Construction Log: Molds, Harpin and Sheer

February, 1980

Richard had bolted five floor timbers thru Abrazo's keel before we raised the backbone on February 3, 1980. (Blog: 3-31-15).  After the party, he completed the remaining floor timbers, bolting them into the deadwood of the backbone.

Then he was back on the loft floor with the lines drawings, where he began to take patterns for the molds that would form the armature on which the shape of the boat could be constructed. 

Four molds in place.

From each of the ten stations in the lines drawing, the MOLD defines the shape of the hull, taking into consideration the methods of construction.  In Abrazo's case, the upper part of the mold shows the curve of the hull at each station, LESS the thickness of sheer clamp, frame, and planking; while the lower portion of the mold, that part below the bottom bilge stringer, shows the curve of the hull less the thickness of planking alone.  (Richard planned to use the "inside-outside" method of bending the oak frames to which Abrazo's planking would eventually be fastened.  More on that when we get to framing.)  

As of the first week in March, 1980, we worked at "Horning" the molds; that is, using strings of equal length attached to the centerline of stem or stern post, we made sure that each mold stood exactly parallel to the next, and exactly perpendicular to the waterline.

For some boat-builders, the next step would be to wrap sheer clamps around the molds, and then put in a few deck planks to hold the shape of the sheer clamps.  Richard's guru, Bill Modrell, who'd built many sailboats during his years at Triple and Everett Marine Ways on the Duwamish River in Seattle, advised him to make the harpin first.

So, mid-March, Richard began work on the harpin, that piece of the boat's skeleton that will form a frame under the deck planks.  All of the deck beams will be fit to the yellow cedar harpin.  And every one of the steam-bent oak hull frames will be fastened into notches in the harpin.  Taking a pattern for the harpin was a complex task, though Richard says it was not hard to do on the loft floor.  The boatbuilder takes the curve from the plan view (i.e. the shape of the deck as seen from above) and expands that curve to match the sheer line, which is the curve of the deck as seen in the profile view (from the side).  If you used a batten to measure the length of the curve in the plan view, and compared that to a batten used to measure the length of the curve in the profile view, you would find a difference of a few inches. 

Maybe this is a little bit like what a tailor has to do to get the sleeve of a shirt to fit properly into the armhole of the shirt.  In sewing it's called "easing."  In boat lofting it's called "expanding." 

With the yellow cedar harpin resting in place on top of the molds, and permanently fastened to stern post and bow stem, Richard began work on the deck framing that would bind the two harpin pieces together across the width of the boat. 

But first, our friend Peter Fromm, professional photographer, stopped by for a visit to check on the progress of construction.  Peter made us stop work, and pose for a moment with our  Creation In Progress: 

By April 7, 1980, the construction drawings from Manuel Campos had arrived in Bellingham.  Richard proceeded to layout the deck framing now that he could see exactly where the mast was to meet the backbone, and where the cockpit opening and the forward hatch were to be.

While spending many hours on the loft floor taking patterns, he also had to put in a few hours on the highway (Interstate 5, that is) traveling to Seattle to purchase clamps.  Bar clamps, long and short; C-clamps, large and small; he bought every clamp the old boatbuilders, Bill Modrell and Warren Everett would sell.  He knew he would need many, many clamps during the next phases of his work:  framing the deck, placing the bilge stringers and ribands, and then framing the hull. 

Remember the Theory of Rolling Balls?  Even while you are hard at work pushing one project along, you had better also be preparing for the next project!

April 21, 1980: Richard is fastening every other deck beam to the harpin

Deck beams are notched to fit underneath the harpin.  Here you can see the C-clamps that hold the latest deck beams in place for fastening.  Richard bolted every other deck beam through the harpin.

C-clamps and bar-clamps are tools used over and over again as various parts of the boat are joined together.  The Sheer Clamp, which Richard built next, is part of the skeleton of the boat:  yellow cedar boards that define the curve of the deck, perpendicular to the harpin. The sheer clamp is nailed temporarily to the molds for positioning, and fastened permanently to stern post and bow stem.

Bilge stringers and ribands came next.  The bilge stringers are three permanent members, parallel to the sheer clamp, that define the width of the hull.  Ribands are planks temporarily attached across the molds to help define the hull shape while the ribs are bent into place.  

Early May, 1980.  First ribs, also known as frames.

We managed to get five frames steamed and bent and clamped into place the first day of framing.  That night, I made some notes in my journal: 

"Our first day of framing Abrazo.  I mentioned to my spouse things I’d noticed, like how hard it was to turn the clamp handles.  Richard has been clamping pieces of wood together for weeks now, and his hands were tired.  My hands are soft.  Still, we got five frames in today.  Only 75 more to go. 

"If I’m going to continue participating in this project I have certain options:  1) Find a different task, so I don’t have to wear my hands out on the clamp handles;  2) wear gloves;  3) Get tough.  Continue using my hands at the clamps and my hands will continue to become more useful for that job. 
Could this be a metaphor for life? 

"As Richard and I exchanged thoughts about this day’s work, we evolved some different techniques to try tomorrow. Tomorrow we aim for seven frames."

Okay.  More on the whole business of framing in the next episode.  But to conclude, please have a look at the following photo, taken in February of 2016.  Here you see, from inside Abrazo's cabin, the harpin and sheer clamp, with one deck beam crossing between them:

The deck beam is notched to fit against the harpin.  You see the bolt that goes from the bottom of the deck beam up through the harpin.  You see two of the oak ribs (aka frames), barely showing behind the sheer clamp.  The ribs fit into notches in the outer edge of the harpin, and you can see that there's a bolt through the harpin into one rib, as well as a bolt through the sheer clamp into that rib.  At the far right, you can see the notch of the next deck beam between the harpin and the sheer clamp.  Notice that there's a bolt at the bottom edge of the sheer clamp?  It goes into the deck beam.  Richard bolted every other deck beam through the harpin, and every OTHER deck beam through the sheer clamp. 

Last year, 2015, one of our potential buyers, a man named Jeremiah, who never did get to see the boat in person, asked for photos of Abrazo in profile.  After studying those, he commented that the boat has "held her sheer line" ... something that wood boats sometimes fail to do.  He said he thought the failures were often due to faulty lofting.  Richard replied that in his opinion, the integrity of Abrazo's sheer line is strong because the union of harpin, deck, ribs and sheer clamp is so solid. 

Onward.  At the present time, April of 2016, Abrazo rests at the dock there in Puerto Montt with all her sails stowed down below, and her covering tarp lashed against the winter weather.  We believe the man who will be her new captain is preparing to take ownership.  In the meantime, tune in soon for the next chapter of the Construction Log. 

Drawing is not to scale!