Construction Log: Framing with Steam-bent Ribs, May 1980

Each of Abrazo’s frames, also known as ribs, was individually made of white oak cut from an Oregon forest in 1978, purchased by Richard in the spring of 1979 and stored in his shop until late April of 1980. 

Still on the “green” side, the oak held plenty of moisture in its cells; all the better for bending to shape.  Each rib was measured and cut by Richard, numbered, and tapered to fit into its own slot in the keel.  Each rib was oiled with linseed, then steamed inside a wooden box to make it limber.  The rib was then driven into its socket, bent and clamped to its proper shape, and fastened into place with custom-made stainless steel screws and bolts.     

Our first day of framing was probably Monday, May 5, 1980.  Richard prepared the oak frames at his bench in the shop.  His steambox, made of old growth cedar, rested on sawhorses in the yard.  He fired up the electric steam generator, oiled the first rib and slid it into the steambox to cook for its allotted time, about fifteen minutes.  Meanwhile, we clamped together a channel using scrap wood and wedges to guide the frame into its keel socket. 

You’ll recall from the blog entry titled “Molds, Harpin, and Sheer” that the shape of Abrazo’s hull was defined with the molds drawn from the loft floor.  When Richard cut these molds, he subtracted the thickness of the planking in the portion from the keel to the turn of the bilge.  Above that turn, he subtracted the additional thickness of the bilge stringer /ribband and the frame. 

Three bilge stringers, made of yellow cedar and permanently fastened at stem and stern post, run the length of the hull, port and starboard.  The stringers run parallel to the sheer clamp spanning all ten molds, one above and two below the turn of the bilge.  Many temporary ribbands span various molds to complete the shape that the oak frames will take. 

While steambox cooks the next rib, note that three yellow cedar bilge stringers are fastened at the bow.  All the other ribbands are temporary.

Using the “Inside-Outside” method of framing, the rib is driven Inside the lower ribbands and into the keel socket,

Ribands clamped to mold below the notch, with bilge stringer above. 

... then the rib is bent Outside the upper ribands to fit against the sheer clamp and into the harpin socket at deck level. 

While that first rib is steaming, we knock together the channel that will help force the frame down into the keel socket.  The socket itself gets painted with white lead, and we make sure there are plenty of clamps hanging at the ready.    

Before the first rib comes out of the steam box, the next rib goes in for its allotted time.  Then the first rib is pulled out of the box, and delivered to Richard, the Driver.  He jams the rib down between ribband and bilge stringer into the channel that has been created. 

Jay, the Inside Man, checks alignment.  The Driver wallops the rib with his topping maul, sending it deep into the prepared socket.  The Inside Man uses a flat bar to guide the rib, and drops wedges into the channel to push the frame outboard against the ribbands.  The Inside Man steers the rib as necessary with crowbar, flat bar, and hammer. 

The Ground Crew, that’s me, calls out “One inch more,” or “EEEasy!” and when the rib is in place I drill thru the tapered end into the keel socket and screw in the first fastening. 

Meanwhile, the Inside Man is clamping the rib outside the ribbands, bending from the bottom up.  The Driver is pressing the top of the rib toward its socket in the yellow cedar harpin.  Sometimes he needs to clamp a bar onto the top of the rib to give him purchase to twist  that rib into the socket, where it is clamped in place. 

Once the clamps have climbed up the rib, holding it to the ribbands all the way to the notch in the harpin, we check for fairness, bring the rib to its marks, and then break down the “channel” and move it to the next socket.  By this time, the next rib is steamed enough to pull for the Driver. 

After the day’s quota of frames has been bent, clamped and cooled, Richard will drill and fasten the ribs at the harpin, and through the sheer clamp and bilge stringers. There is a beautiful, almost biological tension forming as the ribs unite the harpin/deck structure with the backbone/keel structure. 

I re-pixeled the background above the boat to get rid of billboards and buildings for a better view.

Let’s admit there were plenty of other tensions generated during the framing process.  It’s a good thing the camera could not capture the language that sometimes fouled the air.  “Draft the clamp aft!”  “Don’t horse it, HOLD it.”  “Forget it!  I’ll take the clamp outside.”  “HOLD IT!”

 

If the rib breaks, the driver’s temper breaks.  Clamps are torn out.  The hand saw flails.  The pressure is on because there’s another rib due out of the steam box in eight minutes.  Tear down that scrap wood channel and get it moved!

Once, the oak rib - slippery with linseed oil - sprang from Richard’s grip and whacked his head.  Jay, his hands full of rib and clamp, almost let go to reach for his staggering boss, but Richard recovered his balance on the scaffolding in time.   

By May 8, 1980, we had a third of the frames in.  On May 15, our buddy Wade took the position of Inside Man for a while. 

On May 18, 1980, we were busy steaming ribs and driving frames when Mt St Helens blew her top.  Even though the volcano was 270 miles away, we heard her explosion as if it was the chlorine plant down the street, and the sound served to drive our energies even harder! 

 “It’s a #X!*#ing tapered frame!  Don’t tell ME what to do!”  A bad frame gets stuck in the socket.  Richard pries and hammers it out, with vehemence.  We go too long.  By the time we are all beat, and should quit, we still have two more frames in the steam box. 

The drill wouldn’t reach the socket.  I stretched too much on the wire, pulled the plug, and cut off the steam pump, too.  The burner runs on fuel however and continues heating.  I run around the bow, catching my back on a clamp.  Aieee!  And black smoke billows from the steamer.  We had our own volcano. 

Eventually those molds will be removed.

On June 9, 1980, Richard wrote another letter to Manuel Campos, with inquiries about adding 5 or 10 square meters to the sail area, and about some confusion regarding the shrouds.  He included photos of the construction process so far. 

“As you can see we are not sawing the frames but bending them.  They are of white oak and are closer together than indicated in your drawings.  I hope to be planking by the time this letter reaches you and will send more photos soon.”