.  Not only that, they make a fair curve as they sweep along the length of the hull.  



When the hot frames get bent into the boat, they exert a lot of pressure against the planks.  Without the ribbands to add support, the frames would distort the planks outward, and leave you with a lumpy boat.

The ribbands also act like battens, showing high and low points in the fairness of your hull.  Here, a student has found that one of the older molds he's using to establish the shape of his boat has a section that's a little undersized.  The ribbands ride about an 1/8" above this part of the mold.



If he were to pull the ribband down against the mold, he'd end up with a slight dip in the hull near this section.  His solution is to make a thin shim that just rides between the mold and the plank.



This will allow the frames to reference to the fair line created by the ribband.

Some folks are finishing smoothing out the epoxy that holds the lead weight in the centerboard.



Over on the Gar Wood, framing is moving right along.  The transom frame is painted and set in place.





Although the old transom frame is no longer needed, we'll keep it around until the boat leaves the shop.  



You never know when you may need to reference the original.

With the frames in position, you can start to imagine the sweep of the hull more easily.





You can see the chine log on the floor to the right.  It will eventually be fastened into the notches along the frame on the right corner.
(above 5 photos by Jens Lange)

The keel is getting some final shaping and should be ready for installation soon.



On the Chris Craft, the students have been forming and steaming their new chine logs.  Here, the port log is just being clamped into place.



This is definitely an All Hands On Deck maneuver.  The hot oak has to twist and bend along its length, and they need to get it locked in place before it cools and stops being so compliant.

  

You can see that they've got their frames and stringers (the unpainted longitudinal members) all installed.  They're making excellent progress.

There's a lot of fine tuning going on over at the 12 1/2.  Mostly this involves fairing fairing fairing.



The process involves using the stiffest batten that will follow the shape of the boat and stretch it along frames to the edge of the transom.



The goal is for the batten to just touch the frames and transom.  When you get it just right, it's time to smile.  

Tags:

2 comment(s) so far...

Re: Whole pile O' frames

Nice curves.
Can you explain how steam helps to make the wood more pliable and how long you have to work the wood before it cools. Does the wood remain bent after it cools?

By Peter on   11/11/2009 7:45 PM

Re: Whole pile O' frames

Hi Peter,
Here's a nice, short article on steam bending www.danenbergboatworks.com/steam_bending.htm but I'll summarize here. You can think of wood as a bundle of straws held together by glue. The glue is called lignin. When wood gets hot, both the straws and the lignin soften a bit. This allows the straws to bend, and the soft lignin allows the straws to slide past each other. All the steam really does is transfer heat (via moisture) throughout the wood. Bending works better with green wood, or wood that's been soaked, because there is more moisture in the wood to transport the heat. The rule of thumb is to steam for 1 hr / inch thickness of wood. Thus, a board that's 3/4" thick should take about 45 minutes. It's important to remember that it's the heat, not the moisture, that does the work. In fact, if you steam wood for a very long time, you'll end up drying out the wood because the heat is helping to drive the moisture out of the wood.

How long you've got to work with the wood varies by species, initial moisture of the wood, ambient air temperature, and of course, the thickness of the wood. Thick, moist, dense wood will hold the heat longer, and thus stay pliable longer. The general rule is to work as fast as you possibly can. Have your bending jig and clamps all set up ahead of time so you're not slowed down by looking for clamps. Keep your steamer close to your work. We pull a frame out of the box and try to have it bent into the boat within a minute, 30 seconds if possible. You'll know when the wood has cooled, it'll be hard to bend and will tend to shatter rather than bend.

Bent wood will hold its shape after cooling, usually with a certain amount of springback. To compensate for this, folks will set up their molds with some overbend in them. That means that the mold radius is a bit smaller than the final desired radius. If you want to bend something so that it will end up in a particular curve, you'll need to do a little experimenting to find out how much your wood springs back and then alter your bending to account for that. In a boat we don't worry about that with the frames because the springback pushes the frames out against the planks and helps to keep everything in close contact.

By Tom on   11/12/2009 7:17 AM

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.